THE INTERNATIONAL ACADEMY FOR PRODUCTION ENGINEERING
LOG IN FOR MEMBERS
CIRP ANNALS 2008 |
GO TO STC: A C Dn E F G M O P S Cross-STC |
STC A |
| Assessment of Products for Optimal Lifetime |
| S. Kara (2), S. Manmek, H. Kaebernick (1), S. Ibbotson |
| STC A, 57/1/2008, P.1 |
| Keywords: Sustainable Manufacturing, Environmental Impact, Product Development |
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Abstract : Sustainable manufacturing requires products to be developed with a predetermined useful life, which will minimise resource usage and environmental impact based on their intended End of Life strategy. Long term implementation of this concept requires this objective to be incorporated as another target during the early product development so that each component is designed with an optimum useful life. This paper presents a methodology to assess a product’s life during the design phase based on product failure mechanisms and their associated critical lifetime prediction parameters. A number of products were used to prove the concept and demonstrate the usefulness of the methodology. |
| A Comparison of Manufacturing and Remanufacturing Energy Intensities with Application to Diesel Engine Production |
| J.W. Sutherland (2), D.P. Adler, K.R. Haapala, V. Kumar |
| STC A, 57/1/2008, P.5 |
| Keywords: Environmental, Lifecycle, Remanufacturing |
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Abstract : Climate change reports and policies relating to end-of-use products, CO2 emissions, and energy are
causing manufacturers to examine their operations closely. Several reports have touted the economic and environmental benefits of remanufacturing, including claims of significant reductions in terms of energy and
CO2 emissions. However, large-scale remanufacturing of heavy equipment engine components has not been closely examined and no standard procedure exists to quantify the benefits of remanufacturing. A
methodology is presented for determining the energy intensity and benefits of remanufacturing as compared to new manufacturing, and this is applied to a diesel engine example. These findings are used to estimate the embodied manufacturing/remanufacturing energy across multiple use cycles. |
| Integration of a Service CAD and a Life Cycle Simulator |
| H. Komoto, T. Tomiyama (1) |
| STC A, 57/1/2008, P.9 |
| Keywords: Lifecycle, Service, Simulation |
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Abstract : This paper proposes ISCL, Integrated Service CAD and Life cycle simulator. ISCL plays the role of CAD/CAE tools for product design in Product Service Systems (PSSs) design. In ISCL, the service CAD supports systematic generation of alternative PSSs based on service modeling, and LCS analyzes their economic and environmental performances. The current study applies ISCL to the design of a PSS that includes functional upgrading service of a product, whose life cycle costs are sensitive to both its functional obsolescence and physical deterioration. Performances of alternative PSSs are investigated under different market and technology conditions. |
| Product Modularity for Life Cycle Design |
| Y. Umeda, S. Fukushige, K. Tonoike, S. Kondoh / H. Yoshikawa (1) |
| STC A, 57/1/2008, P.13 |
| Keywords: Lifecycle, Geometric modelling, Modular design |
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Abstract : Modular design is an important elemental technique in life cycle design for improving, e.g., maintainability, upgradability, reusability, and recyclability. Appropriate modular structure differs according to applied life cycle options; e.g., while the modular structure for recycling should be based on material kinds, the structure for upgrading should be based on functions to be obsolete. This paper proposes a method for determining modular structure by aggregating various attributes related to a product life cycle and evaluating geometric feasibility of modules. This paper also illustrates the prototype system that implements the proposed method and a case study of a printer. |
| Carbon Emissions and CES TM in Manufacturing |
| J. Jeswiet (1), S. Kara (2) |
| STC A, 57/1/2008, P.17 |
| Keywords: Energy, Carbon Emissions, Manufacturing |
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Abstract : The manufacturing of a product is connected directly to the amount of carbon emitted in producing electrical energy for that manufacturing process. A new, simple Carbon Emission Signature, CESTM, is proposed. Knowing the CES for a power grid and the energy needed to make a part, the carbon emitted can be found. Examples of single point turning and open die forging are given. Knowing the total carbon emitted for a product, a manufacturer can to place a Green House Gas label on each product. A customer can then see the amount of Green House Gas emitted in making the product. |
| Assessing Social Impacts in a Life Cycle Perspective — Lessons Learned |
| M. Hauschild, L.C. Dreyer, A. Joergensen |
| STC A, 57/1/2008, P.21 |
| Keywords: Lifecycle; Sustainable development; Social impacts |
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Abstract : In our globalised economy, important stakeholder groups nowadays hold companies responsible for the social impacts they cause in their product chain through activities like child labour, corruption or discrimination of employees. Many companies thus see themselves in need of a tool which can help them make informed decisions about their social impacts throughout the life cycle of their products. The paper presents lessons learned from four years of work with industry on development of a methodology for social Life Cycle Assessment and implementation in the industrial product chain. The Social LCA methodology supplements the traditional environment-oriented LCA and the life cycle costing tools in support of sustainability management addressing all three pillars of sustainability: people, planet and profit. |
| Meeting the 2050 carbon target for paper by print removal |
| T.A.M. Counsell, J.M. Allwood (2) |
| STC A, 57/1/2008, P.25 |
| Keywords: Reuse, Removal, Print |
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Abstract : 1-2% of global carbon emissions arise in paper production, but the EU plans a 60% cut by 2050. Known process improvements give a 30% cut, but demand may double by 2050: can paper be re-used without recycling by print removal? Three techniques have been developed: abrasion operating in an adhesive wear regime; longer wavelength lasers can ablate toner-print; a solvent can effectively dissolve toner. Energy analysis shows that print removal requires around 10% of the energy required for a new sheet and if this method supplies 80% of future demand, the 2050 carbon target could be achieved. |
| Folding Assembly of Micro-actuators |
| S.G. Kim (2), Z. Traina, H.W. Lee |
| STC A, 57/1/2008, P.29 |
| Keywords: Assembly, Actuator, Piezo-electric |
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Abstract : A muscle-inspired linear actuator that combines many piezoelectric micro-actuator “cells” into a single functional unit is designed and fabricated via folding assembly technique. A bow shaped epoxy beam structure amplifies the very small displacement of a thin film Lead Zirconate Titanate (PZT) beam, generating a large orthogonal contractive displacement of 15.24 µm in a footprint of 515 µm. Then, 3 sets of 3 actuator cells are assembled out-of-plane by folding about thin gold hinges connecting each set. With the folded triplet array, an unblocked displacement of 5.16 µm and blocking force of 6.31 µN were obtained. |
| A novel gripper for limp materials based on lateral Coanda ejectors |
| T.K. Lien (2), P.G.G. Davis |
| STC A, 57/1/2008, P.33 |
| Keywords: Robot, Handling, Coanda-effect |
|
