CIRP ANNALS 2025
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STC A |
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An LLM-enabled human demonstration-assisted hybrid robot skill synthesis approach for Human-Robot collaborative assembly
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Yue Yin, Ke Wan, Chengxi Li, Pai Zheng (2)
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STC A, 74/1/2025, P.1
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Keywords: Human robot collaboration, Manufacturing system, Human-guided robot learning |
Abstract : Effective human-robot collaborative assembly (HRCA) demands robots with advanced skill learning and communication capabilities. To address this challenge, this paper proposes a large language model (LLM)-enabled, human demonstration-assisted hybrid robot skill synthesis approach, facilitated via a mixed reality (MR) interface. Our key innovation lies in fine-tuning LLMs to directly translate human language instructions into reward functions, which guide a deep reinforcement learning module to autonomously generate robot executable actions. Furthermore, human demonstrations are intuitively tracked via MR, enabling a more adaptive and efficient hybrid skill learning. Finally, the effectiveness of the proposed approach has been demonstrated through multiple HRCA tasks.
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Generative AI for automated task modelling and task allocation in Human Robot Collaborative applications
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Nikos Dimitropoulos, Michalis Kaipis, Stavros Giartzas, George Michalos (2)
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STC A, 74/1/2025, P.7
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Keywords: Production planning, Human robot collaboration, Large multi-modal models |
Abstract : Task modelling and assignments generation is a complex and time-consuming activity despite the availability of modern CAx and planning tools. This paper proposes an AI based framework using Large Multi-Modal Models and a Digital Twin to automatically create task models, sequences and assignment plans through the processing of video streams involving visual and audio cues on the recorded resources, tools, and tasks. The same LMMs perform the task-to-resource allocation considering metrics such as human factors and resource workload. A case study on the assembly of white goods showcases reduction in manual planning, enhanced resources utilization and improved human-robot collaborative applications.
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Vision intelligence-conditioned reinforcement learning for precision assembly
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Sichao Liu, Lihui Wang (1)
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STC A, 74/1/2025, P.13
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Keywords: Robot, assembly, reinforcement learning |
Abstract : Robots that embrace human-level performance on precise, dexterous and dynamic assembly tasks can significantly enhance the efficiency in precision assembly but remains a big challenge. This paper introduces a vision intelligence-conditioned method for precision assembly, enabled by human-in-the-loop reinforcement learning. Upon visual demonstrations collected and trained by a reward classifier, a data-efficient reinforcement learning algorithm trains and learns vision-based robotic manipulation policies under human-in-the-loop corrections. An impedance-based control strategy derived from policies and visual guidance achieves high-precision contact-rich assembly manipulations with near-perfect success rates and compliance behaviours. The effectiveness of the presented method is experimentally demonstrated with semiconductor assembly.
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Beyond proxies: a direct time-optimal approach to robot cell layout optimization
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Jan Baumgärtner, Alexander Puchta, Jürgen Fleischer (1)
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STC A, 74/1/2025, P.19
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Keywords: Design optimization, Handling, Cycle Time Optimization |
Abstract : Cycle time is critical in robotic cells where material handling often presents a bottleneck and in turn depends on the cell layout. Optimizing robot cell layouts is therefore essential for improving cycle time. We show that the proxy objectives used for this optimization are poor approximations of the real cycle time and introduce a optimizer that directly measures the duration of the time-optimal robot trajectory. We show that it can offer competitive performance even faster than proxy-based optimization. We validate this performance on multiple problems and show how to integrate it into the cell design process of a manufacturing cell.
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Design and control of flexible handling systems based on mobile cooperative multi-robot-systems
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Tobias Recker, Annika Raatz (2)
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STC A, 74/1/2025, P.25
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Keywords: Robot, Flexible manufacturing system (FMS), Cooperative handling |
Abstract : This study introduces a scalable control framework for Cooperative Multi-Robot Systems (cMRS), enhancing flexibility in manufacturing by adapting single-robot motion sequences to multi-robot setups. The framework addresses kinematic overdetermination via a Virtual Robot Model (VRM), which centralizes motion specification without straining computational resources, allowing seamless scaling. Experimental results demonstrate that cMRS configurations with varying robot numbers can achieve object transport and handling with accuracy comparable to single-robot systems under admittance control. Although larger configurations show increased maximum tracking errors, average accuracy remains stable, demonstrating the framework’s effectiveness for scalable cooperative robotics.
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Increasing object flexibility of vacuum gripper systems through a common grasp search
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Rüdiger Daub, Paul Geng / Gunther Reinhart (1)
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STC A, 74/1/2025, P.31
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Keywords: Handling, Flexibility, Optimization |
Abstract : Gripper systems play a crucial role in robot-based automation. Frequent refitting hinders automation in companies with high product variance, but flexible gripper systems are costly. Therefore, this paper presents a software-based methodology to increase the object flexibility of standardized gripper systems during their design phase. The first step is to use clustering algorithms based on the physical properties of the workpieces to find similarities. Afterward, an optimization is used to identify common grasp points across workpieces. The approach is validated using vacuum gripper systems as a low-cost automation tool and printed circuit board assemblies (PCBAs) as exemplary workpieces.
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Conceptualisation of a multimodal, non-intrusive, generative AI-based assistive system for assembly
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Alessandro Simeone, Yuchen Fan, Dario Antonelli, Paolo C. Priarone (2), Luca Settineri (1)
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STC A, 74/1/2025, P.37
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Keywords: Generative artificial intelligence, Assembly, Multimodal assistance |
Abstract : The transition to Industry 5.0 highlights the necessity for human-centric and adaptive manufacturing systems. This study conceptualises a multimodal, generative AI-based assistive system for assembly designed to deliver real-time error detection and adaptive guidance tailored to diverse operator profiles. The system improves human-machine interaction by issuing preventive warnings to the operator prior to critical tasks, detecting assembly errors, providing multimodal corrective instructions during operations, and deploying robotic interventions when operator-driven corrections prove inadequate. Preliminary laboratory-scale implementation results show the system capability in mitigating assembly errors through dynamic assistive technology selection and iterative feedback learning.
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Constellation-based robotic visual servoing method for fault diagnosis of used printed circuit board assemblies
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Bence Tipary, Gabor Erdos (2), Zsolt Kemény
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STC A, 74/1/2025, P.43
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Keywords: Remanufacturing, Digital twin, Robot |
Abstract : The mainstream of diagnostic approaches of printed circuit board assemblies is optimised for large-scale industrial production, and is less suited for repair and maintenance during later stages of the product life-cycle. Main challenges include sparse documentation, small batch sizes and high product diversity, to which existing solutions are too costly, bulky or parameter-sensitive for industrial use. The paper presents a novel approach using computer vision, visual servoing and digital twins for robotic positioning of a measuring probe head. Subject to patent application, the method has proven its feasibility and affordability in live industrial practice with 99.80% success rate.
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Random wavelet kernels for interpretable fault diagnosis in industrial systems
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Haoxuan Deng, Samir Khan, John Ahmet Erkoyuncu (2)
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STC A, 74/1/2025, P.49
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Keywords: Keywords: Failure, machine learning, maintenance |
Abstract : Deep learning is a powerful method for fault diagnosis, but its "black-box" nature raises concerns in critical applications. This paper presents an interpretable, lightweight method combining random convolution kernel transformation (ROCKET) with wavelet kernels, which offer systematic time-frequency analysis and intuitive insights. Principal component analysis (PCA) is used to extract relevant patterns, forming a health indicator that guides maintenance decisions. A case study on linear actuator fault diagnosis demonstrates the method's balance of interpretability and computational efficiency, making it a valuable tool for reliable asset health monitoring in resource-limited settings.
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Vision-based robotic disassembly of aircraft engines with YOLO-SAM: a novel method for task orientation estimation
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Angelo Moroncelli, Sylvain Populus, Armand Rossi, Emanuele Carpanzano (1), Loris Roveda
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STC A, 74/1/2025, P.55
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Keywords: Disassembly, Robot, Vision foundation model |
Abstract : The growing demand for sustainable end-of-life management in aerospace has increased the need for robotic disassembly. This paper presents a novel pipeline for aircraft engine disassembly, operating in automatic and semi-automatic modes with state-of-the-art vision-based techniques. The key contributions are: (1) a method combining the Segment Anything Model (SAM) with YOLO for detecting removable bolts, independent of engine model and adaptable to various worn bolt types using vision-only perception, and (2) a SAM-based approach for estimating task orientation, ensuring precise tool alignment. Validated in simulations and real-world tests, the pipeline demonstrates high accuracy and adaptability for solutions in aerospace manufacturing.
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Sustainability of polycarbonate recycling via additive manufacturing
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Nan Yu, Yifan Yuan, Zicheng Zhu, Ruslan Melentiev, Long Ye, James Tinkler, Lukas Raddatz, Stephen T. Newman (1)
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STC A, 74/1/2025, P.61
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Keywords: Recycling, Additive manufacturing, Fused deposition modelling |
Abstract : Polycarbonate (PC) is emerging as one of the fastest-growing engineering plastics, but its potential for its application in a circular economy requires further investigation. This research explores the technical feasibility, carbon footprint, and economic impact of recycling injection moulding PC waste via fused deposition modelling (FDM) at a biotechnology manufacturer plant in the UK. The results show that recycling moulded PC scrap using FDM yields 3D printed parts with 88-98% of virgin PC mechanical properties, produces nearly 70% less carbon footprint, and saves up to 88% of costs than utilizing virgin PC material.
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Impacts of circular economy strategies on product carbon footprint: a lithium-ion battery case
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Haiwei Zhou, Wen Li, Sami Kara (1), Michael Zwicky Hauschild (1)
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STC A, 74/1/2025, P.67
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Keywords: Lifecycle, CO2 Emission, Circular Economy |
Abstract : Circular economy (CE) strategies hold substantial potential for reducing product carbon footprints (CF), yet their effectiveness and specific impact pathways remain unclear. This study develops a quantitative framework for calculating and comparing the CF under various CE strategies, demonstrated with a case of lithium-ion batteries (LIBs). Results show CE strategies have varying impacts on material and other flows in a battery lifecycle and do not necessarily reduce CF. A combination of six CE strategies halves the CF of LIBs, suggesting additional efforts are required for deeper decarbonisation. This framework offers insights to guide effective CE actions and advance sustainable products.
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A cradle-to-grave life-cycle-assessment of dry-processed Li-ion batteries for electric vehicles
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Yu Gu, Runming Tao, Chris Yuan (2), Hongchao Zhang (1), Michael Hauschild (1)
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STC A, 74/1/2025, P.73
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Keywords: Lifecycle, Electrode, Li-ion battery |
Abstract : Maxwell-type dry processing has emerged as a promising manufacturing technology for high-areal-loading Li-ion battery electrodes, offering a significant advantage by eliminating the use of the toxic and costly NMP solvent. This study developed a cradle-to-grave life-cycle-assessment model to evaluate the environmental impacts of this innovative technology, benchmarking the results against the conventional NMP-based technique for a configured 42 kWh NMC622-graphite battery pack. The findings reveal that the dry-processing method merits a 4.8% lower energy consumption and achieves environmental impacts up to 47.5% lower in 12 out of 13 categories, highlighting its environmental benefits compared with the NMP-based manufacturing processes.
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STC C |
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Towards understanding the surface strengthening mechanism in negative rake angle cutting of additively manufactured stainless steel
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Tingyue Bai, Chao Wang, Guangyuan Yu, Maxim Kolmanovskyi, Jannis Saelzer, Toru Kizaki (2), Dirk Biermann (1), Zhenglong Fang
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STC C, 74/1/2025, P.77
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Keywords: Surface enhancement, Negative rake angle cutting, Additive manufacturing |
Abstract : The design of lightweight transmission units highlights the importance of additive manufacturing (AM) techniques in gear production, however, it suffers from a limited understanding of the cutting induced surface enhancement mechanism subjected to inevitable negative rake angle cutting (NRAc). This work applies the NRAc method to process hardened AM-produced 17-4PH stainless steel made with 0°, 67°, and 90° hatching strategies, elucidating subsurface alteration mechanisms in distinct crystallographic textures. In-depth microstructural analysis and machinability evaluation revealed that the compressive stress-induced material removal process promotes a refinement-dominated deformation mode, leading to surface strengthening via grain refinement and martensitic phase transition.
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Directional-adaptive approach in machining of additively manufactured Inconel 718
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Amin Bagherzadeh, Ozkan Gokcekaya, Erhan Budak (1)
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STC C, 74/1/2025, P.81
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Keywords: Hybrid manufacturing, Modelling, Materials |
Abstract : The anisotropic properties of additively manufactured materials cause variations in surface finish, cutting forces, and machinability due to directional differences in material properties. This creates challenges in tool path selection for five-axis machining to achieve optimal process conditions. Additionally, traditional models and methods for process modelling and simulation often fail, leading to significant errors, as they do not account for material anisotropy. This work investigates the material behaviour during machining of additively manufactured materials, proposes a directional-adaptive flow stress model for accurate process modelling and simulation, and introduces an adaptive tool path selection strategy tailored for milling of additively manufactured materials.
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Ultrasonic vibration-assisted machining of Invar 36 alloy manufactured by wire arc additive manufacturing
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Ramazan Hakkı Namlu, Korcan Küçüköztaş, Hakan Kalkan, Bilgin Kaftanoğlu (1)
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STC C, 74/1/2025, P.87
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Keywords: Additive manufacturing, Ultrasonic, Hybrid machining |
Abstract : Invar 36, known for its low coefficient of thermal expansion, is widely used in applications like composite moulds, electronics, and optics. Although Wire Arc Additive Manufacturing (WAAM) offers high deposition rates and cost-effectiveness for Invar 36, it creates rough surface textures requiring machining as post-processing. In order to overcome Invar 36's machinability challenges, Ultrasonic Vibration-Assisted Machining (UVAM) was applied for the first time on WAAM-fabricated Invar 36. The results showed that UVAM outperformed conventional machining in terms of cutting force, surface roughness and topography, subsurface microhardness and tool wear with improvements observed in both building and deposition directions.
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Sub-surface sinking effect of reinforcement particle in laser assisted machining of metal matrix composites
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Omkar Mypati, Zhirong Liao (2), Shusong Zan, Rachid M'Saoubi (1), Dragos Axinte (1)
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STC C, 74/1/2025, P.93
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Keywords: Metal matrix composite, Laser, particle sinking, Machining, Surface integrity |
Abstract : Aluminium-based SiC particle-reinforced metal matrix composites are widely used in engineering applications due to their excellent mechanical properties. However, their machining remains challenging due to the mismatch of material properties between the brittle SiC particles and the ductile aluminium matrix, causing tool wear and surface damage. To mitigate these issues, laser inverse problem scanning is utilised to strategically melt the top layer aluminium matrix, allowing the SiC particles to sink and promoting more ductile Al-matrix. The strategic hybrid laser milling approach optimises particle sinking, reduces tool wear and enhances surface integrity by minimising particle fracture, pullout and refining microstructure.