Abstract : Limp materials like textiles, leather, porous tissues, meat and fish fillets do represent challenges in automation. A universal gripping principle that is usable for all these materials is not known. This paper describes a new gripping principle based on a novel Coanda effect ejector meeting these challenges. This ejector allows the construction of a slim, plate shaped vacuum gripper with multiple independent suction heads. Each suction head is powered by a newly patented lateral Coanda ejector that ensures gripping power on all soft or porous materials. The paper presents results of investigations on important parameters of the Coanda effect gripper. |
| A Programming system for Robot-based Remote-Laser-Welding with Conventional Optics |
| G. Reinhart (1), U. Munzert, W. Vogl |
| STC A, 57/1/2008, P.37 |
| Keywords: Robot, Programming, Remote-Laser-Welding |
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Abstract : The authors present a task oriented programming system for Remote-Laser-Welding (RLW) with conventional optics, which considers real workpiece data and process limits for the calculation of robot paths. This approach relies on an Augmented-Reality-based user interface for effective 3D-interaction and task definition. A powerful task and motion planning system has been developed, that transfers task-descriptions to optimized, executable robot operations. The resulting system offers fast and efficient spatial interaction methods that allow even novel users to quickly define operations on a task-level. The approach simplifies and accelerates the programming process, consequently leading to a reduction of cycle time for a RLW-task by more than 30%. |
| Robust Control of Force Coupled Human-Robot-Interaction in Assembly Processes |
| J. Krüger, D. Surdilovic / F-L. Krause (1) |
| STC A, 57/1/2008, P.41 |
| Keywords: Co-operative Assembly, Robot, Man-machine system |
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Abstract : Flexibility and changeability of assembly processes require a close interlinkage between the worker and the automated assembly system. The interaction between human and robot improves complex assembly processes, particularly when a robot can be guided by a worker and the robot provides power assistance to the worker. The close physical contact and the direct coupling of forces of human and robot necessitate a stable and robust interaction control. This paper describes a framework developed for a robustly stable control design for interactive robots serving as intelligent assist systems for flexible and highly adaptable assembly. |
| Product Variety and Manufacturing Complexity in Assembly Systems and Supply Chains |
| S.J. Hu (2), X. Zhu, H. Wang, Y. Koren (1) |
| STC A, 57/1/2008, P.45 |
| Keywords: Assembly, Customization, Complexity |
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Abstract : Mixed-model assembly systems and modular supply chains are enablers to high product variety. However, as variety gets very high, the assembly and supply processes can become very complex. In assembly systems, the complexity may cause human errors and in turn impacts system performance. The complexity also impacts supply chain configuration and inventory control policy. This paper proposes a unified measure and models of complexity to assist in designing systems with robust performances. Complexity is defined as an entropy function of product variety and models are developed to describe the complexity propagation in multi-stage assembly systems and multi-echelon supply chains. Applications of the models are presented for complexity mitigation. |
| Degradation state model-based prognosis for proactively maintaining product performance |
| B. Iung (2), M. Monnin, A. Voisin, p. Cocheteux, E. Levrat |
| STC A, 57/1/2008, P.49 |
| Keywords: Maintenance, Failure Model, Prognosis |
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Abstract : Maintenance plays now a critical role in manufacturing for achieving important cost savings and competitive advantage while preserving product conditions. It suggests moving from conventional maintenance practices to predictive strategy. Indeed the maintenance action has to be done at the right time according the component Remaining Useful Life (RUL) assessed by a prognosis process. The accuracy of the RUL is mainly depending on the relevance of the component degradation model used for prediction. In that way, this paper aims at discussing an efficient degradation model taking into account the operational conditions, the health monitoring and the maintenance actions. This model is based on discrete states associated with the degradation levels, and on a cumulative function modelling the transition time between successive states. The model is implemented by means of Stochastic Activity Networks (SAN). The feasibility and added value of such degradation models for prognosis is then highlighted through experimentations made on manufacturing TELMA platform |
STC C |
| Ultrasonic Deep Hole Drilling in Electrolytic Copper ECu 57 |
| U. Heisel (1), J. Wallaschek, R. Eisseler, C. Potthast |
| STC C, 57/1/2008, P.53 |
| Keywords: Drilling, Ultrasonic, Deep hole |
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Abstract : At present the machining of highly ductile electrolytic copper ECu 57 with gun drills is carried out at very low feed values, as the material tends to form very long and unfavourable chips. In addition, high frictional forces on the guide rails cause high torsional strain on the gun drill. This paper reports on first results of ultrasonically assisted deep hole drilling in ECu 57 with tools of 5 mm diameter. The actuator system for exciting axial vibrations in the ultrasonic range is described and experimental results which were obtained in cutting tests are reported. Particular emphasis is put on the improvements compared with the conventional drilling technology without superimposed vibrations. The effect of different input amplitudes is investigated in detail. The performance criteria are drilling moment, surface quality, chip form as well as the surface zone. By optimising the vibration amplitude, cutting speed and feed, the machining result was improved compared with conventional machining, and at the same time the stability of the machining process was simultaneously increased. |
| Analysis of 3D Elliptical Vibration Cutting with Thin Shear Plane Model |
| E. Shamoto (2), N. Suzuki, R. Hino |
| STC C, 57/1/2008, P.57 |
| Keywords: Cutting, Analysis, Elliptical vibration cutting |
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Abstract : Simple analytical models of three dimensional (3D) elliptical vibration cutting are developed in order to simulate the cutting process quickly and to understand the basic mechanics. The elliptical vibration cutting has recently been applied in industry mainly to ultraprecision machining of dies and molds, where the vibration locus is not generally perpendicular to the cutting edge and thus all directions of shear, chip flow and cutting force have the 3D components. Therefore, the 3D elliptical vibration cutting models are developed, and the basic cutting mechanics are discussed in the present research. |
| 3D Finite Element Analysis of Tool Wear in Machining |
| A. Attanasio, E. Ceretti (2), S. Rizzuti, D. Umbrello, F. Micari (1) |
| STC C, 57/1/2008, P.61 |
| Keywords: Cutting, Wear, FEM. |
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Abstract : The paper is focused on the 3D numerical prediction of tool wear in metal cutting operations. In particular, an analytical model, able to take into account the diffusive wear mechanism, was implemented through a specific subroutine. Furthermore, an advanced approach to model heat transfer phenomena at the tool-chip interface was included in the numerical simulation. The adopted simulation strategy gave the possibility to properly evaluate the tool wear. The 3D FEM results were compared with some experimental data obtained turning AISI 1045 steel using uncoated WC tool; a good agreement was found out. |
| Thermal Fields in Orthogonal Cutting of AISI 4140 Steel |
| P.J. Arrazola (3), I. Arriola , M.A. Davies (2), A.L. Cooke, B.S. Dutterer |
| STC C, 57/1/2008, P.65 |
| Keywords: Machinability, Temperature measurement, Tool wear |
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Abstract : The micro-scale temperature fields in the cutting of two AISI 4140 steels with different machinability ratings were measured. A custom infrared microscope was constructed; each pixel was calibrated separately to reduce measurement uncertainty. Orthogonal cutting experiments were performed on a high speed machining center with surface speeds up to 500 m/min and uncut chip thicknesses ranging from 0.1 mm to 0.3 mm. The results indicate that in certain critical regions of the thermal field, improved machinability correlates with significant reductions in temperature that exceed measurement uncertainties. Such micro-scale temperature measurements will help to design materials with further improved machinability. |
| Development of Infrared Radiation Pyrometer with Optical Fibers— Two-color Pyrometer with Non-contact Fiber Coupler |
| T. Ueda (2), M. Sato, A. Hosokawa, M. Ozawa |
| STC C, 57/1/2008, P.69 |
| Keywords: Cutting, Temperature, IR Measurement |
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Abstract : A new type of pyrometer is developed, in which two optical fibers are used to accept and transmit the infrared energy. These two fibers are connected using a non-contact fiber coupler. In turning, the incidence face of one optical fiber which is embedded in a rotating workpiece accepts the infrared rays radiated from the cutting tool and emits it at the other face. The infrared energy is accepted by the other optical fiber which is fixed at the pyrometer and led to the two-color detector. In endmilling, the temperature history of CBN tool face during cutting is measured, where the fiber is embedded in the endmill. |
| Hard Turning with Variable Micro-Geometry PcBN Tools |
| T. özel (1), Y. Karpat (2), A. Srivastava (3) / B. Kaftanoglu (1) |
| STC C, 57/1/2008, P.73 |
| Keywords: Hard machining, Tool, Edge geometry |
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Abstract : This paper presents investigations on hard turning with variable edge design PcBN inserts. Turning of hardened AISI 4340 steel with uniform and variable edge design PcBN inserts is conducted, forces and tool wear are measured. 3-D finite element modelling is utilized to predict chip formation, forces, temperatures and tool wear on uniform and variable edge micro-geometry tools. Predicted forces and tool wear contours are compared with experiments. The temperature distributions and tool wear contours demonstrate the advantages of variable edge micro-geometry design. |
| Analysis of Residual Stresses Induced by Dry Turning of Difficult-to-machine Materials |
| J.C. Outeiro, J.C. Pina, R. M’Saoubi (2), F. Pusavec, I.S. Jawahir (1) |
| STC C, 57/1/2008, P.77 |
| Keywords: Modelling, Machining, Residual Stresses. |
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Abstract : Critical issues in machining of difficult-to-cut materials are often associated with short tool-life and poor surface integrity, where the resulting tensile residual stresses on the machined surface significantly affect the component’s fatigue life. This study presents the influence of cutting process parameters on machining performance and surface integrity generated during dry turning of Inconel 718 and austenitic stainless steel AISI 316L with coated and uncoated carbide tools. A three-dimensional Finite Element Model was also developed and the predicted results were compared with those measured. |
| An Enhanced Analytical Model for Residual Stress |
| I. Lazoglu, D. Ulutan, B.E. Alaca, S. Engin / B. Kaftanoglu (1) |
| STC C, 57/1/2008, P.81 |
| Keywords: Residual Stresses, Simulation, Machining |
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Abstract : The predictions of residual stresses are most critical on the machined aerospace components for the safety of the aircraft. In this paper, an enhanced analytic elasto-plastic model is presented using the superposition of thermal and mechanical stresses on the workpiece, followed by a relaxation procedure. Theoretical residual stress predictions are verified experimentally with X-ray diffraction measurements on the high strength engineering material of Waspaloy that is used critical parts such as in aircraft jet engines. With the enhanced analytical model, accurate residual stress results are achieved, while the computational time compared to equivalent FEM models is decreased from days to seconds. |
| In-Process Information Storage in the Surface by Turning Operation |
| B. Denkena (1), D. Boehnke, C. Spille, R. Dragon |
| STC C, 57/1/2008, P.85 |
| Keywords: Information, Microstructure, Turning |
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Abstract : Information about a workpiece is normally stored separately from it, e.g. in databases or on paper. This can be overcome by storing the information during processing directly on the surface, which enables its use in every stage of the lifecycle. To achieve this, microstructures are used to carry coded information. These microstructures are produced by a piezo-electric driven turning tool which allows a motion perpendicular to the surface up to a frequency of 6 kHz. Sophisticated methods of signal processing and an optimized turning process are used for data storage with high data density and data integrity even when the surface is partly destructed. |
| Surface Finishes from Turning and Facing with Round Nosed Tools |
| T.H.C. Childs (1), K. Sekiya, R. Tezuka, Y. Yamane, D. Dornfeld (1), D-E. Lee, S. Min, P.K. Wright |
| STC C, 57/1/2008, P.89 |
| Keywords: Precision, Machining, Surface roughness |
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Abstract : The range of surface roughnesses, and particularly the minimum roughnesses, achievable mainly with cemented carbide but also with single crystal diamond round nosed turning and facing inserts, has been experimentally studied, machining aluminium on engineering and precision lathes. Insert edge sharpness and roughness measurements and characteristic variations with feed rate of machined surface profile are presented. When machine tool limits are avoided, Rz values down to 0.02 times the insert edge radii have been obtained. |
| Dynamics of Chip Formation during Orthogonal Cutting of Titanium Alloy Ti-6Al-4V |
| G. Byrne (1), M. Cotterell (3) |
| STC C, 57/1/2008, P.93 |
| Keywords: Chip Formation; Titanium Alloy; Shear Strain |
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Abstract : Polished and etched disks of titanium alloy Ti-6Al-4V were machined in a series of continuous and interrupted orthogonal cutting tests on a specially adapted lathe. A high speed imaging system with a microscope lens and strobed copper-vapour laser illumination system enabled direct observation of the chip formation zone at a recording rate of 24,000 frames/s. The chip formation cycle was recorded for cutting speeds from 4 to 140 m/min. Segmented chips were observed throughout. Image analysis of the recorded video sequences examined the resulting chip segment geometry, the segmentation frequency and the critical strain required to initiate shear band formation. |
| Development of a Thermomechanical Cutting Process Model for Machining Process Simulations |
| E. Budak (2), E. Ozlu |
| STC C, 57/1/2008, P.97 |
| Keywords: Process Model, Cutting Force, Machining Simulation |
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Abstract : A thermomechanical model for cutting processes is presented. The deformation in the shear zone is represented using Johnson-Cook material model. The rake contact is modeled using sticking and sliding zones, and their lengths are also predicted. The parameters of the material model and the friction coefficient on the rake are directly identified from a few number of orthogonal cutting tests. The model can predict cutting forces, shear angle and stress, pressure distribution and contact lengths on the rake face and temperature distribution. The application of the model to common operations such as turning and multi axis milling is also presented with experimental verification, and satisfactory results are obtained. |