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Sensorless in-process runout monitoring in milling via an industrial Edge device
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Mohammadreza Chehrehzad, Ismail Lazoglu (1)
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STC C, 74/1/2025, P.99
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Keywords: Milling, Monitoring, Industrial Edge Device |
Abstract : Runout in CNC machine tools is a critical factor affecting machining accuracy, surface finish, and tool wear. This article introduces an innovative sensorless approach for monitoring in-process runout during milling. In-process runout is assessed using an industrial edge device that analyzes spindle current and torque signals, which exhibit a strong correlation with dynamometer data. Frequency-domain analysis of the spindle current and torque signals enables sensorless monitoring of runout in real-time. Experimental results on milling of TiAl6V4 demonstrate the potential of this non-intrusive approach for in-process runout detection, offering a cost-effective solution to enhance machining efficiency and precision in smart manufacturing.
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An experimental methodology to improve the robotic drilling of aluminium alloys
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François Ducobu (2), Thomas Beuscart, Valentin Dambly, Edouard Rivière-Lorphèvre, Gorka Ortiz-de-Zarate, Pedro-José Arrazola (1)
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STC C, 74/1/2025, P.103
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Keywords: Drilling, Robot, Aluminium |
Abstract : In aeronautics, mastering the drilling process is crucial to meet strict quality standards. While robots provide a cost-effective solution for drilling large, complex parts, challenges arise in metallic materials due to their low stiffness. This study establishes a systematic experimental method to improve hole quality during robotic drilling of aluminium alloys. Holes were drilled in plates in four positions and 64 postures using a 6 mm tool to analyse their influence on a new defect index. A static deflection compensation method was developed to improve hole quality, addressing static deflection issues narrowing the gap between robotic drilling and CNC machining.
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Physics-based modelling and validation of dynamically varying thermal and mechanical residual stress fields in finish machining of aerospace alloys
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Julius Schoop, I.S. Jawahir (1)
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STC C, 74/1/2025, P.109
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Keywords: Sustainable machining; Surface integrity, Predictive model, Processing, Modelling, Uncertainty |
Abstract : While the physics of chip formation have been widely studied, there remains a need for greater qualitative and quantitative understanding of the way in which thermal and mechanical loads, and particularly their dynamic variability across length and time scales affect both the magnitude and variability of machining-induced residual stress (MIRS). This paper leverages an advanced in-situ characterization technique along with a physics-based process model to accurately and quickly predict key MIRS variables for aerospace alloys Inconel 718 and Ti-6Al4V. Our analysis clearly shows opportunities for digitally enabled predictability of engineered surface integrity to evaluate the fatigue performance of aerospace alloys more effectively.
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A physics-based flow stress model for cutting simulation of additively manufactured Alloy 718
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Amir Malakizadi, Rachid M'Saoubi (1)
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STC C, 74/1/2025, P.113
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Keywords: Modelling, Cutting, Additive manufacturing |
Abstract : A dislocation-based flow stress model is proposed to describe the behaviour of Alloy 718 fabricated using laser-based and electron-beam powder bed fusion methods. This physics-based model is adaptive to microstructural variations including the size and volume fraction of precipitates, crystallographic texture, grain size and the density of immobile dislocations. Coupled with data from thermodynamic and kinetic simulations, as well as insights from advanced characterisation methods, this model provides a framework for assessing machinability of additively manufactured Alloy 718. The predicted cutting forces and chip shape parameters showed a good agreement with the corresponding measurements.
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A novel approach to milling cutter temperature analysis with cutting fluid consideration
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Thomas Bergs (2), Hui Liu
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STC C, 74/1/2025, P.119
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Keywords: Milling, Temperature, Multiscale modelling |
Abstract : This study investigates heat transfer to the tool and the cooling efficiency of flood cooling under various cutting conditions using experiments and simulations. An experimental apparatus was developed to measure tool temperature during side milling with cutting fluid. Furthermore, a computationally efficient multiscale simulation method, combining engagement simulation and orthogonal cutting simulation, is introduced to predict process forces and heat transfer to the tool. The findings indicate that accurate orthogonal cutting models enable the multiscale simulation to predict cutting forces and heat transfer. The higher computation speed compared to chip-forming simulations makes the proposed method well-suited for industrial applications.
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Tool failure – a method for stress calculation of worn cutting tools
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Benjamin Bergmann (2), Jan Schenzel, Malte Kraeft
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STC C, 74/1/2025, P.123
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Keywords: Cutting tool, Stress, Wear |
Abstract : Basic knowledge of mechanical stresses is essential for an adapted tool design. A method for calculating internal stresses based on measured external stresses is shown. This eliminates the need for modelling the tool, chip and workpiece interaction as it is required in FE-based chip formation simulations. Thus, in-situ elastoplastic effects, such as springback or built-up edges, are directly considered. Using this approach, internal stresses of worn cutting tools are calculated at different wear states in order to understand tool wear. The experimental investigations show that for the machining of AISI1045+N principal stresses σ1 are the significant cause for tool failure.
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A novel multi-harmonic and phase-independent estimation of cutting force coefficients
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Zekai Murat Kilic, Joshua Priest, Sabino Ayvar-Soberanis, Srichand Hinduja (1)
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STC C, 74/1/2025, P.127
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Keywords: Machining, milling; calibration, cutting force coefficients |
Abstract : A novel frequency domain approach is proposed to estimate the cutting force coefficients through a dedicated analytical formulation. The method uses the amplitudes of the Fourier series harmonics and does not require any phase information. When compared to the average cutting force approach, the proposed method gives better accuracy even when few data points are used along the tool path. The method is verified by machining Ti6Al4V alloy with a variable pitch-helix tool using straight and slope cutting, the predicted coefficients are also validated by comparing them with those obtained using commercial machining simulation software.
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Model for temperature evolution in CO2 jets by Background Oriented Schlieren method for applications in cryogenic-assisted machining
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Koffi Samuel Koulekpa, Michael Deligant, Hélène Elias-Birembaux, Frédéric Rossi, Gérard Poulachon (1)
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STC C, 74/1/2025, P.133
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Keywords: Cryogenic machining, Cooling, Temperature, Predictive model, Optical |
Abstract : To optimize cryogenic coolant usage, CO2 and supercritical CO2 jets were studied using the Background Oriented Schlieren (BOS) method. Liquid, gas, and supercritical states were analysed under upstream pressures of 60 – 120 bar, temperatures of 30 – 40 °C, and nozzle diameters of 0.1 and 0.3 mm. The study quantified jet core temperatures (as low as - 80°C) and axial/radial temperature distributions. Experimental data informed a fit-based radial and centerline temperature evolution prediction, enabling improved thermal exchange modelling in machining applications.
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Improving the cutting characteristics of pure tungsten using a halogenated cutting fluid
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Kaveh Rahimzadeh Berenji, Shreyes N. Melkote (1)
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STC C, 74/1/2025, P.139
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Keywords: Chip, Surface modification, Embrittlement |
Abstract : This paper investigates the possible modification of the cutting behavior of pure tungsten, a difficult-to-cut refractory metal, by a halogenated cutting fluid. The results reveal that halogen adsorption on the workpiece surface during cutting induces embrittlement, leading to discontinuous thinner chips with cracks on the surface, and reduced cutting forces. X-ray photoelectron spectroscopy confirms halogen adsorption on the chip surface. An explanation based on the known effect of halogen adsorption on the electron work function of tungsten and its corresponding mechanical properties is given. The work shows the potential of the approach to improve the cutting behavior of difficult-to-cut metals.
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Improving cutting performance of nickel-based alloy by graphene modified diamond tools
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Ni Chen, Huiwen Chen, Bo Yan, Zhiyuan Mao, Ahsan Imran, Guolong Zhao, Ning He / K.K.B. Hon (1)
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STC C, 74/1/2025, P.145
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Keywords: Diamond tool, Nickel alloy, In-situ graphene |
Abstract : Inconel 718 is widely used in aerospace due to thermomechanical properties, but machining causes rapid tool wear. This study develops a covalent diamond-nanographite-graphene (CDGG) tool using nanosecond lasers and flywheel cleavage to convert sp³ diamond into sp² graphene, welds it onto a carbide handle, and sharpens cutting edges. The friction-wear tests and cutting experiments show that CDGG tool’s apparent friction coefficient is 49%–59% lower than diamond tool, rake face wear depth is 55%–65% lower than diamond tool, 75%–85% lower than ceramic tool. Graphene forms self-lubricating layers, minimizes wear, and enhances Inconel 718 machining efficiency and tool durability.
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STC Dn |
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Augmented geometry assurance digital twin with physics-based incremental learning
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Roham Sadeghi Tabar, Rikard Söderberg (1), Dariusz Ceglarek (1), Pasquale Franciosa, Lars Lindkvist
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STC Dn, 74/1/2025, P.151
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Keywords: Tolerancing, Digital Twin, Quality Assurance |
Abstract : This paper presents a novel digital twin framework employing batch incremental learning for geometry assurance. Addressing quality issues caused by part and process variation, the method evaluates three critical tasks: part matching, locator adjustments, and joining sequence. The proposed framework utilizes deep learning architectures, each trained on recursive simulation data. Employing incremental learning, the models adapt to new batch characteristics while maintaining predictive accuracy. A spot welded assembly demonstrated the proposed approach efficiency, achieving prediction accuracies with errors as low as 0.02 mm for part matching and 0.1 mm for locator adjustments.
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Enhancing tolerance stack-up analysis with variable-dependent admissible limits
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Mattia Maltauro, Roberto Meneghello, Gianmaria Concheri / N. Anwer (1)
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STC Dn, 74/1/2025, P.157
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Keywords: Product development, Tolerancing, Non-Geometrical Stack-Up |
Abstract : This work introduces the concept of variable-dependent admissible limits for tolerance stack-up analysis, where limits adapt based on geometrical and non-geometrical variables. Unlike traditional methods that assume fixed limits, the proposed approach integrates these dependencies into both variational and Monte Carlo analyses, enabling broader tolerances while maintaining functionality. A case study from the automotive sector demonstrates the methodology's effectiveness. This innovation shifts tolerance analysis from a purely geometrical to a functional domain, improving accuracy, reducing costs, and supporting compact and safe designs in industrial applications.
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Design optimization of graded cellular structures for additive manufacturing via differentiable Voronoi diagram
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Nanya Li, Changkun Sun, Hanlin Zheng, S.K. Ong (1)
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STC Dn, 74/1/2025, P.161
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Keywords: Design optimization, Additive manufacturing, differentiable Voronoi diagram. |
Abstract : Graded cellular structures offer a controlled distribution of material, resulting in customization of stiffness. This paper presents a novel design optimization method for graded topological structures based on differentiable Voronoi diagrams. Unlike conventional discrete Voronoi diagrams, which lack differentiability to solve gradient-based structure optimization problems, the proposed method leverages a SoftMax activation function to tune pixel regions into continuous stress field defined in a Euclidean space. Furthermore, pseudo site points and metric tensor have been applied for rotating and distorting Voronoi cells, so as to achieve much higher specific strength and energy absorption property than traditional optimization methods.
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2D profile-based surface repair and 3D pattern generative design via material jetting
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Pushkar Kamble, Hao Chen, Hanlin Liao, Yicha Zhang (2)
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STC Dn, 74/1/2025, P.167
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Keywords: Additive Manufacturing (AM), Material Jetting (MJT), Generative Design (GD) |
Abstract : Jetting printing processes rely on 2D pixel data derived from decomposed 3D models, which are often unavailable in applications such as surface repair and 3D pattern printing. Reconstructing 3D models and decomposing them into 2D pixels is time-consuming, energy-intensive, and prone to accuracy loss. This paper introduces a novel 2D profile-based design and control method, using 2D contour curves to generate precise pixels for jetting 3D volumes. This approach enhances efficiency, accuracy, and agility while reducing costs. Case studies on surface repair and 3D pattern printing validate its feasibility, with potential applications in multi-axis robotic systems and functional surface formation.
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Implicit geometry representation via neural operators on Riemannian manifolds for topology optimisation
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Qinglu Meng, Yingguang Li (2), Xu Liu, Gengxiang Chen, Yicheng Zhang, Lihui Wang (1)
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STC Dn, 74/1/2025, P.173
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Keywords: Design optimisation, Geometric modelling, Neural operator |
Abstract : Geometry representation, as a fundamental aspect of topology optimisation, is crucial to meet the growing demand for customised structural designs in Industry 4.0. Implicit neural representation (INR) based on neural network (NN) has emerged as a promising paradigm for geometry representation. To address the limitations of point-wise NN-based INR, this paper proposes a field-wise geometry representation via neural operators on Riemannian manifolds (NORM) for topology optimisation. Verification results demonstrate that the proposed method can not only obtain high-frequency structures with better performance, but also achieve active control of structural frequency and maintain local continuity of the optimised structure.
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Optimization of segment topology and surface form for efficient illumination with freeform lens arrays
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Atsushi Sasaki, Okiharu Kirino, Kazunori Watanabe, Anthony Beaucamp (2)
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STC Dn, 74/1/2025, P.179
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Keywords: Optical, Design method, Freeform illumination |
Abstract : Freeform optics allow holistic system design in both fields of imaging and illumination. In combination with lens arrays, they enable advanced applications such as aberration free imaging and beam redistribution from multiple irradiation sources. This paper describes an automated design method for freeform optical arrays in both tangential and normal directions. Optimizing the tangential layout of segments increases the solid angle of light collection and thus improves energy efficiency. Surface shapes are then computed by an iterative construction method based on Fermat's principle and Snell's law. Complex illumination with up-to 85% light collection is demonstrated experimentally.
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Bio-inspired multifunctional end effectors for In-space Servicing, Assembly and Manufacturing (ISAM)
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Salil Bapat, Tanvi Arey, Masters, John Vickers, Ajay P. Malshe (1)
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STC Dn, 74/1/2025, P.185
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Keywords: Biologically inspired design, Manufacturing, ISAM (In-space servicing, assembly and manufacturing) |
Abstract : This paper presents the application of crab-inspired design to develop a multifunctional robotic end effector for in-space servicing, assembly, and manufacturing. It is demonstrated that crab hub and claw-inspired design, when 3D printed using carbon fiber composite, withstand space environments for severe vibration during launch and re-entry in and from space to earth in a vessel and vacuum. Testing this design demonstrated the end effector’s versatility for tasks, including pick-and-place, twist-and-turn, and push-and-pull before and after the testing for space conditions. This study demonstrates the potential of novel bio-inspired principles to design and develop products for new commercial ISAM infrastructure.
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Customization and personalization of large language models for engineering design
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Zhoumingju Jiang, Ang Liu (2), Dawen Zhang, Xiwei Xu, Yun Dai
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STC Dn, 74/1/2025, P.191
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Keywords: Artificial intelligence, Large language model, Engineering design |
Abstract : Large language models (LLMs) are increasingly used in design and manufacturing, yet directly employing general-purpose LLMs for conceptual design often leads to unmanufacturable concepts. This paper aims to adapt general-purpose LLMs for design-specific tasks. A new framework is presented to customize a general-purpose LLM into a design-specific model based on design-relevant data and Retrieval-Augmented Generation (RAG). Another complementary framework is presented to personalize the design-specific LLM by integrating design reasoning with prompting techniques. A design experiment, using patent documents as the design-relevant data, demonstrates that customization and personalization can improve LLM effectiveness in conceptual design, especially by enhancing concept feasibility.
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Learning of design for environment with large language models: An interactive system using GPT-4
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Tatsunori Hara (2), Taisei Kawamura, Miwako Goto, Jun Ota
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STC Dn, 74/1/2025, P.197
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Keywords: Large language models, Design method, Education |
Abstract : This study explores a large language model (LLM)-based system enhancing design methodology education, focusing on design for environment (DfE). By integrating GPT-4 with DfE guidelines and a dual-loop structured learning workflow, we developed an interactive system addressing persistent challenges in design method learning. Through personalised exercises and systematic feedback, our system guided beginners in applying DfE strategies while fostering self-directed learning. Experiments involving 30 participants revealed significant improvements across Bloom's taxonomy domains, particularly when learners demonstrated sustained or developing proactiveness. This study analysed how LLM-based systems can support education for various design for X methodologies through generalizable interaction frameworks.
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Ecodesign of lithium-ion battery systems for e-mobility: a model-based LCA approach
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Téo Lavisse, Peggy Zwolinski, Daniel Brissaud (1), Rémy Panariello, Fabien Perdu
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STC Dn, 74/1/2025, P.203
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Keywords: Eco-design methodology, Lifecycle, Lithium-ion battery |
Abstract : This study presents a model-based LCA framework for the ecodesign of battery, integrating performance and durability. Combining existing designer models (usage, electrothermal, aging) with LCA leveraging a Functional Unit grounded in the battery's State of Function, this framework simulates battery aging and predicts lifespan, enabling precise LCI modelling. Applied to ecodesign strategies, the framework uncovers ecodesign opportunities overlooked by classical LCAs. Results highlight trade-offs between extending lifespan and increased energy and resource consumption, the influence of use conditions, and the benefits of multifunctional casing with improved thermal insulation. This approach is implemented in dedicated software used by CEA battery designers.
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Enabling sustainability-by-design with multi-disciplinary computer aided systems
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Iñigo Flores Ituarte, Emanuele Pagone, Amirmohammad Daareyni, Samniroshan Thayapararajah, Guido Tosello (2)
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STC Dn, 74/1/2025, P.209
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Keywords: Eco-design methodology, Design optimizatio, Computer aided design (CAD) |
Abstract : Sustainability-by-Design requires information and communication technologies (ICTs) capable of integrating design engineering, manufacturing processes, material, and sustainability considerations. Currently, methodologies for assessing environmental sustainability, such as product life cycle assessment, are often implemented too late in the design process, reducing opportunities for early intervention. Integrating environmental sustainability modeling in computer-aided systems (CAx) allows engineers to concurrently evaluate trade-offs between technical performance and environmental impact, facilitating informed decision-making during embodiment design stages. Using a prosthetic device produced via material jetting additive manufacturing as case study, we demonstrate the transformative role of advanced CAx tools capable of analyzing trade-offs among competing objectives.
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Sim2Know: new paradigm of digital twins to design and inform human-centric knowledge system
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Bingbing Li, Haolin Fan, Zhen Fan, John Ahmet Erkoyuncu (2), Hong-Chao Zhang (1), Haihong Huang
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STC Dn, 74/1/2025, P.215
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Keywords: Digital twin, Artificial intelligence, Human-centric knowledge |
Abstract : The novel framework, Sim2Know, tackles two major challenges in adaptively designing and informing a human-centric knowledge system: the lack of labeled real-world training data and the difficulty of capturing implicit knowledge. First, a digital twin demonstrator is developed to generate high-quality synthetic training data. Next, we propose a hybrid training approach that combines transfer learning from pre-trained self-supervised models with synthetic data augmentation, achieving a precision rate of 90.31% in identifying 11 essential human action patterns in metal additive manufacturing. Finally, the human-centric knowledge system is designed to capture implicit knowledge through contextualizing human machine interaction beyond explicit domain knowledge.
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STC E |
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Electrochemical finishing of internal channels in additively manufactured components using in-situ channel-conformal sacrificial tool electrodes
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Xiaoming Duan, Kun Zhang, Xiaodong Yang, Masanori Kunieda (1)
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STC E, 74/1/2025, P.221
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Keywords: Electro chemical machining (ECM), Finishing, Additively manufactured channel |
Abstract : This paper aims to finish efficiently the surface of internal channels in additively manufactured parts. A novel electrochemical finishing (ECF) method was developed to finish curved channels of 5.8 mm in diameter. The tool electrode required for ECF was additively manufactured simultaneously with the internal channel. The finishing efficiency was significantly high because the electrolysis current flows uniformly at the same time along the channel. Furthermore, the tool electrode was rapidly removed through electrochemical dissolution by reversing the polarity after ECF. The gradient in material removal efficiency along the electrolyte flow ensures the stable removal of the tool electrode.
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Segmented 5-axis flank milling: a fast electrical discharge milling strategy for diffuser-shaped film cooling holes
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Bin Li, Zhuohang Yao, Huanyu Lu, Qiang Gao, Juncheng Lu, Xuecheng Xi, Wansheng Zhao (2)
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STC E, 74/1/2025, P.227
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Keywords: Electrical discharge machining (EDM), Milling, Diffuser-shaped film cooling hole |
Abstract : This study presents a segmented 5-axis flank milling strategy for fast ED-milling of diffuser-shaped film cooling hole on turbine blades. The proposed method divides the plunge depth into several segments while maintaining flank milling. It combines the benefits of layered fast ED-milling and multi-axis flank fast ED-milling while avoiding complex electrode wear compensation or coarser sidewall surface. The mathematical principles and discretization algorithm for typical ruled surfaces are established to generate 5-axis milling paths for various shaped diffusers. The experimental results demonstrate that the proposed method achieves high geometric accuracy and surface quality, along with significant improvements in machining efficiency.
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Mitigating thermal damages in the electrochemical discharge machining of carbon fiber-reinforced polymer
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Murali Sundaram, Yu-Jen Chen, K.P. Rajurkar (1)
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STC E, 74/1/2025, P.233
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Keywords: Composite, Material removal, Thermal effect |
Abstract : This study investigates the influence of three distinct configurations of the electrochemical discharge machining (ECDM) process on the thermal damages in the machining of carbon fiber-reinforced polymer composite material. High-energy direct sparks and lower-energy ambient sparks generated by these configurations were found to be more effective in improving the machining quality during the material removal of carbon fibers and polymers respectively. The experimental results show that higher feed rates near the workpiece edge significantly reduced the heat-affected zone (HAZ) and anisotropic thermal damage due to better heat dissipation into the electrolyte and optimal utilization of the direct sparks.
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Spatially resolved Wire EDM discharge analysis for dynamic part strength evaluation
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Andreas Klink (2), Lukas Welschof, Kai Osswald, Tim Herrig
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STC E, 74/1/2025, P.239
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Keywords: Wire EDM, Monitoring, Bending Fatigue |
Abstract : Wire Electrical Discharge Machining (Wire EDM) is particularly suitable for producing high-precision geometries in demanding materials such as the manufacture of profile grooves in turbine disks. Advanced monitoring nowadays allows the time and spatially resolved in-process discharge analysis. Therefore, in this paper the machining of Inconel 718 parts is fundamentally studied and the resulting surface integrity in terms of roughness and residual stresses is evaluated for main and trim cut strategies. Finally, the resulting bending fatigue performance is characterized in a zone resolved and overall averaged analysis along the workpiece height and compared to reference results of alternative machining approaches.
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Removal mechanism of diamond/Al composites in Blasting Erosion Arc Machining
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Lin Gu (2), Lijie Jiang, Kelin Li, Xiaoka Wang
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STC E, 74/1/2025, P.245
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Keywords: Material removal, Electrical discharge machining (EDM), Metal matrix composite |
Abstract : Diamond/Al composites are promising materials for thermal management, but the presence of diamond particles makes them extremely difficult-to-cut. To address this challenge, blasting erosion arc machining (BEAM) is suggested for its high efficiency. The removal mechanism, particularly the influence of diamond particles, was first studied through magnetohydrodynamics and heat transfer simulations. Further analysis revealed how differences in the thermal properties between the reinforcements and the matrix result in distinct solid-liquid-gas phase transitions. The debris morphology and composition were analyzed to further clarify the removal mechanism. Experiments confirmed the high-efficiency machining performance of BEAM in diamond/Al composites.
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Efficient processing with removal of modification in ultrashort pulse laser processing of diamond
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Reina Yoshizaki, Shogo Kitamura, Yuta Teshima, Masayuki Nakao (1)
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STC E, 74/1/2025, P.251
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Keywords: Laser micro machining, Diamond, Surface modification |
Abstract : The demand for higher precision and efficiency in the ultrashort pulse laser processing of diamonds is growing as the industrial applications of diamonds expand. However, surface modification layers generated during laser irradiation negatively impact processing efficiency and remain difficult to actively control. This study improves processing efficiency by proposing and validating a two-step method that removes the surface modification layer after each pulse. Removing the modified layer increases the material removal volume and provides new insights into the impact of the modified layer on processing outcomes, laying the groundwork for future advancements in the ultrashort pulse laser processing of diamonds.
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Enhanced Magnet-aided Laser Induced Plasma Micromachining (E-MLIP) for expanded geometric capabilities
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Rajiv Malhotra, Anandkumar Patel, Kiarash Naghavi Khanghah, Hongyi Xu / A. Donmez (1)
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STC E, 74/1/2025, P.257
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Keywords: Laser micro machining, Plasma, Monitoring |
Abstract : Laser Induced Plasma Micro Machining (LIPMM) focusses a laser inside a liquid to create plasma that is used for micromachining with superior multi-material capability. This work subjects the plasma to a novel magnetic field to realize atypically simultaneous enhancement of feature resolution, feature depth and Material Removal Rate beyond the limitations of LIPMM and Direct Laser Ablation. A new physics-based model is established to uncover the mechanism behind this enhancement. Further, an acoustics-based approach is created for quantitative in-situ prediction of feature dimensions while considering unknown phenomenological disturbances in the material removal zone, a capability that lies beyond the state-of-the-art.
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Improvement of anodic oxide film characteristics of Al-Cu alloy by refinement of IMCs with large-area electron beam irradiation
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Togo Shinonaga, Ayano Sebe, Masanori Taniguchi, Toshinori Fujii, Akira Okada (1)
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STC E, 74/1/2025, P.263
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Keywords: Electron beam, Aluminum, Anodic oxide film |
Abstract : Al-Cu alloy has been widely applied to automobile products due to its light weight and high strength, but pitting corrosion easily occurs due to intermetallic compounds (IMCs) in Al-Cu alloy. Anodizing process has been conventionally performed to improve the corrosion resistance of Al-Cu alloy surface. However, IMCs in Al-Cu alloy lead to defects in anodic oxide film. In this study, refinement of IMCs in Al-Cu alloy surface by large-area EB irradiation was proposed. Experimental results show that reflectance and corrosion resistance of anodic oxide film formed on Al-Cu alloy surface are improved by refinement of IMCs with the EB irradiation.
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Mechanism and dynamics of transient and selective laser processing revealed through high-speed observation combined with precision timing control
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Yusuke Ito, Guoqi Ren, Naohiko Sugita (1)
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STC E, 74/1/2025, P.269
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Keywords: Laser micro machining, Glass, Sapphire |
Abstract : Transient and selective laser (TSL) processing has attracted attention as an ultrafast, high-precision microfabrication method for glass. In TSL processing, the material is locally excited, and the excited region is selectively removed at ultra-high speed. However, its processing mechanism, dynamics, and applicability to other materials remain unclear. In this study, we visualized the processing phenomena using sub-microsecond-scale ultrafast imaging and nanosecond-scale precise timing control. We revealed that the process is triggered by bandgap shrinkage following electron–phonon relaxation. Furthermore, we demonstrated that this method enables the processing of sapphire—a large-bandgap material—at speeds 25,000 times faster than conventional methods.
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Study on field emission characteristics of carbon nanotube arrays patterned via laser welding of dissimilar materials
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Hung-Yin Tsai, Yi-Hung Chen, Kuan-Ching Wang, Paul W. Leu, Ming C. Leu (1)
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STC E, 74/1/2025, P.275
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Keywords: Laser welding, Chemical Vapor Deposition (CVD), Carbon nanotube (CNT) |
Abstract : This paper describes a new method of growing carbon nanotube (CNT) arrays using laser welding of a catalyst metal onto the surface of a quartz substrate, followed by CNT growth through the chemical vapor deposition (CVD) process. A major advantage of this method is its ability to pattern the catalyst before growing the CNTs, thus allowing for the formation of CNTs at specific locations. The laser pre-treatment method minimized structural damage to CNTs in comparison to the laser post-processing method, achieving a lower ID/IG value of 0.72 in Raman spectroscopy analysis. Using hexagonally patterned CNT arrays on quartz, we achieve a field emission current density exceeding 1.3 mA/cm2 with a reduced turn-on field of 1.85 V/μm, representing a 25% improvement over filled-line patterns.
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Polishing of fused silica by laser-enhanced plasma at the atomic and close-to-atomic scale
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Peng Lyu, Jiyu Pan, Ze Liu, Fengzhou Fang (1)
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STC E, 74/1/2025, P.281
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Keywords: Plasma, Laser, Atomic and Close-to-atomic Scale Manufacturing (ACSM) |
Abstract : Fused silica is widely used in optical systems such as imaging devices, spectrophotometers and telescopes, where surface quality and morphology play critical roles in product performance. To address these stringent requirements, this study proposes a novel laser-enhanced plasma method. This approach integrates a controlled laser beam into plasma processing, which locally activates the fused silica and increases the concentration of plasma active particles by ~15%. The technique facilitates both surface roughness and morphology, achieving a surface roughness of 0.28 nm in Sa and a shape error of 7.64 nm in RMS.