| Model development for the prediction of surface topography generated by ball-end mills taking into account the tool parallel axis offset. Experimental validation |
| M. Arizmendi, J. Fernandez (3), L.N. Lopez de Lacalle, A. Lamikiz, A. Gil, J.A. Sanchez, F.J. Campa, / H. Chandrasekaran (1) |
| STC C, 57/1/2008, P.101 |
| Keywords: Ball-end milling, surface topography, tool parallel axis offset |
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Abstract : This paper presents a model for the topography prediction of ball-end milled surfaces, considering the tool parallel axis offset. First, the equations of cutting edges trajectories and the envelope equation of the material swept by the tool are derived. Later, the trajectories are cut by planes perpendicular to the feed direction obtaining a set of transcendental equations that are solved by transforming them to polynomial equations through Chebyshev expansions. This procedure presents the advantage on previous models in literature of not requiring any starting point to achieve the solution. Finally, experimental results are presented and compared to the model predictions. |
| Increasing Tool Life by Adjusting the Milling Cutting Conditions According to PVD Films’ Properties |
| K.-D. Bouzakis (1), S. Gerardis, G. Katirtzoglou, S. Makrimallakis, N. Michailidis (2), E. Lili |
| STC C, 57/1/2008, P.105 |
| Keywords: PVD coatings, wear, milling |
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Abstract : The coated tools cutting performance in up and down milling depends significantly on the PVD film material properties. The related wear mechanisms at various cutting speeds can be sufficiently explained considering the developed tool loads and the non-linear coating impact resistance versus temperature. Various PVD coated cemented carbide inserts were tested at different cutting conditions. The corresponding cutting loads and temperatures were determined by FEM simulations and the films’ impact resistance by impact tests. A correlation between the impact resistance and the cutting performance at corresponding temperatures contributed to the optimum adjustment of the cutting parameters to the film properties. |
| A Study on Initial Contact Detection for Precision Micro-mold and Surface Generation of Vertical Side Walls in Micromachining |
| S. Min, H. Sangermann, C. Mertens, D. Dornfeld (1) |
| STC C, 57/1/2008, P.109 |
| Keywords: Micromachining, Surface, Acoustic emission |
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Abstract : The surface quality and the dimensional accuracy are important criteria for micro-mold production, specially for microfluidic devices. Important cutting parameters that affect the quality of vertical side walls created by the peripheral cutting edge in micro-end-milling operations were identified. Surface roughness and form error were used to define the quality of side walls on stainless steel and aluminum workpieces. An acoustic emission sensor was used to detect initial contact between a tool and a workpiece for higher dimensional accuracy where the referencing is a critical element for precision micromachining feature creation. |
| Modelling the Cutting Edge Radius Size Effect for Force Prediction in Micro Milling |
| G. Bissacco, H.N. Hansen (1), J. Slunsky |
| STC C, 57/1/2008, P.113 |
| Keywords: Micromachining, Modelling, Cutting |
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Abstract : This paper presents a theoretical model for cutting force prediction in micro milling, taking into account the cutting edge radius size effect, the tool run out and the deviation of the chip flow angle from the inclination angle. A parameterization according to the uncut chip thickness to cutting edge radius ratio is used for the parameters involved in the force calculation. The model was verified by means of cutting force measurements in micro milling. The results show good agreement between predicted and measured forces. It is also demonstrated that the use of the Stabler’s rule is a reasonable approximation and that micro end mill run out is effectively compensated by the deflections induced by the cutting forces. |
| Methodology for Evaluation of Centrifugal Force Resistance of HSC-Tools by Analyzing Tool Body Deformation and Cutting Edge Offset |
| E. Abele (2), R. Hoelscher, J. Hohenstein |
| STC C, 57/1/2008, P.117 |
| Keywords: Tool Reliability, Safety, Quality |
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Abstract : For high speed milling operations the most critical load is caused by centrifugal force. The maximum operational speed has to be determined to ensure centrifugal force resistance without over-dimensioning HSC-tools. Hence, resource intensive burst tests have to be executed. This paper demonstrates a non-destructive methodology to qualify tools for high speed milling. As our research shows, it is possible to estimate the maximum operational speed by analyzing the characteristics of elastic and plastic tool body enlargement and cutting edge displacement. In addition, it will be discussed how work piece quality can be improved by considering the cutting edge offset. |
| Tool Condition Monitoring in Micromilling Based on Hierarchical Integration of Signal Measures |
| K. Jemielniak (1), S. Bombinski, P.X. Aristimuno |
| STC C, 57/1/2008, P.121 |
| Keywords: Tool condition, monitoring, micromilling |
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Abstract : This paper presents a tool wear monitoring strategy in micro-milling of cold-work tool steel, 50 HRC with a ball endmill d=0.8mm. The is strategy based on a large number of AE and cutting forces signal features and a hierarchical algorithm. In the first stage of the algorithm, the tool wear is estimated separately for each signal feature. In the second stage, the results obtained in the first stage, are integrated into the final tool condition evaluation. The obtained results prove that the proposed algorithm enables reliable evaluation of tool wear in spite of strongly disturbed signal features. |
| Development of a New Lean Lubrication System for Near Dry Machining Process |
| T. Aoyama (2), Y. Kakinuma, M. Yamashita, M. Aoki |
| STC C, 57/1/2008, P.125 |
| Keywords: Lubrication, Cutting, Environmental |
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Abstract : The Minimal Quantity of Lubricant supply (MQL) technique has been applied to environmental friendly machining processes. However, in the MQL technique, a large volume of oil mist is discharged to the environment. In this paper, a new lean lubrication system for a near dry machining process called “Direct Oil drop Supply system (DOS)” is proposed. The performance of the DOS technique was evaluated by the milling processes. The DOS technique can supply a very small oil drop directly to the cutting edge without making oil mist, and the DOS shows almost same machining performances compared to the MQL technique. |
| Effectiveness and resolution of tests for evaluating the performance of cutting fluids in machining aerospace alloys |
| D.A. Axinte, L. De Chiffre (1) |
| STC C, 57/1/2008, P.129 |
| Keywords: Machining, fluid, aerospace alloy |
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Abstract : The paper discusses effectiveness and resolution of five cutting tests (turning, milling, drilling, tapping, VIPER grinding) and their quality output measures used in a multi-task procedure for evaluating the performance of cutting fluids when machining aerospace materials. The evaluation takes into account the following process output measures: tool wear, cutting forces, torque, spindle power, geometrical accuracy, texture and integrity of workpiece surface. Using statistics, through calculation of the Hellinger distance, the resolution given by experimental data was evaluated and a comparison of robustness in ranking the performance of cutting fluids based on different output measures and cutting tests is presented. |
STC Dn |
| Modularisation as an Enabler for Cycle Economy |
| G. Seliger (1), M. Zettl |
| STC Dn, 57/1/2008, P.133 |
| Keywords: Manufacturing, Module, Product |
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Abstract : Modularization proves to be a chance for increasing the use productivity of resources by enabling multiple usage phases sometimes even in different applications. A module configuration software-tool has been developed for finding an appropriate modular product structure considering life-cycle criteria. A mathematical model has been implemented to solve this multi-criterion optimization task. The application of the software-tool is presented in a case study. The vision of developing and producing modular products in sustainable value creation networks is introduced. |
| Incorporating Probabilistic Model of Customers’ Preferences in Concurrent Engineering |
| Y. Wang, M.M. Tseng (1) |
| STC Dn, 57/1/2008, P.137 |
| Keywords: Product design, Concurrent Engineering, Customers’ preferences |
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Abstract : Concurrent engineering has been generally accepted as an important approach to reduce time to market. For years, the focus of concurrency has been design and manufacturing. With customers’ inputs become more crucial for product development, incorporating customers’ preferences into the design process has become significant in the continuing quest for reducing time to market. Because customers’ preferences involve intricate interdependency on factors such as product attributes, deterministic methods often fall short of representing and manipulating their probabilistic nature. This paper presents a probabilistic model that could continuously incorporate and adapt customers’ preferences into the concurrent engineering methodology. |
| Platform Differentiation Plan for Platform Leverage across Market Niches |
| Y.L. Cai, A.Y.C. Nee (1), W.F. Lu |
| STC Dn, 57/1/2008, P.141 |
| Keywords: Product design methodology, design method, product platform leverage strategy |
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Abstract : This paper presents a methodology of proposing a platform differentiation plan (PDP) to provide a platform leverage strategy across market niches. PDP is designed to provide a consistent balance between mutual differentiation and components sharing for the leveraged platforms at the early product planning stage. Two indices, i.e. differentiation index (DI) and commonality opportunity index (COI), are presented to represent the dimensions of product platform differentiation and commonality respectively. Through a case study of electronic test equipment (ETE), the usefulness of PDP for the platform leverage strategy across market niches is demonstrated. |
| Functional requirement specification in the packaging development chain |
| E. Lutters (2), R. Ten Klooster |
| STC Dn, 57/1/2008, P.145 |
| Keywords: Development methodology, Requirement management, Packaging development cycle |
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Abstract : As it is clear that the full packaging life cycle —at least partially- coincides with the product life cycle, both cycles are interwoven. Each has a network of functional requirements, with specific hierarchic propensities. These networks overlap, with prevailing hierarchies playing important roles in combined product/packaging development cycles. This publication describes the role of functional requirements in the complex context of product/packaging life cycles and shows ways to adequately uncover functional requirement specifications besides, or even instead of, technical specifications. A working method is presented, guiding product/packaging development cycles based on structured functional hierarchies. The applicability of the method is shown in a case study. |
| Use of Opposite-Relation Lexical Stimuli in Concept Generation |
| I. Chiu, L.H. Shu (2) |
| STC Dn, 57/1/2008, P.149 |
| Keywords: Conceptual design; Design method; Design stimuli |
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Abstract : Design description and modeling is widely performed using form-independent functions represented by words in the lexical category of verbs. We have been studying the use of lexical, or word, stimuli in generating design concepts. In this paper, we describe an experiment where participants were provided with problems and stimuli sets consisting of verbs with meanings similar to and opposite to the functional requirements. For all problems, participants were observed to select opposite terms despite their less apparent connection to the problem, even though similar, more obvious terms were present. Results suggest a possible increase in concept novelty when using opposite terms. |
| Computer Aided Manufacturability Analysis:Closing the knowledge gap between the designer and the manufacturer |
| G. Molcho, Y. Zipori, R. Schneor, O. Rosen, D. Goldstein, M. Shpitalni (1) |
| STC Dn, 57/1/2008, P.153 |
| Keywords: Knowledge management, CAPP, Manufacturing. |
|
Abstract : Manufacturing today is marked by increased competition and dispersed global organization, thus necessitating enhanced collaboration among designers and manufacturers. Nevertheless, while Design for Manufacturability (DFM) has been the subject of in-depth research over the past decades, the supporting software solutions have not as yet matured. In this paper we present a holistic approach and supporting software tool, termed the Computer Aided Manufacturability Analysis (CAMA) tool, for capitalizing on available manufacturability knowledge. This is achieved by closing the knowledge loop between the design and manufacturing environments. CAMA captures the knowledge in a structured manner and incorporates this knowledge within the product design tools (CAD systems), thus enabling improved product timeliness and profitability. CAMA represents proof of concept and constitutes a demonstrative prototype of an adaptive and open DFX tool. It is based on industrial surveys of the Knowledge, Information and Data (KID) flows in CAD, CAPP and CAM processes within the manufacturing outsourcing environment. CAMA differs from other approaches in that it is an open system that enables continuous and intuitive capture, modification and implementation of updated manufacturability KID. |
| Geometrical Reliability of Overconstrained Mechanisms with Gaps |
| A. Ballu, J.-Y. Plantec, L. Mathieu (1) |
| STC Dn, 57/1/2008, P.159 |
| Keywords: Reliability Design, Product Modelling, Tolerance Analysis |
|
Abstract : Reliability design relates generally to simulation of fatigue strength, thermal effects... not to simulation of geometrical variations, i.e. tolerancing. The variables for geometrical reliability are manufacturing, gap and functional deviations. In case of isoconstrained mechanisms, the linear expression of dependencies between these variables allows to calculate failure probability. For overconstrained mechanisms, these linear expressions are not applicable for the whole behaviour of the mechanism; nevertheless, they are applicable for each particular configuration of contacts. The different configurations represent events taken into account in a numerical evaluation assumed by the Form-Sorm method. A case study, with numerical results, illustrates and validates the chosen process |
| Design Knowledge Extraction from Scenario-based Databases Using Associative Search Engine for FR-induced Decisions |
| M. Nakao (2), K. Tsuchiya, K. Iino |
| STC Dn, 57/1/2008, P.163 |
| Keywords: design method; knowledge management; decision making |
|
Abstract : The authors set the functional requirement of “Reduce your own risk” and ran sessions of associative search to extract useful knowledge from databases. Ninety engineers found the most analogous knowledge using the associative search engine “GETA/IMAGINE” on scenario-based databases “Failure Knowledge Database” and “100 Scenarios of Failure.” Above 60% of their risk concern cases successfully reached the most analogous accident cases or failure scenarios from either database in about 10 minutes. Associative search can aid the designer in selecting design solutions for the functional domain. |