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Printability assessment and modelling for process optimization of 3D Aerosol Jet® printed high aspect ratio microstructures
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Elisabetta Ceretti (2), Mohit Sharma, Eleonora Ferraris (2), Paola Serena Ginestra, Miriam Seiti
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STC E, 74/1/2025, P.287
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Keywords: Additive Manufacturing, Optimization, High-Aspect-Ratio. |
Abstract : The printability assessment of high-aspect-ratio structures in additive manufacturing is critical for ensuring dimensional accuracy and functional properties. This study proposes a method to evaluate print quality by quantifying metrics, including shape fidelity and line edge quality, using advanced imaging and predictive analysis. A printability index is developed to relate these metrics to process parameters, here applied to Aerosol Jet® Printing. By validating structures’ quality and optimizing parameters, the index effectively improves process stability, reduces defects, and enhances structural precision. This approach provides a robust tool for process optimization, ensuring consistent results in complex high-aspect-ratio designs, further advancing printing scalability and reproducibility
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Effect of layer thickness in laser powder bed fusion of HWTS 50 hot work tool steel
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Sasan Dadbakhsh, Sinesh Vadakkekkara, Ashik Mansingh Anila, Lorena Emanuelli, Massimo Pellizzari, Faraz Deirmina / B. Lindström (1)
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STC E, 74/1/2025, P.293
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Keywords: Additive Manufacturing, Optimization, Tool steel |
Abstract : This work optimises and analyses the processing of a new lean tool steel (Osprey® HWTS 50), using laser powder bed fusion (PBF-LB) at 80°C preheating and different layer thicknesses (20 µm vs. 40 µm). Full density is reached via a higher volumetric energy density (VED) for the lower layer thickness. After optimising contours, reducing surface roughness and ensuring no microcrack formation, the tensile properties were rather comparable in both cases (UTS ~ 1500MPa, elongation ~ 10-12%). However, yield strength, hardness and residual stresses were slightly higher for the lower layer thickness. The geometrical freedom for intricate features was nevertheless comparable.
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Laser powder directed energy deposition and substrate-free single layer powder bed fusion under micro- and lunar gravity conditions
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Ludger Overmeyer (2), Marvin Raupert, Matthias Pusch, Tjorben Griemsmann, André Katterfeld, Christoph Lotz
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STC E, 74/1/2025, P.297
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Keywords: Additive manufacturing (AM), Directed energy deposition (DED), In-Space Manufacturing (ISM) |
Abstract : In-Space Manufacturing (ISM) needs material-efficient processes or the usage of locally available resources. This article presents two successfully applied approaches: Laser Powder Directed Energy Deposition (LP-DED) realized in microgravity on Earth for the first time using Ti-6Al-4V and substrate-free single layer powder bed fusion (PBF) under lunar gravity using LX-I50 regolith simulant. The Einstein-Elevator, a third-generation drop tower, is used to simulate the environmental conditions of space regarding gravity. The research results confirm the feasibility and open up new perspectives for space research, particularly concerning resource-efficient manufacturing technologies in future missions.
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Circular manufacturing of binder jetting additive parts from Ti-6Al-4V machining chips
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Debajyoti Bhaduri, Karan A. Baramate, Soumya Gangopadhyay, Thomas E. Davies / T. H.C. Childs (1)
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STC E, 74/1/2025, P.303
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Keywords: Binder jetting, Titanium, Ball milling |
Abstract : The viability of using ball milled (BM) Ti-6Al-4V machining chips for fabricating parts by binder jetting (BJT) additive manufacturing is reported. The built parts’ density, roughness, microhardness and compressive strength are compared with BJT parts made from gas atomised (GA) powder. Sintered BM and GA parts exhibit comparable relative density (93-95%), while microhardness of the former is almost twice of the latter. Equiaxed grains with greater β-phase fraction are observed in the BM parts’ microstructure. The BM compression test pieces exhibit brittle fracture due to greater strain hardening of the BM particles, compared to the plastic deformation of the GA specimens.
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Laser powder bed fusion process parameters for the fabrication of unsupported overhang structures of metamaterial lattices
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Wessel W. Wits (2), Camill de Vos, Maria Montero-Sistiaga, Marc de Smit
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STC E, 74/1/2025, P.309
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Keywords: Additive manufacturing (AM), Powder bed fusion (PBF), Metamaterials |
Abstract : Laser powder bed fusion of unsupported overhang structures, required for metamaterial lattices, are difficult to manufacture. In this study, process parameters are experimentally determined to successfully fabricate auxetic re-entrant metamaterial structures. Due to the support-less printing, higher linear energy densities compared to contour and hatch scanning are required to build continuously solidified overhang structures. Simulation results show that the melt pool width and in particular the length are enlarged, promoting loose powder attachment by denudation and balling. Auxetic re-entrant metamaterials are successfully fabricated. Impact tests show good mechanical performance and better energy absorption compared to previous studies.
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Design and analyses of powder deposition, gas flow, and productivity for a rotary laser powder bed fusion system
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Markus Bambach (2), Michael Robert Tucker
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STC E, 74/1/2025, P.315
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Keywords: Additive manufacturing, Powder bed fusion, Machine |
Abstract : This study presents the design of a novel rotary PBF-LB/M machine where the recoater and gas system rotate synchronously with laser exposure. Unlike previous setups, the rotating nozzle covers only part of the powder bed, enabling higher localized gas velocities. CFD simulations indicate that a fine-mesh square grid improves flow uniformity with minimal powder disturbance. An angled recoater design supports stable rotary powder deposition. Trial builds, in-process measurements, and analyses of timing and powder efficiency demonstrate the system's effectiveness for annular parts, offering a significant speed advantage over rectilinear designs.
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Comparison of three hybrid metal additive-subtractive manufacturing processes
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Christian Baumann, Manisha Yerranagu, Weijun Zhang, Aishwarya Deshpande, Severin Maier, Stefan Gössinger, Masakazu Soshi, Friedrich Bleicher (1), Frank E. Pfefferkorn (1)
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STC E, 74/1/2025, P.321
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Keywords: Additive manufacturing (AM), Hybrid manufacturing, Stainless steel |
Abstract : The objective of this work is to compare three different hybrid metal additive-subtractive manufacturing processes to enable decision-making and future research. This was achieved by producing the same artifact out of 316L stainless steel with - Friction Surfacing, Wire Arc Additive Manufacturing, and Laser Powder Directed Energy Deposition. Key process outcomes including cycle time, resource consumption, distortion, energy consumption, microstructure, hardness, and tensile strength were analyzed. It was observed that: Friction Surfacing demonstrates higher hardness due to its solid-state nature, Wire Arc Additive Manufacturing offers lower cycle times and resource consumption, and Directed Energy Deposition provides near net shape geometries.
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Accelerated degradation of 3D-printed PETG bone–tissue scaffolds via geometrical control
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Hussein Mishbak, Mohamed H. Hassan, Evangelos Daskalakis, Abdalla M. Omar, Dino M. Freitas, Wajira Mirihanage, Paul Mativenga (2), Prasad Potluri, Paulo Bartolo (1)
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STC E, 74/1/2025, P.327
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Keywords: 3D printing, Biomedical, Design optimisation, Degradation |
Abstract : Scaffolds play a key role in bone repair and should have a degradation rate that matches the rate of bone regeneration. However, the slow degradation of bone tissue scaffolds is a major challenge. This research investigated the degradation rate of Polyethylene terephthalate glycol (PETG) bone-tissue scaffolds printed with different lay-up patterns (0/45, 0/60/120, and 0/90). Degradation kinetics were explored using design-informed processing conditions, considering variations in the printing path length, crystallinity and fibre contact points. The findings revealed that changing scaffold lay-up increased the degradation rate by up to 50% while maintaining compressive modulus. The research contributes a new and novel material-independent approach for controlling scaffolds degradation rate and mechanical performance.
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Characterization of the high-pressure suspension jet for efficient cutting and abrasive circularity
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Florian Morczinek, Martin Dix (3), Rafael Wertheim (1)
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STC E, 74/1/2025, P.333
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Keywords: Abrasive Waterjet Machining, Energy Efficiency, Particle Flow |
Abstract : To optimize the workpiece removal process and maximize the fraction of reusable abrasive particles, it is necessary to ascertain the characteristics of the high-pressure suspension jet process, including the kinetic energy of the particles in the jet. In this study, the particle velocity and the change in their size were measured and analyzed. It was found that due to breakage the average particle size decreases by up to 35% during the acceleration process in the nozzle. The results showed that the particle size has insignificant influence on particle velocity, while the kinetic energy of an average particle decreased by up to 72%.
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STC F |
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Exploring the feasibility of a closed-loop industrial symbiosis link through Friction Stir Extrusion-based Additive Manufacturing
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Kirill Kalashnikov, Davide Campanella, Giuseppe Ingarao, Gianluca Buffa, Fabrizio Micari, Livan Fratini (1)
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STC F, 74/1/2025, P.339
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Keywords: Additive manufacturing (AM), Recycling, Friction stir welding |
Abstract : A novel approach combining friction stir extrusion-based chips recycling and additive manufacturing was investigated to assess its suitability for a closed-loop industrial symbiosis. Recycled wires made from heat-treatable aluminum alloy AA6082 were used as a feedstock for solid-state additive manufacturing. The macrostructure and microstructure of the material were analyzed to reveal the layer formation mechanics and their influence on the micro and macro mechanical properties of the build. The produced material is characterized by a unique temper providing mechanical properties close to AA6082-T4. Finally, the proposed approach was compared with competitive technologies in terms of deposition rate and energy consumption.
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Sub-Zero temperature blanking of non-oriented electrical steels
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Enrico Simonetto, Stefania Bruschi (1), Andrea Ghiotti (1), Agnes Schrepfer, Wolfram Volk (1)
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STC F, 74/1/2025, P.345
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Keywords: Blanking, Steel, Cryogenic |
Abstract : Blanking at sub-zero temperatures using liquid nitrogen is presented as an innovative method for cutting non-oriented electrical steel (NOES) to reduce the plastic deformation required for separation and minimize microstructural changes that could impact the sheet's characteristics. Three process temperatures – room temperature, -50 °C, and -100 °C – were investigated, and the results were evaluated in terms of cut edge quality, microstructural features, and hardness evolution. The results demonstrated a significant reduction in the plastically deformed zone and hardness variation at the cut edge, accompanied by decreased microstructural misorientation, highlighting this method's potential to minimize the drawbacks of conventional blanking.
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Consideration of Bauschinger effect based on a reduced texture approach for improved springback prediction with computational efficiency
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Donghwan Noh, Jeong Whan Yoon (2) / D.Y. Yang (1)
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STC F, 74/1/2025, P.351
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Keywords: Metal forming, Springback, Reduced texture approach |
Abstract : This study introduces a reduced texture approach to efficiently describe the plastic behavior of AA6022-T43. By reducing the number of orientations in Finite Element (FE) analyses, the reduced texture approach improves computational efficiency while accurately predicting plastic responses. The approach calibrates a small number of crystallographic orientations using mechanical test results. By incorporating a kinematic hardening model, it captures Bauschinger effect, transient behavior, and permanent softening. Its predictive accuracy is also validated in springback, a critical challenge in sheet metal forming. The results confirm its potential as a computationally efficient alternative to continuum models for large scale engineering problems.
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Mechanisms driving accelerated formability recovery in forming of ultra-thin titanium sheets with intermediate electropulsing treatment
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Junying Min, Xianglu Zhang, Bo Chen, Xiaolong Ma / D. Banabic (1)
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STC F, 74/1/2025, P.357
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Keywords: Forming, Micro structure, Electropulsing treatment |
Abstract : Formability recovery resulting from static recovery and recrystallization of 0.1 mm CP-Ti sheets can be achieved in remarkably reduced time (≤2 sec) under electropulsing treatment (EPT), yet the underlying mechanisms remain unclear. This study experimentally confirms that the formability recovery of pre-deformed CP-Ti is predominated by EPT temperature with existence of a threshold for its onset at approximately 623 K. Characterization using electron backscatter diffraction suggests that the accelerated recovery by EPT is primarily attributed to the activation of dislocation climb, increased recrystallization nucleation sites, and enhanced grain boundary migration, which is attributed to the “target effect” of EPT.
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Mold liners produced by incremental sheet forming
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Putong Kang, Brett Wadman, Kornel Ehmann, Jian Cao (1)
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STC F, 74/1/2025, P.363
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Keywords: Forming, Molding, Prototyping |
Abstract : This study explores Incremental Sheet Forming (ISF) to fabricate mold liners as part of a newly proposed molding system for small-scale applications. A modified toolpath strategy, leveraging the tooltip geometry and feature skeleton, enabled the creation of high-quality features. The rotating forming tool introduced wavy surface textures, enhancing the functionality of the molded products. Polydimethylsiloxane (PDMS) molded with ISF-formed liners demonstrated good dimensional accuracy and smooth surface finishes. Compared to stereolithography (SLA)-printed liners, ISF-formed liners offered easier demolding and broader material compatibility. Future work will address high-pressure applications and more complex mold designs to expand industrial applicability.
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Hybrid modelling predicting forming behaviour with variations in AlMgSi1 alloys
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Kristian Martinsen (3), Thawin Hart-Rawung, Jon Holmestad, Johan Andreas Stendal, Sverre Gulbrandsen-Dahl, Ole Runar Myhr / F. O. Rasch (1)
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STC F, 74/1/2025, P.369
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Keywords: Metal Forming, Machine Learning, Hybrid Modeling |
Abstract : This paper shows how hybrid modeling combining a physics-based Precipitation Model and a data-driven Gaussian Process Regression model can be used to predict flow stress curves of different variants of AlMgSi1 alloys. The approach can be a step towards a methodology to manage higher variability in input material, such as remelted contaminated post-consumer aluminum scrap. Data from laboratory compression tests of six different compositional variations of AlMgSi1 with different contents of Si, Cu, and Mg was used. The proposed hybrid model aligns well with experimental results both within the training data range and inputs beyond the training range.
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Slipline solution to asperity deformation under combined high normal pressure and subsurface deformation
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Chris V. Nielsen (2), Paulo A.F. Martins (1), Niels Bay (1)
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STC F, 74/1/2025, P.375
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Keywords: Metal forming, Tribology, Slipline solution |
Abstract : A new set of slipline fields, along with a corresponding calculation procedure, offers an analytical solution to the flattening of asperities under high normal pressure and subsurface deformation. This new solution integrates existing slipline fields for asperity flattening at high normal pressures with those related to indentation and provides a statically admissible transition to uniform subsurface deformation under plane strain conditions. The calculation procedure effectively manages the transition from one slipline field to another, accounting for increments in both the real contact area ratio and the longitudinal strain associated with subsurface deformation. The new solution is validated against numerical simulations.
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Hot extrusion of aluminium-polymer profiles with axially-graded cross-sections
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Yannis P. Korkolis, Patrick Schindler, Enno Henn, Johannes Gebhard, Markus Stommel, A. Erman Tekkaya (1)
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STC F, 74/1/2025, P.381
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Keywords: Extrusion, Process control, Composite |
Abstract : Feeding of a pressurized polymer melt into a hollow aluminium profile during extrusion enables the production of solid hybrid profiles in a single process step. Controlling the process by the pressure or the volumetric-flow-rate of the polymer are compared. Process limits are identified as the minimum polymer pressure to ensure profile filling and the maximum polymer pressure to prevent bursting. Within the derived process window, experiments demonstrate the ability to produce a constant or an axially-graded cross-section, as well as form-fit elements along the length. An analytical approach for predicting the resulting internal diameter of the profile is proposed.