| Virtual Sculpting With Surface Smoothing Based On Level Set Method |
| M.C. Leu (2), W. Zhang |
| STC Dn, 57/1/2008, P.167 |
| Keywords: Computer Aided Design, Surface Smoothing, Level Set Method |
|
Abstract : This paper presents a surface smoothing technique based on the level set method. The triple-dexel data used to represent the generated model in virtual sculpting is converted into distance field data by identifying spatial grid points close to the model’s boundary surface and calculating their Euclidean distance values. The surface is smoothed by solving the level set differential equation with mean curvature flow using a fast and robust numerical scheme. Examples are given to demonstrate the effectiveness of the surface smoothing operation for virtual sculpting. |
| Virtual environments for dynamically reconfigurable Concurrent/Collaborative Engineering “virtual†teams |
| G.D. Putnik, p. Goncalves, A. Sluga (2), M.M. Cunha |
| STC Dn, 57/1/2008, P.171 |
| Keywords: Virtual Reality, Manufacturing Systems, Dynamic Reconfiguration |
|
Abstract : The paper presents a hypothesis, and its experimental validation, on virtual environments, i.e. Virtual Reality based interfaces, which hide the real appearance of their interlocutors, as enablers, or facilitators, of performance of dynamically reconfigurable “virtual†teams in Concurrent/Collaborative Engineering. Design teams dynamic reconfiguration may either be a need for 1) their structural and functional optimization (e.g. for improving their productivity) or 2) to support dissipatedness of the design teams in Chaordic Manufacturing Systems. The effect virtual environments have on reducing the “set-up†time when switching from one interlocutor to another during the communication process is evaluated. The proof of the hypothesis is presented through a statistical evaluation of the experiment. |
| Improving decision-making by simulating and visualizing geometrical variation in non-rigid assemblies |
| R. Söderberg, C. Wickman, L. Lindkvist / G. Sohlenius (1) |
| STC Dn, 57/1/2008, P.175 |
| Keywords: Tolerancing, Virtual Reality, Design. |
|
Abstract : Customer demands on quality appearance as well as economical demands for shorter development time are increasing. Virtual concept verification is therefore becoming more and more important since an increasing number of decisions are based on digital models. This paper discusses visual quality appearance and presents the concept of geometrical and visual sensitivity along with tools for analysis and evaluation. Especially, a tool for non-rigid variation simulation and visualization is presented. It allows manufacturing and assembly deformations to be visualized with high level of realism long before any physical prototypes are being made. Different design concepts can thereby be compared in realistic environments. The quality of decisions based on digital models can thereby be improved. |
| A Rotary Flexural Bearing for Micromanufacturing |
| H.P Luo, B. Zhang (2), Z.X Zhou |
| STC Dn, 57/1/2008, P.179 |
| Keywords: Spindle, Finite Element Method, Rotary Flexural Bearing |
|
Abstract : This study proposes a design methodology for a novel rotary flexural bearing that is based on the motion principles of elastic flexures. The bearing is capable of providing rotational oscillations of one complete revolution and is characterized by potentially high repeatability, smooth motions, no mechanical wear and no lubrication requirements, no gaps or interfaces, zero maintenance, in addition to its compactness. From the structural characteristics and the basic working principles of the flexural bearings, the study provides a design analysis on the various aspects of the bearing, including material selection, stress analysis and calculations (such as non-linear finite element analysis, static and fatigue strength designs), motion error analysis and error reduction strategy, and parametric design, etc. |
| Integrated Bottom Up and Top Down Approach to Optimization of the Extrusion Process |
| T.H.J. Vaneker, G. van Ouwerkerk, K.E. Nilsen , P.T.G. Koenis, F.J.A.M. van Houten (1) |
| STC Dn, 57/1/2008, P.183 |
| Keywords: Aluminum Extrusion, Die Design, Design Optimization |
|
Abstract : Boal BV and the University of Twente participate in research projects focused on improvement of die design methods for aluminum extrusion dies. Within this research empirical knowledge is combined with insights gained from numerical process simulations. Design rules for improvements to the geometry and functionality of flat and porthole dies have been defined. For porthole dies this has led to enhanced die stability and significant reduction of scrap. For both flat and porthole dies an increase in production speed and a reduction of wear has been obtained. This paper will describe the scope of this research and present results achieved in industrial practice. |
STC E |
| Workpiece surface roughness and integrity after WEDM of Ti-6Al-4V and Inconel 718 using minimum damage generator technology |
| D.K. Aspinwall (2), S.L. Soo, A.E. Berrisford, G. Walder (3) |
| STC E, 57/1/2008, P.187 |
| Keywords: Electrical discharge machining (EDM), Titanium, Integrity |
|
Abstract : Following a brief review of EDM and its use on advanced aerospace alloys including workpiece integrity constraints, data are presented after machining Ti-6Al-4V and Inconel 718. Roughing and finishing (multiple trim cut) strategies were employed on two high specification machines with pulse generators designed to provide minimum workpiece integrity damage. Results include productivity, 3D topographic maps of workpiece surfaces, microstructural and microhardness depth profile data. Average recast thickness was <11um, several trim passes showing no apparent recast or damage. Similarly, no significant change in workpiece microhardness variation was observed with cracking confined to the recast layer. |
| Influence of the type and grain size of the electro-conductive phase on the Wire-EDM performance of ZrO2 ceramic composites |
| B. Lauwers (2), K. Brans, W. Liu, J. Vleugels, S. Salehi, K. Vanmeensel |
| STC E, 57/1/2008, P.191 |
| Keywords: Electrical Discharge Machining (EDM), Ceramic, Microstructure |
|
Abstract : This paper investigates the Wire-EDM behaviour of various newly developed electro-conductive ZrO2 ceramic matrix composites. The influence of the type and grain size of the second phase (WC, TiC and TiCN, from micro sized to nano sized grains) on the EDM material removal rate and obtained surface roughness is experimentally studied. This investigation is based on a design of experiments supported by a fundamental study of the material removal mechanisms. It is shown that a variation in grain size of the second phase material significantly influences the EDM performance, which can be largely related to the microstructure and the properties of the developed material. |
| Assessment of Abrasion-Assisted Material Removal in Wire EDM |
| I. Menzies, p. Koshy (2) |
| STC E, 57/1/2008, P.195 |
| Keywords: Abrasion, Wire EDM, Hybrid machining process |
|
Abstract : Machining speed and surface integrity continue to be issues of focus in current wire EDM research. In this light, the proof-of-concept of a hybrid wire EDM process that utilizes a wire embedded with electrically non-conducting abrasives is presented. Material removal in this novel process is realized through electrical erosion that is augmented by two-body abrasion. This is shown to bring about a significant improvement in the removal rate and generate surfaces with minimal recast material, in comparison to an equivalent wire EDM process. Implementation details and process characteristics are discussed. |