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Rotary tube flaring using a conical punch with grooves for high forming limit and productivity
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Shohei Kajikawa, Kiwamu Uchida, Takashi Kuboki (1)
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STC F, 74/1/2025, P.387
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Keywords: Metal forming, Cold forming, Flaring |
Abstract : This paper presents rotary tube flaring using a conical punch with grooves to achieve a high flaring limit and productivity. The grooved punch improves the flaring limit by suppressing bucking because it reduces the axial load as the tube contacts the punch intermittently. The effects of groove size and number on formability were investigated using tubes of aluminium alloy AA1070 and copper alloy C1220. The limit flaring ratio increased by up to 2.8 times compared to that of conventional press forming when the groove size and number were appropriate. The appropriate groove size varied depending on the tube material used.
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Tailored multi-material systems with thickness distribution by orbital forming
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Arnold Harms, Simon Wituschek, Michael Lechner, Marion Merklein (1)
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STC F, 74/1/2025, P.393
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Keywords: Mechanical joining, Orbital forming, Multi-material systems |
Abstract : The utilization of multi-material systems is becoming increasingly relevant for future production technologies with regard to lightweight design and higher functional integration. Furthermore, improvements demand for new approaches that involve the integration of local material accumulation and a joining operation in a single step using an orbital forming process. The investigations are carried out on the basis of a demonstrator joining a steel ring and an aluminum blank. This involves the analysis of the mechanisms for joint formation, the identification of process limits, and the determination of a process window for the manufacturing of an adequate hybrid component.
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Advanced double-flush riveting for multistage forming tools
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Carlos M.A. Silva, João P.M. Pragana, Rui F.V. Sampaio, Ivo M.F. Bragança, Paulo A.F. Martins (1)
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STC F, 74/1/2025, P.399
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Keywords: Cold forming, Joining, Multistage tools |
Abstract : This paper presents a novel double-flush riveting process for creating lap joints in sheet metal parts. The process involves punching, forging, and shaving to produce countersunk holes with precise geometry, followed by compression of cylindrical rivets into the holes of two overlapped sheet parts to create form-closed mechanical interlocks. Experimental and numerical analyses examine the influence of the primary process parameters on interlock quality and required forming and destructive forces. The investigation is a step forward in joining technology by offering a simple alternative to welding, bonding, and mechanical joining, with seamless integration into multistage forming tools.
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A new joint with versatile properties based on a Reuleaux triangle geometry
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Christian Steinfelder, Clemens Acksteiner, Alexander Brosius (2)
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STC F, 74/1/2025, P.405
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Keywords: Joining, Forming, Property adjustment |
Abstract : Non-rotationally symmetrical joints can have different properties that can be controlled by the joint orientation. This hypothesis is tested using a Reuleaux triangle joint geometry. A tool design is carried out, followed by a numerical sensitivity analysis of the tool geometry. Initial tools were manufactured for experimental investigations and then adapted based on the findings of the sensitivity analysis. The joints are characterized by micrographs, 3D scans, shear tensile tests, head tensile tests and three-point bending tests and compared with a round geometry. The analysis confirms the hypothesis. Thus, joints with adaptable properties can be produced with one tool set.
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Towards large-scale production of improved magnetic flux guidance structures in non-grain-oriented electrical steel
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Phillip Stöcks-Morgan, Tobias Neuwirth, Achref Douiri, Simon R. Sebold, Anders Kaestner, Christoph Hartmann, Nora Leuning, Michael Schulz, Wolfram Volk (1)
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STC F, 74/1/2025, P.411
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Keywords: Residual Stress, Electric Vehicle, Press |
Abstract : Modern synchronous electric drives require magnetic anisotropy in their rotor, manufactured from non-oriented electrical steel. Conventionally, flux barriers are placed on electrical steel sheets by removing the material, creating small recesses. While the approach is magnetically effective, the rotor is mechanically weakened. Embossed flux barriers offer an approach to stiffen the rotor mechanically, increasing efficiency. The required micro-embossing was successfully produced on an industry-grade press for the first time. Magnetic characterisation of the samples using neutron grating interferometry and a single sheet tester shows that the novel technology is transferrable from the laboratory frame to large-scale industrial manufacturing processes.
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STC G |
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Materials removal mechanism in laser-assisted grinding of SiC fibre reinforced Titanium alloy composite
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Dongdong Xu, Tiancheng Ai, Zifu Shen, Shuan Ma, Md Saddam Hossen, Zhirong Liao (2)
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STC G, 74/1/2025, P.417
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Keywords: Laser-assisted grinding, Metal matrix composite, Surface integrity, Titanium composite |
Abstract : Silicon carbide fibre-reinforced titanium matrix composites are promising materials for lightweight and high-strength applications. However, their unique properties make them extremely difficult to machine. The present investigation proposes a laser-assisted grinding method to address this challenge and reveals distinct deformation mechanisms of the reinforced SiC fibres and titanium matrix by analysing the monitored machining process, surface properties, subsurface microstructure, and nanoscale deformation characteristics. It achieves improved surface integrity and enhanced machinability, attributed to the softening effect induced by additional thermal loads. This phenomenon transitions the SiC fibres from brittle states to semi-ductile conditions, facilitating fracture and improving overall machinability.
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Consideration of thermally induced material modification depth for grinding process cycle design
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Gerrit Kuhlmann, Lars Langenhorst, Tobias Hüsemann, Carsten Heinzel (2)
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STC G, 74/1/2025, P.423
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Keywords: Grinding, Surface integrity, Thermal effect |
Abstract : The effects of varying grinding power and contact time on surface layer modifications in grinding are investigated in terms of i) the onset of white layer formation and ii) areas of similar tempering zone depths. An empirical equation derived from single-stage grinding experiments is used to predict the resulting tempering zone depth for multi-stage grinding experiments. Tempering zones were deliberately allowed during roughing and subsequently removed by further process steps. The potential of reducing process main time by an optimized grinding process cycle design allowing tempering zones in the first cuts is demonstrated.
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Electromagnetic field-assisted ultra-precision grinding of single-crystal Ni-based superalloy
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Te Zhao, Suet To (2), Tengfei Yin, Xiangqian Jiang (1)
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STC G, 74/1/2025, P.429
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Keywords: Grinding, Nickel alloy, Electromagnetic field-assisted |
Abstract : This paper proposes the integration of an electromagnetic field into the ultra-precision grinding process to improve the machinability of the single-crystal nickel-based superalloy. The effects of the magnetic flux intensity on the grinding wheel vibration and surface integrity were investigated through grinding experiments. The results show that the wheel vibration amplitude was reduced by 45.82% by applying the electromagnetic field. The arithmetic mean height (Sa) and the maximum height difference (Sz) were decreased by 71.09% and 67.69% , respectively, in the optimal condition, which demonstrates the effectiveness of the proposed electromagnetic field-assisted ultra-precision grinding process.
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Kinetic analysis of workpiece rotation behavior during double-sided polishing
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Urara Satake, Yuta Seguchi, Toshiyuki Enomoto (1)
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STC G, 74/1/2025, P.435
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Keywords: Polishing, Modelling, Double-sided machining |
Abstract : Unique clamping mechanism adopted in double-sided polishing (DSP) enables free rotation of workpieces, which is critical for achieving uniform material removal. However, the DSP process has long faced the issue of non-rotating workpieces, resulting in tapered shapes—an issue particularly relevant to silicon wafer polishing. In this study, a kinetic analysis is conducted to investigate workpiece rotation during DSP and to clarify the mechanism underlying tapering. This analysis identifies key variables governing rotational speed and primary factors contributing to workpiece nonrotation. These findings are validated experimentally, and a practical approach to preventing tapering is proposed.
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Atomic-level flat polishing of polycrystalline diamond by combining plasma modification and chemical mechanical polishing
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Song Yuan, Benny C.F. Cheung (1), Alborz Shokrani (2), Zejin Zhan, Chunjin Wang
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STC G, 74/1/2025, P.441
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Keywords: Diamond, Plasma, Polishing |
Abstract : This paper presents an atomic-level flat polishing method based on hydroxyl (•OH) oxidation combining plasma modification and chemical mechanical polishing (CMP) of polycrystalline diamond (PCD). The PCD surface was firstly modified using •OH generated by He-based H2O2 plasma leading to the formation of an approximately 30 nm thick uniform oxidation layer on the PCD surface composed of carbon-oxygen mixed layer and oxygen-rich layer. Reactive force field molecular dynamics (ReaxFF MD) simulations explained the plasma modification mechanism. The modified layer was then removed using CMP resulting in an atomic-level flat surface with arithmetical mean height (Sa) of 0.366 nm.
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High-efficiency modification mechanism of GaN(0001) in plasma-assisted polishing using hydrogen plasma
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Tong Tao, Rongyan Sun, Yuji Ohkubo, Kazuya Yamamura (2)
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STC G, 74/1/2025, P.447
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Keywords: Surface modification, Polishing, GaN, Hydrogen plasma, Modification mechanism |
Abstract : Gallium nitride (GaN) is a promising material for high-power, high-frequency electronic devices. Plasma-assisted polishing (PAP) process achieved high-quality surface polishing of GaN by combining plasma modification with the removal of modified layer using soft abrasives. In PAP, the modification rate directly determines the overall PAP efficiency. This study replaced traditional oxidative plasma with vacuum H₂ plasma, which has a smaller atomic diameter and reducing properties, to improve modification efficiency. By thoroughly investigating the mechanism of H₂ plasma modification on GaN surface and optimizing the relevant process parameters, efficient and controllable GaN surface modification was achieved while suppressing surface roughness deterioration.
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Robust estimation of chip clogging with supervised learning using tool surface image
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Tatsuya Furuki, Koichi Nishigaki, Takashi Suda, Hirofumi Suzuki (1)
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STC G, 74/1/2025, P.453
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Keywords: Machine learning, Diamond coating, Chip |
Abstract : The evaluation of chip clogging on the bottom surface of diamond-coated drills is traditionally performed through visual inspection by technicians. This study replicates this sensory evaluation by constructing a clogging discriminator using supervised machine learning with drill surface images. Image features ensuring high discrimination accuracy while minimizing wear or coating influence were identified. Verification results demonstrated that the histogram of oriented gradients and cumulative distribution function of luminance effectively construct a robust clogging discriminator, regardless of surface conditions. This method enables efficient clogging assessment, contributing to practical applications and improved drill performance evaluation in industrial settings.
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Ultrasonic assisted abrasive nano-blasting
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Ashwani Pratap, Wule Zhu (2), Mori Yuka, Anthony Beaucamp (2)
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STC G, 74/1/2025, P.459
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Keywords: Polishing, Ultrasonic, Abrasive deagglomeration |
Abstract : This research introduces abrasive nano-blasting using fine abrasive particles. Fine abrasive particles are difficult to use in abrasive blasting due to tendency of forming agglomerates caused by prevalent surface forces. The pressure gradient and streaming effect of ultrasonic vibration is utilized to break the abrasive agglomerates before impacting the workpiece for polishing. It could be observed through simulations that the pressure gradient to overcome the adhesive forces and breaking the agglomerates can be theoretically achieved. Polishing experiments revealed that acoustic streaming inside the ultrasonic cavity also improved uniform surface generation with up to 67% reduction in surface roughness Sa.
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Mitigation of Cu dishing in chemical mechanical polishing using micro-structured pads
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Seulah Park, Sukkyung Kang, Dong Geun Kim, Sanha Kim (2)
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STC G, 74/1/2025, P.465
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Keywords: Polishing, Semiconductor, Surface analysis |
Abstract : Dishing is a critical defect in chemical mechanical polishing (CMP) that affects the mechanical reliability and electrical performance of hybrid bonding interfaces in semiconductor packaging. This study explores that micro-structured pads with well-defined asperity design can minimize CMP dishing. A theoretical model identifies asperity area, height variation, and modulus as key factors influencing contact pressure and dishing. Experimental results validate the model, demonstrating a 69% reduction in dishing with a soft cylindrical pad compared to a commercial pad. This improvement is attributed to increased real contact area and uniform pressure distribution due to minimized height variation and material compliance.
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A glycerol-based slurry for Cs2LiYCl6 crystal polishing
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Jiang Guo, Ankang Yuan, Jing Li, Zhe Yang, Zili Zhang, Lin Li (1)
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STC G, 74/1/2025, P.471
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Keywords: Polishing, Roughness, Cs2LiYCl6 crystal |
Abstract : A glycerol-based slurry was developed for the precision polishing of Cs₂LiYCl₆ (CLYC) crystals. Glycerol was chosen as the base liquid to minimize excessive deliquescence, while ethanol was added to enhance the slurry's fluidity. By incorporating a small amount of deionized water and SiO₂ abrasives, the slurry effectively balances deliquescence with mechanical material removal. The material removal mechanism was elucidated through experimental results. Using the optimal parameter set, the surface roughness (Ra) was reduced from 900 nm to 85 nm. The energy resolution of the polished CLYC: 0.5% Ce crystal reached 5.73%, meeting the requirements for practical applications.
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STC M |
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Finding hidden spindle bearing defect periods using Ramanujan filter banks
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Mohit Law (2)
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STC M, 74/1/2025, P.477
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Keywords: Spindle, Monitoring, Defect |
Abstract : Classifying defects is difficult when spindle bearings have multiple faults that interact with each other and result in the measured vibrations exhibiting cyclo- and non-stationarity. For such cases, this paper shows that the Ramanujan sum when used as a basis to construct filter banks helps decompose the signal into its individual components that makes it possible to estimate hidden defect periods. Illustrative examples with different spindle types show how filter banks can identify periods not obvious in the signal’s Fourier spectra, or in spectrograms, or even those left unclassified by the envelope spectrum method or the empirical mode decomposition method.
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Automatic preload adjustment for ball screw drives by means of a spring-loaded mechanism
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Alexander W. Verl (2), Oliver Jud
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STC M, 74/1/2025, P.483
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Keywords: Machine tool, Ball screw, Preload adjustment |
Abstract : Preloaded ball screw drives are widely used in high-precision linear motion applications, particularly in machine tool feed drives. To compensate for the loss of preload due to wear over the service life and to maintain typical operational characteristics such as zero backlash and high rigidity, ball screws are usually preloaded to high values. However, this results in increased wear and friction, with a consequent increase in temperature. To address these issues, this paper introduces a novel double nut design for ball screws, featuring a passive preload adjustment mechanism, enabling reduced preload levels while enhancing operating characteristics and operational service life.
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Automated identification of joints dynamic parameters in moving industrial robots for milling applications
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Jihyun Lee, Ali Khishtan / Simon S. Park (1)
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STC M, 74/1/2025, P.487
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Keywords: Robot, Machining, Identification |
Abstract : Industrial robots are increasingly used in machining due to their high degrees of freedom and large working space, however, their low structural rigidity limits machining precision. Accurate dynamic models are essential for improving machining performance. This study introduces a novel fast-chirp centrifugal force excitation approach for joints dynamic parameter identification during robot motion. The method effectively captures the in-motion joint’s frictional behavior and accommodates changes in robot configurations along the tool path. Experimental results demonstrate that the dynamic model, integrated with the proposed identification method, accurately predicts chatter stability in robotic milling operations.
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Thermal displacement reduction based on heat transfer characteristics under environmental temperature changes
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Koji Ota, Daisuke Kono (2), Masahiko Mori (1)
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STC M, 74/1/2025, P.493
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Keywords: Thermal error, Machine tool, Thermal deformation |
Abstract : This paper proposes a machine tool design methodology that balances the heat capacity of the machine structure with heat inflow, ensuring a uniform temperature distribution and reducing thermal displacement caused by environmental temperature changes. Heat inflow at each part of the structure is quantitatively determined based on the heat capacity distribution. The target structure is systematically selected through thermal sensitivity evaluation. This methodology was applied to a turning center, and experimental results demonstrated that a uniform temperature distribution was achieved, reducing thermal displacement.
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Material hybrid and sensor integrated lightweight machine tool components
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Hans-Christian Moehring (2), Michelle Engert, Kim Torben Werkle
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STC M, 74/1/2025, P.499
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Keywords: Machine Tool, Material, Integration |
Abstract : Lightweight machine tool components provide the potential of improved system dynamics and reduced energy consumption. In this research, pre-stressed fiber-reinforced polymer concrete (PFRPC) structures were investigated, focusing on lightweight design and functional integration. An integrated strain measurement functionality was realized by embedding Fiber Bragg Gratings (FBG). Two versions of machine tool cantilever arms in the form of a Stewart platform were built using remaining plastic molds. The mechanical properties and operational characteristics were analyzed and compared with those of a conventional steel structure showing the high potential of the hybrid material with regard to the improved system dynamics.
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AI-based sensor layout for predicting thermal deformations of CFRP machine tools
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Felix Finkeldey, Makoto Kato, Petra Wiederkehr (2), Yasuhiro Kakinuma (2)
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STC M, 74/1/2025, P.505
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Keywords: Thermal error, Machine, AI-based sensor layout |
Abstract : Using data-based approaches, accurate predictions of thermal deformations, which can significantly affect the quality of manufactured components, can be enabled. However, a sufficient amount of data with maximised information content is necessary for efficient training. In this paper, an approach for optimising sensor configurations for predicting thermal deformations is presented. From initially 300 temperature sensors, the number of required sensors was significantly reduced while maintaining predictive accuracy. Furthermore, a pattern for sensor placement was identified, providing the potential for an efficient sensor layout that enables cost-effective data acquisition and improved monitoring of machining and wear progression of machine tool components.
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Large-scale functional patterning using mobile robot swarms and ergodic control
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Malachi Landis, Muye Jia, Annalisa T. Taylor, Todd D. Murphey, Ping Guo (2)
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STC M, 74/1/2025, P.511
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Keywords: Surface modification, robot, ergodic control |
Abstract : Large-scale surfaces, such as ship hulls, face challenges in applying functional structures due to manufacturing constraints. This work presents a scalable approach using low-cost, autonomous robot swarms guided by an ergodic control framework to pattern micro-scale features on meter-scale metallic surfaces. The robots operate collaboratively to achieve density-specific coverage, optimizing surface functionalities like friction reduction and hydrodynamic performance. Experimental validation demonstrates the critical role of feature density in tribological performance, and an example application highlights the creation of gradient-density patterns. This innovative method unlocks new possibilities for functional surface patterning on large-scale structures with imprecise robots.
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Cutting force reconstruction in milling by multi-sensor fusion with hybrid aid of process and data-driven models
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Shuntaro Yamato / T. Moriwaki (1)
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STC M, 74/1/2025, P.517
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Keywords: Monitoring, Digital twin, Cutting force |
Abstract : This paper proposes an approach to cutting force reconstruction in milling combining a machine learning model with cutting process simulations. The machine learning model is developed in the feature space of amplitude spectra associated with the tooth-passing components extracted through the moving Fourier transform of time series data. Subsequently, the cutting force time waveform is reconstructed by integrating the estimated amplitude spectra with phase information provided by a cutting simulator. This approach facilitates efficient model construction compared to directly using time waveforms for training. It also enables straightforward multiple-sensor fusion using the ML model, thereby enhancing estimation performance.
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Compensation of blank warpage in punching processes through an innovative adaptive control system for adjusting part holder forces
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Mathias Liewald (2), Stephan Nießner
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STC M, 74/1/2025, P.523
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Keywords: Punching, Adaptive control, Flatness |
Abstract : Punched sheet metal parts are shear cut at least once during production. Shearing sheets generally cause dislocation movements in the lattice structure, leading to inhomogeneous stress distributions and thus part warpage. Although strategies for avoiding warpage are principally known, flatness tolerances of high-quality punched parts often cannot be met since specific and experience-based adjustments of machine parameters are required. This paper presents a method for automatically compensating for warpage of perforated blanks by adapting part holder forces acting in a innovative punching tool. Cutting force measurements from previous process sequences and a machine learning model are considered for this adaption.
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Entangled chip removal utilizing mass-spring model with mobile manipulator
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Ryuki Takahashi, Hayato Kimura, Yasuhiro Kakinuma (2)
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STC M, 74/1/2025, P.529
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Keywords: Robot, Chip, Automation |
Abstract : This study aims to automate the removal of entangled chips in manufacturing environments using a mobile manipulator. Despite advancements in factory automation technology, this task often necessitates manual intervention. Accordingly, this study proposes a deformable chip model (based on a reconfigurable mass-spring system per frame), incorporating visual chip tracking data and force reactions. Consequently, to evaluate the removal state, an efficient removal strategy is derived by defining the instantaneous stiffness and energy absorption rate. Validation of system performance through two removal tests demonstrates the feasibility of automating entangled chip removal, contributing to enhanced operational efficiency in fully automated production lines.
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Low frequency feed modulation assisted milling for chatter avoidance
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Yutaro Kawana, Seyed Mahmood Shantiaeezade, Burak Sencer (2), Ryosuke Ikeda, Norikazu Suzuki (2)
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STC M, 74/1/2025, P.535
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Keywords: Milling, Chatter, Feed modulation |
Abstract : This paper presents a low-frequency vibration assisted machining strategy to improve dynamic stability of milling operations. Machine tool feed-drives are utilized to introduce low-frequency and low-amplitude feed modulations that are used to control tool’s cutting-edge engagement. The pitch angle of a tool can be altered to effectively realize variable pitch cutting kinematics. Feed modulation signal is automatically adjusted to suppress chatter vibrations on-the-fly. Experimental results show that a conventional 4-flute cutter can be transformed to cut with 3 or less teeth with variable pitch arrangement to improve both the asymptotic chatter stability limit and the lobe structure to maximize productivity.
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A novel electromagnetic end-effector with adaptive force-stiffness coordinated control for robotic grinding with variable workpiece stiffness
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Jixiang Yang, Xu Tang, Han Ding, Yuehong Yin (1)
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STC M, 74/1/2025, P.541
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Keywords: Robotic grinding, stiffness control, force control |
Abstract : This paper presents an adaptive force-stiffness coordinated control framework for self-developed electromagnetic variable stiffness end-effector (EMVSE) used in robotic grinding with varying workpiece stiffness. The EMVSE generates actively controlled stiffness and force through designed voice coil motor and electromagnetic spring. The force-stiffness coordination control combines an optimized nonlinear PID force controller with bounded tracking error constraints and a self-stiffness controller based on real-time workpiece stiffness estimation, thereby achieving precise force control for grinding with variable workpiece stiffness. Experiments validate the effectiveness of the proposed method in improving the force control accuracy, material removal accuracy and surface quality of robotic grinding.
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Increasing milling stability predictions accuracy considering speed dependent spindle behaviour with an automated measurement device
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Omer Ozkirimli, Erdem Ozturk (2)
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STC M, 74/1/2025, P.547
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Keywords: Spindle, Measurement, Chatter |
Abstract : Manufacturers seek to enhance productivity by investing in high-speed machine tools. However, at elevated spindle speeds, dynamic characteristics of spindles may change due to thermal loads on bearings, complicating the task of finding optimal spindle speeds. To address this issue, an automated measurement system was developed to evaluate dynamic characteristics of tooling assemblies under rotating conditions. The system employs a solenoid actuator for excitation and capacitance probes for response measurement. Dynamic measurements and milling tests were conducted on a 5-axis milling machine tool and benefits of the system in improving accuracy of stability prediction are presented.
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Directional factor as the key factor for chatter free robotic milling of light alloys
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Zoltan Dombovari, Iñaki Laka, Andras Bartfai, Ali Karaca, Erhan Budak (1), Gabor Stepan (1), Jokin Munoa (1)
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STC M, 74/1/2025, P.553
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Keywords: Robot, Milling, Chatter |
Abstract : Robotic milling systems are increasingly used for light alloys and composites, but face challenges due to high dynamic flexibility of robots. A key issue is low-frequency chatter, linked to the robot's structural modes during high-speed operations. Therefore, this study deals with a dominant flexible mode with high tooth-passing frequencies, highlighting the influence of the directional factor. Negative directional factors can cause low-frequency chatter at high spindle speeds. Polar stability lobes show that optimal feed direction and radial engagement zones align with positive directional factors. The study shows that slotting operations assure a chatter free machining. Experimental validation confirms theoretical findings..
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Cascaded FIR and half-sine filter-based smooth trajectory generation algorithm
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Yusuf Altintas (1), Mobin Abdar Esfahani, Behnam Karimi, Owen Gatenby
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STC M, 74/1/2025, P.559
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Keywords: CNC, Motion, Trajectory |
Abstract : It is desired to deliver smooth time-stamped position commands to the feed drives of the multi-axis CNC machine tools. This paper presents a new trajectory generation algorithm that consists of a cascaded Finite Impulse Response (FIR) and a half-sine filter. FIR filter is used to set the acceleration, and the half-sine wave generates continuous velocity-acceleration and jerk motions along the tool path while avoiding the excitation of the machine vibrations. By adjusting the overlap time of axis commands, the algorithm allows for control of cornering errors between the discontinuous path segments similar to FIR filters. The algorithm is experimentally validated on a two-axis machine and a tool path with sharp curvatures.
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Tool path generation for precision roughing of blisks via abrasive waterjet machining
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Lutfi Taner Tunc (2)
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STC M, 74/1/2025, P.563
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Keywords: Waterjet machining, Nickel alloy, Tool path. |
Abstract : Manufacturing process chains of bladed disks are energy intense. Heat resistant properties of Inconel alloys make them very challenging to cut by conventional milling at roughing conditions, where excessive cutting forces and vibration arise. Abrasive waterjet machining (AWJM) offers several benefits in cutting of such materials. In the literature, 5-axis AWJM of blisks is not well studied for machining strategy, parameter selection and tool path generation. This paper presents a unified approach for development of 5-axis AWJM roughing of blisks. The proposed approach is demonstrated on a representative part made of Inconel 718.
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Feedrate optimization based on part-to-part learning in repeated machining
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Cheng-Hao Chou, Chenhui Shao, Chinedum E. Okwudire (2)
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STC M, 74/1/2025, P.569
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Keywords: Computer numerical control (CNC), machine learning, feedrate optimization |
Abstract : Cutting operations often involve machining parts of similar geometry repeatedly, offering opportunities for learning-based improvements. While past studies have focused on enhancing machining accuracy through part-to-part learning, this work shifts the focus to optimizing feedrate under servo error constraints. A data-driven model, trained online on prior machining data, predicts future servo errors and enables iterative feedrate optimization. Confidence in the model improves as more parts are machined, permitting progressively higher feedrates. Experimental results demonstrate significant speed gains within a few iterations, showcasing the potential of part-to-part learning for autonomously achieving faster machining without violating servo error constraints.
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Interaction between forced and chatter vibrations through flank-workpiece interference
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Takehiro Hayasaka (2), Hayato Murai, Kyungki Lee, Eiji Shamoto (1)
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STC M, 74/1/2025, P.575
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Keywords: Chatter, Damping, Forced vibration |
Abstract : In this paper, the interaction between forced and chatter vibrations through flank-workpiece interference is studied. The effect of the well-known process damping, which occurs due to the contact between the flank face and the workpiece, on the chatter stability has been studied broadly. However, this contact should occur by forced vibration also, which has not been studied much in the literature. Due to this contact, forced vibration should suppress chatter, and vice versa, interaction should occur. A model is constructed to evaluate this interaction, and the interactive effects are clarified through simulations and experiments.
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Overcoming sparse run-to-failure data dhallenges in manufacturing: A contrastive mixer framework for remaining useful life prediction
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Eunseob Kim, Hojun Lee, Yuseop Sim, Jiho Lee, Martin B.G. Jun / F. E. Pfefferkorn (1)
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STC M, 74/1/2025, P.579
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Keywords: Monitoring, Machine Learning, Plasma |
Abstract : Remaining useful life (RUL) is a crucial indicator in industrial settings to enhance manufacturing efficiency, but its precise and cost-effective prediction remains challenging, especially with deep learning (DL) methods requiring large, well-curated datasets. To address this, we propose the Contrastive Mixer (CM) framework, which leverages partially labeled small run-to-failure datasets to deliver high-performance RUL prediction. Implemented on a plasma arc cutting (PAC) tool to monitor plasma nozzles, the CM framework significantly outperforms existing DL methods. Given its adaptability and efficiency make it a promising solution for accurate RUL prediction across diverse manufacturing applications.
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STC O |
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Adaptive production control for agile disassembly systems in remanufacturing
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Marco Wurster, Fabian Erlenbusch, Finn Bail, Gisela Lanza (1), Nicole Stricker
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STC O, 74/1/2025, P.585
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Keywords: Adaptive control, Remanufacturing, Disassembly |
Abstract : Uncertainties in disassembly lead to low efficiency and high disassembly costs, prohibiting remanufacturing for economic reasons. While agile hybrid disassembly systems (AHDS) could provide a capable platform, they require a sophisticated production planning and control (PPC). This work presents a dynamic production planning and control approach for disassembly (D-PPC) for AHDS, consisting of a reactive control with CONWIP order release and an automated logically adapting Multi-Priority Rule order allocation. Results show that the approach can handle disruptions due to process failure and leads to improved throughput and lower costs, especially reducing delay costs.
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Optimal control of remanufacturing systems with uncertainty in quality identification
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Maria Chiara Magnanini, Tullio Tolio (1)
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STC O, 74/1/2025, P.591
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Keywords: Remanufacturing systems, control, stochastic modelling, electric motors |
Abstract : Uncertainty about quantity and quality of returned end-of-use products represents a relevant aspect in the design and operation of remanufacturing systems. This paper proposes a novel optimal control policy to maximize the expected margin of a motor OEM remanufacturing electric motors. The control policy targets multiple quality classes of returning cores, and it accounts for imperfect inspection as well as for finite production capacity of the remanufacturing system. The optimal policy allows to estimate the impact of variability of quality and quantity of cores on the resulting flow of remanufactured products which is fundamental to design the remanufacturing supply chain.