| Understanding Behavior of Machining Interface and Dielectric Molecular Medium in Nanoscale Electro-Machining |
| V. Kalyanasundaram, K.R. Virwani, D.E. Spearot, A.P. Malshe (2), K.P. Rajurkar (1) |
| STC E, 57/1/2008, P.199 |
| Keywords: Electrical discharge machining, Simulation, Nanoscale electrical breakdown |
|
Abstract : Recently, a repeatable and scalable nanoscale electro-machining (nano-EM) process to produce sub-20nm scale features has been demonstrated. In the presented research, the behavior of the liquid dielectric (n-decane) machining medium in nanoconfinement (<3nm) under physical boundary conditions is investigated using molecular dynamics simulation. Results show a four-fold increase in the density of n-decane indicating ‘quasi-solid’ behavior at the nano-EM machining interface, thereby acting as an effective charge transport medium between the nano-tool and the workpiece. The effect of such quasi-solid medium is demonstrated through the experimental observations of electrical breakdown at the sub-20nm scale interface. |
| Spectroscopic Measurement of Arc Plasma Diameter in EDM |
| A. Kojima, W. Natsu, M. Kunieda (2) |
| STC E, 57/1/2008, P.203 |
| Keywords: EDM, Temperature, Spectroscopy |
|
Abstract : This paper describes the spectroscopic measurement of arc plasma diameter in EDM. In order to determine the diameter of the arc plasma area where discharge current flows, radial temperature distribution in plasma generated by a single pulse discharge was measured using spectroscopy, and the area with high degree of ionization was determined. It was found that arc plasma completes expanding within a few micro seconds after dielectric breakdown, while the diameter of craters grows slowly in comparison with the expanding speed of the arc plasma. This new finding is different from conventional plasma expansion models established based on the observation of generated craters and unproven assumptions. Furthermore, increase in arc plasma diameter with increasing discharge current or gap width was quantified, enabling accurate simulation of discharge crater generation using the newly established heat source model. |
| Prediction of hypo eutectoid steel softening due to tempering phenomena in laser surface hardening |
| G. Tani (3), L. Orazi, A. Fortunato / R. Levi (1) |
| STC E, 57/1/2008, P.209 |
| Keywords: Laser beam machining (LBM), Modelling, Hardening |
|
Abstract : The paper presents a mathematical model for predicting material mechanical property variation, in laser hardening of hypo eutectoid steel, when the softening effects due to the overlapping trajectories are considered. This generally occurs during laser hardening of industrial parts, especially when wide areas have to be treated, due to the tempering phenomena. An original tempering model for the prediction of the hardness reduction is presented in this paper. The proposed model is integrated in a Laser Hardening simulation package, previously developed by the authors. Experimental activities are also presented to validate the model.
|
| Analysis of YAG Laser Lap-Welding of Zinc Coated Steel Sheets |
| M. Schmidt (3), A. Otto, C. Kägeler / M. Geiger (1) |
| STC E, 57/1/2008, P.213 |
| Keywords: Laser, Welding, In Process Measurement |
|
Abstract : Joining of coated steel sheets in an overlap configuration today has become an important manufacturing step in automotive production. But the assembly of functional structures using laser welding processes deals with several challenges. This paper presents a new approach to join coated steel sheets by using a fast frequency modulation of the laser power according to actual process states. Based on the analysis of optical process emissions, a control system is applied. Experimental results point out the interference of process oscillations with the external influence. They show that a well directed control of the welding process reduces its partially chaotic behaviour. |
| Analysis of Laser Micromachining in Silica Glass with an Absorbent Slurry |
| M. Mitsuishi (2), N. Sugita, I. Kono, S. Warisawa |
| STC E, 57/1/2008, P.217 |
| Keywords: Laser beam machining, Glass, 3 dimensional micromachining |
|
Abstract : The authors have investigated a method for machining a 3D microchannel in silica glass using a UV nanosecond pulsed laser and an absorbent slurry. 3D microstructures in glass materials are required for optical waveguides, microfluidic chips, etc. The depths of the grooves and holes produced in the silica glass were found to be proportional to the number of laser pulses. The material removal process in the proposed method was the melting of the glass by heat transfer from the absorbent particles, which were attached to the surface of the glass, providing for strong laser absorption. |
| Surface Finishing of Stainless Steels for Orthopedic Surgical Tools by Large-area Electron Beam Irradiation |
| A. Okada, Y. Uno, J.A. McGeough (1), K. Fujiwara, K. Doi, K. Uemura, S. Sano |
| STC E, 57/1/2008, P.223 |
| Keywords: Finishing, EBM, Stainless steel |
|
Abstract : Surgical tools and jigs are initially machined by multi-axis milling. Then surface finishing is carried out mainly by hand lapping. As these tools undergo repeated use, the removal of burrs, scratches and rust from the surfaces is also performed manually after each operation. These finishing processes are time-consuming and costly. In this study a new finishing method by large-area electron beam irradiation is proposed. EB with high energy density can be obtained without focusing the beam, and large-area EB can be used for instantly melting or evaporating the metal surface. Stainless steel for surgical tools and jigs was treated by the large-area EB irradiation method. The experimental results show that highly efficient surface smoothing of stainless steels by large-area EB irradiation may be achieved. In addition, the resistance to corrosion and blood repellency can be improved simultaneously with surface smoothing |
| Micro Electroforming of High-Aspect-Ratio Metallic Microstructures by Using a Movable Mask |
| D. Zhu (2), Y.B. Zeng |
| STC E, 57/1/2008, P.227 |
| Keywords: Deposition, Microstructure, Electroforming |
|
Abstract : A novel micro electroforming process, which targets the cost efficient fabrication of high-aspect-ratio metallic microstructures, is presented in this paper. An insulating mask with patterned features for localizing the deposition region moves periodically along the metal growth direction during electrodeposition instead of the traditional patterned photoresist mask coated on a substrate. The proposed technology offers some unique advantages such as re-using of mask and avoiding removal of photoresist. The current density distribution and metal deposition in the proposed process were studied. Typical high-aspect-ratio metallic microparts in the scale of several hundred microns have been produced. |
| Shape Deposition Manufacturing of Biologically Inspired Hierarchical Microstructures |
| M. Lanzetta (2), M.R. Cutkosky |
| STC E, 57/1/2008, P.231 |
| Keywords: Prototyping, Surface, Design |
|
Abstract : The applications of dry adhesives range from part handling in manufacturing to aids for human and robotic climbing. Nature provides inspiration in the hierarchical structures used by geckos and spiders to attach using Van der Waals forces. Among the challenges faced in creating synthetic dry adhesives are the need to conform to surfaces at length scales from centimeters to tens of nanometers and the need to create arrays of compliant asymmetric structures at the micro scale. Initial attempts from the literature are reviewed and a new approach based on a hybrid additive/subtractive prototyping technique called Shape Deposition Manufacturing (SDM) is proposed. |
| Metal Filled Resin for Stereolithography Metal Part |
| P.J. Bartolo (2), J. Gaspar |
| STC E, 57/1/2008, P.235 |
| Keywords: Stereolithography, metal, powder |
|