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Predictive maintenance optimization for manufacturing systems considering perfect and imperfect inspections: application to injection molding machine
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Duc-Hanh Dinh, Phuc Do, Benoit Iung (1), Tao Quang Bang
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STC O, 74/1/2025, P.597
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Keywords: Predictive Maintenance, Inspection, Optimization |
Abstract : Predictive Maintenance is a promising strategy for anticipating failures of manufacturing systems through degradation control. While inspections assess health and guide maintenance decisions, their costs pose challenges. To minimize inspection costs, this paper proposes an adaptive non-periodic inspection model combining cost-effective (but less reliable) imperfect inspections with accurate (yet costly) perfect ones. The originality of this approach lies in its ability to dynamically optimize inspection types and intervals based on system lifetime prognosis. The model is validated through a case study of an injection molding machine, demonstrating superior performances compared to conventional inspection models.
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Bridging planning silos: A cross-functional decision support system for capacity, order, and supplier decisions in global production networks
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Martin Benfer, Moritz Hörger / H. Weule (1)
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STC O, 74/1/2025, P.603
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Keywords: Manufacturing network, Production planning, Optimisation |
Abstract : The complexity and dynamism of global production networks require interlocked decision-making processes, including planning production capacity and capabilities, allocating orders, and selecting supplier options. In large companies, these planning processes are spread over several functions, leading to inefficient global decisions and increased coordination costs. This work proposes an integrated planning process for multi-echelon production networks that includes all three decision types mentioned. A systematic design process is developed and implemented as an optimisation problem. The results from an automotive supplier use case demonstrate significant advantages over the existing fragmented planning approach, as well as improvements in decision-making time.
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Joint optimization of logistics operations and reliability-based replacement policies in a geographically distributed service parts logistic system
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Po-Han Wang, Dragan Djurdjanovic (2)
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STC O, 74/1/2025, P.609
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Keywords: Logistics, Reliability, Joint logistic and maintenance optimization |
Abstract : A joint location-inventory-maintenance model is proposed for a geographically distributed Service Parts Logistics problem. The model uses a reliability-based replacement strategy and is formulated as a quadratic Mixed Integer Linear Program which jointly optimizes logistic and preventive part replacement decisions. The proposed solution method employs piecewise linearization to provide a level of tractability and scalability to the method. The newly proposed joint location-inventory-maintenance model is evaluated and benchmarked against traditional local optimum-based replacement approaches. It consistently outperformed the benchmark models, with the efficiency of cost effect improvements determined by the relative prevalence of logistics factors versus asset management costs.
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Simultaneous design of reconfigurable manufacturing systems and their production plans using hierarchical reinforcement learning
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Soham S. Purohit, Anirudh Kanchi, Haochen Wu, Bogdan I. Epureanu (2)
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STC O, 74/1/2025, P.615
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Keywords: Reconfigurable manufacturing systems, artificial intelligence, multi-agent systems, autonomous manufacturing systems |
Abstract : Reconfigurable manufacturing systems (RMSs) composed of modular machines are able to autonomously collaborate and adapt to fluctuating demands and address challenges such as mass personalization. To that aim, RMSs require an optimal design of the ensemble of machines in the system, namely the optimal selection of modules each machine should have. This design is difficult because RMS performance metrics require optimal production planning, which depends in complex ways on the RMS design. This paper proposes an approach using hierarchical reinforcement learning that simultaneously designs the machines in an optimal RMS and determines the optimal production plan. The integrative and explorative capabilities of the proposed method determine the best-performing RMS design even under complex constraints, while the production plan optimally responds to fluctuating demands. Results demonstrate high computational efficiency and robustness of solutions that also scale with the RMS size and complexity.
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A Large Manufacturing Decision Model for Human-Centric Decision-Making
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Xingyu Li, Aydin Nassehi (1), S. Jack Hu (1), Byung Gun Joung, Robert X. Gao (1)
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STC O, 74/1/2025, P.621
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Keywords: Manufacturing system, Generative artificial intelligence, Digital twin |
Abstract : To adapt to changing demands and disruptions, manufacturing systems necessitate dynamic reconfiguration, facilitated by growing digitalization, modularity, and autonomy. Such reconfiguration, however, heightens decision-making complexity and the need for human supervision. While Generative AI (GenAI), particularly large language models (LLMs), fosters natural human-resource interactions, existing methods lack manufacturing-specific context. This paper introduces a Large Manufacturing Decision Model (LMDM) leveraging image generative models to precisely represent and generate manufacturing-specific reconfiguration decisions using a digital twin, minimizing data requirements and reducing hallucination risks. Simulation results showcase LMDM’s ability to refine system configurations through human guidance, transforming digital twins into human-centric decision-making tools.
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Factory layout planning using Quantum Annealing
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Xiangqian Wu, Philipp Schworm, Matthias Klar, Jan C. Aurich (1)
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STC O, 74/1/2025, P.627
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Keywords: Factory, Planning, Quantum Computing |
Abstract : Factory layout planning is a central task in manufacturing system design, affecting transportation routes, throughput times, and resource utilization. While manual methods and traditional approximative approaches often fall short of industrial demands due to time and quality constraints, quantum annealing presents a promising alternative. This paper introduces a constrained quadratic model for automated factory layout planning, incorporating multi-criteria objectives and scalability. Utilizing data from an industrial scenario, the approach is benchmarked against non-dominated sorting genetic algorithm II for greenfield and brownfield planning. The results demonstrate quantum annealing’s superior performance in solution quality through reductions in transport intensity and space optimization.
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Economic valuation of flexibility in production capacity using real options valuation
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Günther Schuh (1), Seth Schmitz, Calvin Kuhn, Tobias Simon
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STC O, 74/1/2025, P.633
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Keywords: Production planning, Uncertainty, Flexibility |
Abstract : Uncertain prognoses lead to increasing challenges in right-sizing production capacity. Flexibility in production capacity addresses uncertain prognoses by enabling adjustments to meet customer demand. The economic implementation of flexible capacity requires economic quantification given multiple uncertainties and multiple flexibility measures. Existing methodologies for this quantification consider only singular sources for uncertainty or flexibility, resulting in the overvaluation of production capacity and undervaluation of flexibility. This paper presents a novel approach for the valuation of production capacity, in which multiple sources for uncertainty and flexibility can be considered. The approach was validated in a real investment in production capacity from industry.
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Integrating digital factory twin and AI for monitoring manufacturing systems through synthetic data generation and vision transformers
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Marcello Urgo (2), Walter Terkaj
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STC O, 74/1/2025, P.639
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Keywords: manufacturing, digital twin, artificial intelligence |
Abstract : Integrating Digital Twin and Artificial Intelligence technologies is reshaping manufacturing monitoring systems by leveraging synthetic data and advanced computer vision models. This paper presents an approach where a Digital Twin of a factory is used to generate synthetic datasets to train Vision Transformers for object detection and image segmentation in manufacturing processes. The study demonstrates improved accuracy in detecting and monitoring factory assets, validated through synthetic and real-world datasets. An industrial case study further illustrates its potential to identify anomalies.
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Multidimensional perceived quality: Extended level model and case study including sustainability as a quality dimension in the perception of plastic packaging
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Jan A. Körkemeyer, Hanna Brings, Benjamin Montavon, Robert H. Schmitt (1)
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STC O, 74/1/2025, P.645
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Keywords: Quality, Product development, Perceived quality |
Abstract : Perceived quality describes a customer’s subjective quality assessment of a product. State-of-the-art methods relating this assessment to objective criteria and subsequently measurable technical parameters use a single dimension of overall quality perception. However, quality dimensions are continuously evolving with new customer expectations such as sustainability or usability. Therefore, an extended level model for quality perception incorporating multiple dimensions and analyzing dominance of senses is proposed. It is applied in a descriptive perception study for plastic packaging encompassing sustainability and traditional quality dimensions. Surface roughness, gloss, and color lightness are identified as relevant to the subjective evaluation dominated by optical sensation.
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Advancing quality prediction in polymer PBF-LB: a hybrid AI and physics-guided approach
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Matteo Calaon, Hao-Ping Yeh, Shuo Shan, Yang Zhang,(2), Jesper Henri Hattel, Hans Nørgaard Hansen (1)
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STC O, 74/1/2025, P.651
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Keywords: Additive Manufacturing, Virtual Inspection, Physics-guided AI |
Abstract : The future of advanced manufacturing relies extensively on process information, multiphysics modelling and systems networking. This study explores a novel approach to part quality prediction combining in-process sensor data from three identical systems, physics-guided model and offline CT measurement. The laser powder bed fusion (PBF-LB) process for polymers served as case technology platform for this study. Data from physics-guided model were utilized to train an AI model capable, after training, to confidently predicts the dimensions of printed artifacts. This work drives a paradigm shift in industrial decision-making, reducing reliance on costly, time-intensive domain-specific expertise.
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STC P |
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Measurement of spindle-related geometric errors by multilateration
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Kotaro Mori (2), Masahiro Shimoike, Keito Abe
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STC P, 74/1/2025, P.657
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Keywords: Machine tool, Measurement, Kinematic Error |
Abstract : The orientation of the tool must be considered to ensure machining accuracy. It usually coincides with spindle orientation. Combining a test mandrel and a dial gauge is still the most popular method to measure spindle-related geometric errors. Simultaneous measurement of the volumetric errors of the feed axis and the parallelisms between a spindle and a feed axis has not been experimentally studied. This study demonstrates a simultaneous measurement of these errors by utilizing multilateration. Quaternions are utilized in kinematic modelling for efficient computation. Validation experiments are conducted at a machining center. A variance-covariance matrix is utilized to evaluate measurement uncertainties.
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Traceability and uncertainty of defects automated measurements by CNN-powered Machine Vision Systems
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Giacomo Maculotti, Lorenzo Giorio, Gianfranco Genta, Maurizio Galetto (2)
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STC P, 74/1/2025, P.661
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Keywords: Visual Inspection, Uncertainty, Convolutional Neural Network (CNN) |
Abstract : Surface geometric imperfections can be automatically inspected by machine vision systems. State-of-the-art applications prefer resorting to image analysis by Convolutional Neural Networks (CNNs), rather than traditional traceable inspection methods. CNNs have the advantage of greater speed, flexibility and automation but lack traceability, thus hindering quantitative quality controls and tolerances verification. This work proposes a methodology to estimate the uncertainty of automated measurements of surface geometrical imperfections based on CNNs while establishing traceability by leveraging on a photogrammetric system. The methodology is demonstrated on a gas metal arc welding of aluminium alloys for inspecting and measuring the quality of surface pores.
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Transferability of compliance error compensation parameters in articulated robots
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Monica Katherine Gonzalez, Theodoros Laspas, Hung-Ching Lin, Kanako Harada, Andreas Archenti (2)
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STC P, 74/1/2025, P.667
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Keywords: Calibration, Robot, Compliance |
Abstract : While robot calibration is crucial for performing high-precision tasks, traditional calibration methods are time-consuming and resource-intensive. Within the constraints of industrial settings, extensive calibration requirements call for alternative methods that minimize the implementation costs while maintaining acceptable accuracy levels. This paper investigates the feasibility of transferring compliance error compensation parameters among articulated robots of the same model in contact-based applications. Experimental results demonstrate the feasibility of the transferability, achieving significant error reduction with a modest performance decrease compared to individual robot calibration. This approach offers a promising avenue for balancing calibration effort with the specific application requirements.
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Comparison of measuring methods for the dimension-over-balls parameter MdK using modified gear standards
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Anke Guenther (2), Gert Goch (1)
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STC P, 74/1/2025, P.673
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Keywords: Gear, Metrology, Dimension over balls |
Abstract : Gears are subject of increasing accuracy requirements. The measuring processes are usually traced back to calibrated gear standards. Differences between the calibration process and serial inspections led to enhanced measurement uncertainty, especially for gear standards with intentionally modified flanks. This article analyses the dimension-over-balls parameter (MdK) on cylindrical gear standards with modifications. MdK-values, calculated from measured pitch points, show significant deviations from calibration values. A mathematical solution is presented that interprets flank angle modifications as changes of the standard’s basic geometry. Experiments showed that this approach offers improved MdK–evaluations, even if the pitch probing points differ from the contact points of MdK–probing balls.
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Frequency-comb-referenced Terahertz Fabry-Pérot interferometry for monitoring semiconductor wafer thinning process with a nanometer precision
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Guseon Kang, Jaeyoon Kim, Jun Hyung Park, Sukkyung Kang, Dong Geun Kim, Young-Jin Kim (2)
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STC P, 74/1/2025, P.679
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Keywords: Ultra-precision, Semiconductor, Polishing |
Abstract : High-precision, non-destructive thickness measurement is essential in semiconductor manufacturing. Optical methods often struggle with strong surface scattering and absorption during wafer thinning. We present nanometer-precision, non-destructive wafer thickness measurement using the absolute frequency positions of Fabry-Pérot interference modes in the terahertz frequency regime, referenced to a frequency comb. By leveraging the comb’s SI-traceable frequency uncertainty and terahertz radiation’s scattering insensitivity, this approach achieves a 58.4-nm precision in 0.2-s and 7.2-nm in 25.6-s averaging. Such unprecedented performance enables effective monitoring of wafer thinning processes (e.g., chemical mechanical polishing), crucial for advanced semiconductor packaging.
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Multiscale optical surface integrating multifocal imaging and wavelength filtering for compact snapshot spectral imaging
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Xinquan Zhang (2), Yaoke Wang, Hao Wu, Limin Zhu, Ping Guo (2)
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STC P, 74/1/2025, P.685
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Keywords: Optical, ultra-precision, spectral imaging |
Abstract : Snapshot spectral imaging enables single-exposure acquisition of spectral images but is constrained by bulky designs and compromised spatial resolutions. This study presents a multiscale optical surface that integrates macro-scale structures for multifocal imaging and micro-scale staircases for wavelength filtering into a unified ultra-compact form. The design employs a multiscale framework grounded in Fourier optics and is fabricated using ultra-precision diamond turning. Validation experiments demonstrate the system's ability to capture discrete spectral images using only a single optical component, with measured spectral characteristics closely matching theoretical predictions. This new design provides a compact and cost-effective solution for diverse spectral imaging applications.
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A non-Michelson type three-axis grating interferometer using linear scale gratings
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Ryo Sato, Yifan Hong, Hiraku Matsukuma, Wei Gao (1)
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STC P, 74/1/2025, P.691
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Keywords: Metrology, Interferometry, Displacement |
Abstract : A non-Michelson type grating interferometer with multiple measurement beams is proposed to make three-axis displacement measurements using a combination of four linear scale gratings instead of a planar grating scale. The configuration of the optical system and the measurement principle are described. A theoretical uncertainty evaluation is conducted to evaluate the influence of the grating installation errors. The result indicates that when the angular installation error of the gratings is less than 0.1°, the corresponding measurement uncertainty is on the order of 10 nm within a 10 mm measurement range. Finally, the feasibility of three-axis displacement measurement is demonstrated experimentally.
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Three-dimensional measurement of structures with smooth-steep-surfaces using autofluorescence confocal signal
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Masaki Michihata, Motoya Yoshikawa, Shuzo Masui, Satoru Takahashi (1)
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STC P, 74/1/2025, P.697
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Keywords: Probe, Structure, Fluorescence |
Abstract : Autofluorescence-based three-dimensional measurement technique was developed. Structures with smooth and steep surfaces are difficult to measure with conventional measurement methods. In this study, we propose a new optical three-dimensional measurement method that uses fluorescence emitted by the object itself as a response signal. A theoretical model was proposed and validated for surface detection, and the model was in good agreement with experimental data and highly consistent with confocal microscopy results. Using the proposed method, we successfully measured a Blu-ray disc pick-up lens. The results demonstrated that the method could accurately measure steep slopes of up to 76° and vertical surfaces. These findings confirm the capability of the proposed method to measure structures with both smooth and steep surfaces effectively.
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Spectral imaging for 2-D wavelength mapping by chromatic phase retardation
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Ki-Nam Joo, Seongwook Jang / S.-W. Kim (1)
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STC P, 74/1/2025, P.703
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Keywords: Optical, Metrology, 2-D wavelength mapping |
Abstract : We present a single snap-shot method of spectral mapping of a target surface by sampling its chromatic phase retardation through a birefringence waveplate. The planar field of polarization-dependent phase retardation is produced in response to the spectral distribution of the target surface, which is instantaneously segmented and captured using a polarization-array digital camera. This method permits 2-D wavelength mapping with a spectral resolution of 0.4 nm, being well suited for thin-film profile measurements with a 1 nm thickness repeatability. The method can also be used for other scientific and engineering applications demanding fast and precise spectral sampling.
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Local heat transfer detection via passive dual probe near-field microscopy
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Yusuke Kajihara (2), Ryoko Sakuma, Yoshiki Nagai, Kuan-Ting Lin
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STC P, 74/1/2025, P.707
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Keywords: Surface analysis, Temperature, Nano technology |
Abstract : This paper describes the experimental demonstration of nondestructive local heat transfer detection with a passive dual probe near-field microscope. The passive dual probe near-field microscope consists mainly of an atomic force microscope with two probes, a confocal optical system, and a sensitive infrared detector with detection wavelength of 14.5 µm. Relationships between probe height and near-field signals confirmed that the passive dual probe near-field microscope could achieve simultaneous detection of thermally excited evanescent waves from two different points with sub-micrometer distance. After the calibration from near-field signal intensity to actual surface temperature, we finally achieved the local heat transfer between two points on the Ti heated sample with the developed microscope. This experimental validation greatly advances the realization of nanoscale heat transfer measurements for semiconductor devices with very fine patterns.
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Investigation of the correlation between radiographic image quality and surface measurement quality of XCT using frequency response analysis
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Xiao Chen, Shan Lou, Wenjuan Sun, Paul Scott, Xiangqian Jiang (1)
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STC P, 74/1/2025, P.713
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Keywords: X-ray computed tomography, Metrology, Quality control |
Abstract : X-ray computed tomography (XCT) is developing into a dimensional metrology tool. However, its quality control remains challenging due to the unknown correlation between radiographic image quality and surface measurement quality. This paper investigates this correlation by comparing the modulation transfer function (MTF) of radiographic image with the surface amplitude transfer function (SATF). Results indicate that the limit of measurable surface scale can be predicted by MTF10%. While the shape of the filtering effect on XCT measured surface can be predicted from MTF, the measurement error from this effect cannot be predicted due to the influence of surface determination.
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Investigating the effects of machine learning generalisation for enhancing accuracy in fast X-ray computed tomography for industrial metrology
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Filippo Zanini, Nicolò Bonato, Diego Pentucci, Simone Carmignato (1)
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STC P, 74/1/2025, P.719
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Keywords: Metrology, X-ray computed tomography, Machine learning |
Abstract : Industrial X-ray computed tomography enables comprehensive inspections, but the measurement accuracy can be compromised at high scanning speeds due to reduced image quality. Machine learning shows promise in enhancing tomographic reconstructions under challenging conditions, yet its generalisation across varying factors is crucial for maintaining accuracy. This research proposes an experimental methodology to investigate the sensitivity of various scanning conditions to the degree of machine learning generalisation and evaluates the accuracy improvements achievable with increasing generalisation. Findings lay the foundations for efficiently integrating machine learning into fast tomography workflows to bridge the accuracy-speed gap for industrial metrology applications.
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X-oscillation-coordinated fly-cutting of highly uniform microlens arrays
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Zhiwei Zhu, Tianxiao Chang, Rongjing Zhou, Peng Huang / W.S. Lau (1)
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STC P, 74/1/2025, P.725
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Keywords: Ultraprecision, Fly-cutting, Optical, Microstructure |
Abstract : We report an X-oscillation-coordinated fly-cutting (XOFC) technique for generating ultra-precision microlens arrays (MLAs). In the XOFC, the X-axial oscillation was employed to coordinate with the rotated diamond tool to individually form the lenslet with desired shapes in each revolution of the spindle. Compared with diamond turning, the high process repeatability, continuous motions, one-step shaping without enveloping multiple tool motions, and less error resources enable the XOFC to generate MLAs with high uniformity, high surface quality, and high efficiency. As a demonstration, 10,000 sphere MLAs were generated with form error and surface roughness varied within 1 nm in different regions.
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Ultra precision analytical toolpath calculation for aspherical mirror surface machining
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Eloïse Jeanroy, Julien Chaves-Jacob, Jean-Marc Linares (1), Santiago Arroyave-Tobon, Stephan Imperiali
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STC P, 74/1/2025, P.731
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Keywords: Computer aided manufacturing (CAM),Tool path, Ultra precision |
Abstract : Ultra-precise machining of aspherical mirrors requires high surface quality with form defects below 10 µm. This study assessed the performance of toolpaths generated by commercial CAD/CAM software, focusing on the distance between consecutive toolpath points, variations in these distances, and geometric accuracy. The evaluation showed that commercial tools hinder high-precision toolpath generation due to surface faceting, even with minimized chord error. To mitigate this, a new analytical toolpath calculation method was proposed. Two Zerodur® mirrors were machined with programs coming from this method and commercial CAM software. These tests highlight a reduction of 52.8% in form defect with our solution.
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In-process reconstruction of 3D surface profile for ultra-precision cutting of microstructured surfaces from cutting force monitoring and compensation
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Liang An, Yuan-Liu Chen (2), Zhongwei Li, Genshen Liu
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STC P, 74/1/2025, P.737
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Keywords: In-process measurement, Surface, Ultra-precision cutting |
Abstract : In-process surface metrology for ultra-precision cutting is challenging since the influences from the cutting fluid and the cutting chips. Although cutting force measurement can be in-process carried out for monitoring of cutting status such as tool wear or chatter, it cannot be applied for quantitative in-process surface metrology due to insufficient sensitivity and stability. This paper presents an in-process 3D surface profile reconstruction method for ultra-precision cutting of microstructured surfaces. A force-sensing tool holder was established, an error compensation algorithm and a force-3D profile evolution model were developed for enabling 3D surface profile reconstruction with nano-precision during ultra-precision cutting processes.
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STC S |
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Modulated-ellipse servo cutting of micro-structured surfaces with high-steep slopes
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Zhanwen Sun, Suet To (2), Waisze Yip, Sujuan Wang, Shanshan Chen, Guanlong Chen
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STC S, 74/1/2025, P.743
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Keywords: Diamond cutting, Micro-structured surfaces, Ultra-precision machining |
Abstract : This study introduces modulated-ellipse servo cutting technology for machining of micro-structured surfaces with high-steep slopes and hybrid micro-structures. MESC is able to jointly control tool orientation and cutting trajectory by integrating multi-axis fast and slow servo motions to create a primary elliptical cutting trajectory with a fixed rake angle. Simultaneously, the elliptical cutting trajectory is modulated by a dual-axial fast servo motion platform to produce desired hybrid micro-structures with information storage. Micro-structural arrays with steep slopes of up to 70° and micro-pits with hybrid micro-structures encoding Morse code information are machined with ultra-fine form accuracy of 30 nm.
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Aliased beating helix induced by dual-frequency vibrations in turning
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Monica Gil-Inchaurza, Xavier Beudaert (2), Maria Garcia, Jose Antonio Sanchez, Jokin Munoa (1)
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STC S, 74/1/2025, P.749
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Keywords: Vibration, Topography, Turning |
Abstract : Machine-tool forced vibrations can generate undesired periodic patterns on the workpiece surface. These helix patterns imply poor surface quality but are valuable for identifying the machine-tool frequencies at fault as well. Thus, mathematical relations between the helix spatial features and the tool vibration frequency are fundamental for the diagnosis. This study investigates the interaction of two distinct vibration frequencies in turning and their influence on the surface. The beating phenomenon and the stroboscopic sampling of the rotary workpiece are applied to derive the aliased beating helix features. The proposed mathematical relations are numerically and experimentally validated in cylindrical turning tests.
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On-machine laser polishing of diamond turned metal surfaces
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XinQuan Zhang (2), JinChi Wu, WenBin Zhong, WenHan Zeng, Zhe Zhang, MingJun Ren
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STC S, 74/1/2025, P.755
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Keywords: Ultra precision, Laser, Polishing |
Abstract : An on-machine laser polishing system is developed to suppress the periodic turning marks on diamond turned metal surface. By integrating laser polishing on an ultra-precision machine tool, this method enables high-efficiency non-contact polishing without taking off workpiece from the lathe. Molecular dynamics simulation and experimental validation prove the process’ capability to reduce surface roughness through atomic level material flow from peak to valley. Surface quality has been improved through effective suppression of the diffraction and rainbow effects after laser polishing, demonstrating a high-efficiency, low-cost and clean solution for high-end optical component manufacturing.
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Investigation of hydrogen embrittlement prevention effect on electropolished 316L austenitic stainless steel
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Sun-Ho Chang, Jun-Young Kim, Hyun-Taek Lee, Eun-Sang Lee / S.-H. Ahn (1)
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STC S, 74/1/2025, P.759
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Keywords: Electro chemical machining, Surface Modification, Hydrogen embrittlement |
Abstract : This study investigated the surface properties of 316L austenitic stainless steel in a hydrogen environment before and after electropolishing. The impact of electropolishing on hydrogen embrittlement resistance was evaluated, and hydrogen desorption in the material was analyzed based on surface conditions. Results demonstrated that changes in chromium content on the electropolished surface affected hydrogen embrittlement susceptibility, confirming the suitability of this treatment for material improvement in hydrogen environments.
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The role of PEEK viscoelasticity in chip formation, surface finish and geometrical accuracy
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Rachele Bertolini, Anna Bottin, Caterina Zanella, Stefania Bruschi (1), Andrea Ghiotti (1), Enrico Savio (1)
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STC S, 74/1/2025, P.765
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Keywords: Cryogenic machining, Surface analysis, Viscoelasticity |
Abstract : Polyether ketone (PEEK) is a thermoplastic polymer increasingly utilized in the biomedical field, where typically low production volumes make machining a cost-effective manufacturing method. Although the viscoelastic nature of polymers is widely acknowledged, this factor is often overlooked when designing cutting processes. In this context, the paper explores how the viscoelastic properties of PEEK affect its machining performance, specifically in terms of chip morphology, surface finish, and geometrical accuracy. Turning trials were conducted under dry and cryogenic cooling conditions, at various cutting speeds, alongside dynamic mechanical thermal analysis at different temperatures and deformation rates. The results demonstrated that, even if PEEK was machined in a glassy state, chip fragmentation was only possible if viscoelasticity was suppressed. Furthermore, achieving a good surface finish depended on the combined effects of temperature and deformation rate. The study also revealed that the enhanced stiffness of PEEK under cryogenic cooling contributed to improved geometrical accuracy when machining the inner surface of biomedical acetabular cup inserts.
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Fabrication of cell orientation control surface on Co–Cr alloy by polycrystalline diamond micromilling
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Kazutoshi Katahira (2), Shinya Morita, Chikahiro Imashiro, Atsushi Ezura, Jun Komotori
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STC S, 74/1/2025, P.771
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Keywords: End milling, diamond tool, cell orientation |
Abstract : This study presents a novel approach to surface texturing on metal cell culture vessels using polycrystalline diamond micromilling. Continuous microgrooves on Co–Cr alloy surfaces were successfully generated by utilizing an ultrafine ball end mill with a tool tip radius of 25 µm. The resulting microgrooves, 30 µm wide, exhibited a surface roughness (Ra) of less than 20 nm. The continuous plastic flow is the primary mechanism driving material removal during the micromilling process with the tool. Additionally, cell culture experiments demonstrated a pronounced alignment of cells in the grooves, especially those created with the 25 µm tool tip radius.
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Liquid-phase plasma machining with floating discharge tool
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Wule Zhu (2), Fang Han, Jingyuan Wang, Weijian Zhang, Wei Gao, Cao-Yang Xue, Bing-Feng Ju
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STC S, 74/1/2025, P.777
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Keywords: Process control, Liquid-phase plasma, ACSM |
Abstract : The demand for third-generation semiconductors such as SiC is increasing, but achieving high-efficiency deterministic material removal with ultra-low surface roughness remains challenging. To address this, a new liquid-phase plasma machining method by utilizing a floating discharge tool was proposed. Analysis and characterization demonstrate the plasma is generated in the hydrodynamic film by the discharge tool, which facilitates the oxidation of SiC surface. Meanwhile, the accompanying photoelectric field catalyses the nano particles to further enhance the material removal significantly. Then, a freeform saddle surface was deterministically fabricated by the new method, achieving sub-nano form control accuracy and surface roughness as well.
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A novel method for high-volume manufacturing of self-protective plastic surfaces to ensure durable anti-counterfeiting functionality
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Marco Sorgato, Giacomo Baruffa, Keltoum Oubellaouch, Giulia Zaniboni, Giovanni Lucchetta (2)
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STC S, 74/1/2025, P.783
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Keywords: Surface modification, Injection molding, Wear |
Abstract : This study presents a novel approach to the high-volume manufacturing of durable self-protective polypropylene surfaces that integrate micro-scale protective grids with sub-micrometer Laser-Induced Periodic Surface Structures. Grids with variable pitches (40–250 μm) were designed to optimize surface durability and nanostructure functionality. Wear tests indicated that smaller grid pitches offered superior protection, significantly prolonging the functional lifespan of the structural color compared to unprotected surfaces. These findings underscore the effectiveness of optimized grid designs in delaying wear progression, providing a scalable and practical solution for durable nanostructured thermoplastic surfaces in industrial applications.
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