Abstract : A new route to produce metallic parts through stereolithography is explored in this work. Stereolithography of metallic materials consists of a UV curable metallic suspension prepared with a pre-polymer acting as the binder material, a photo-initiator, metallic powder and additives. The critical material and process parameters are investigated in order to identify appropriate photosensitive metallic suspensions for stereolithography, based on their rheological and photochemical properties. Two different types of resins, unsaturated polyester and epoxy resin were considered in this study, to get a better understanding of free radical, cationic and hybrid polymerisation mechanisms, being the photo-curing reactions carried out at different light intensities. The powder used was either tungsten carbide (WC) or cobalt (Co) with different powder sizes. |
| Characteristics of the Bond in Cu-H13 Tool Steel Parts Fabricated using SLM |
| O M Al-Jamal, S Hinduja (1), L Li (2) |
| STC E, 57/1/2008, P.239 |
| Keywords: Bonding, SLM, Dissimilar Metals |
|
Abstract : The paper is concerned with the fabrication of bi-metallic parts using a purpose-built rig and a Nd:YAG laser, the two materials being copper and H13 tool steel. Two types of bonds are identified and various characteristics of these bonds are studied. These include the microstructure using an optical and scanning electron microscopes, tensile strength and hardness of the bond. The diffusivity between copper and H13 tool steel is quantified by performing energy dispersive x-ray spectroscopy analysis. The successful fabrication of two samples, each containing both types of bonds, is described. |
| Study of Compression Properties of Topologically Optimized FDM Made Structured Parts |
| L.M. Galantucci (1), F. Lavecchia, G. Percoco |
| STC E, 57/1/2008, P.243 |
| Keywords: Rapid Prototyping, Design Optimization, Fused Deposition Modeling |
|
Abstract : Most Rapid Prototyping additive techniques are expensive and suffer from a lack of efficiency when massive products are to be manufactured. The authors propose to reduce the density of rapid prototyped parts, finding alternative building styles. Topologically optimized parts have been created with internal geometry, using a narrow-waisted structure that avoids the need for building supports. In order to characterise and study the behaviour of the obtained low density parts, an experimental plan has been designed and executed. The approach has been tested using a Fused Deposition Modelling machine, but it is of a general nature and can be applied to other layered manufacturing technologies that use supports, dealing with slow building of massive parts. |
STC F |
| Theory of Single Point Incremental Forming |
| P.A.F. Martins, N. Bay (1), M. Skjoedt, M.B. Silva |
| STC F, 57/1/2008, P.247 |
| Keywords: Sheet Metal, Formability, Single Point Incremental Forming |
|
Abstract : This paper presents a closed-form theoretical analysis modelling the fundamentals of single point incremental forming and explaining the experimental and numerical results available in the literature for the past couple of years. The model is based on membrane analysis with bi-directional in-plane contact friction and is focused on the extreme modes of deformation that are likely to be found in single point incremental forming processes. The overall investigation is supported by experimental work performed by the authors and data retrieved from the literature. |
| Process Window Enhancement for Single Point Incremental Forming |
| J.R. Duflou (2), J. Verbert, B. Belkassem, J. Gu, H. Sol, C. Henrard, A.M. Habraken |
| STC F, 57/1/2008, P.253 |
| Keywords: Incremental forming, Simulation, Multi-step toolpath |
|
Abstract : Single point incremental forming suffers from process window limitations which are strongly determined by the maximum achievable forming angle. Forming consecutive, intermediate shapes can contribute to a significantly enlarged process window by allowing steeper maximum wall angles for a range of part geometries. In this paper an experimentally explored multi-step toolpath strategy is reported and the resulting part geometries compared to simulation output. Sheet thicknesses and strains achieved with these multi-step toolpaths were verified and contribute to better understanding of the material relocation mechanism underlying the enlarged process window. |
| Warm Incremental Forming of Magnesium Alloy AZ31 |
| G. Ambrogio, L. Filice (2), G.L. Manco |
| STC F, 57/1/2008, P.257 |
| Keywords: Magnesium, Sheet metal, Warm Incremental Forming |
|
Abstract : Industrial application of Magnesium Alloy AZ31 is dramatically increasing due to the very competitive mechanical strength vs. weight ratio. On the other hand, AZ31 is very difficult to be formed at room temperature. In this study Incremental Forming of the above material is taken into account, with particular reference to formability limits. The role of the main process parameters on material formability was investigated through a wide experimental campaign and a rigorous statistical analysis. |
| Novel Forging Technology of a Magnesium Alloy Impeller with Twisted Blades of Micro-Thickness |
| J.H. Lee (3), S.H. Kang (3) / D.Y. Yang (1) |
| STC F, 57/1/2008, P.261 |
| Keywords: Magnesium, Forging, Near-net shaped Impeller |
|
Abstract : In this work, a novel forging technology has been developed to produce a magnesium alloy impeller with twisted blades of micro-thickness used in a fuel cell system. Due to the very complicated blades of the impeller, a specially designed split die was adopted for successful forging of the impeller. In this split die-set, the coherence of reinforcement ring and split dies is induced by forging pressure which increases with increasing forging load. Both the reinforcement ring and the split dies have appropriate tapers so that during the forging process they are consolidated to allow no gap between the split dies and are separated easily after forging. This novel technology can provide the near net-shaped impeller without the burr generation when split dies are used. Based on the newly developed technology, the impeller forging experiments were carried out using magnesium alloy AZ31 which had been microstructurally refined through ECAP. The tensile and thermal stability tests were carried out under various levels of temperature and strain rate to find optimum processing conditions for precision impeller forging. Finally, the changes in microstructure and microhardness at the various positions of the forged impeller were investigated to compare with those of the initial billet. It has thus been shown that the proposed new method is effective to achieve precision forging of a magnesium alloy with high precision. |
| Testing Formability in the Hot Stamping of HSS |
| P.F. Bariani (1), S. Bruschi (2), A. Ghiotti, A. Turetta |
| STC F, 57/1/2008, P.265 |
| Keywords: Sheet Metal, Formability, Hot Deformation, Phase Transformatio |
|
Abstract : This paper presents an innovative experimental procedure, based on Nakazima test, for evaluating the formability limits in the hot stamping of HSS which is capable of generating formability data suitable for an FE modelling of the process. The approach is based on two complementary tests which are aimed at evaluating the actual phase transformation kinetics for the material under deformation conditions and the combinations of microstructure, temperature and straining path that lead to localized necking or fracture. |
| Characterization of Yielding Behavior of Sheet Metal under Biaxial Stress Condition at Elevated Temperatures |
| M. Merklein, W. Hussnätter, M. Geiger (1) |
| STC F, 57/1/2008, P.269 |
| Keywords: Forming, Anisotropy, Temperature |
|
Abstract : The enhancement of material modeling in fields of sheet metal forming is essential for finite element based designing of processes and dimensioning of parts. Since new light weight materials, e.g. aluminum and magnesium wrought alloys show anisotropic and temperature-dependent forming behavior adequate testing methods and evaluation strategies have to be developed to obtain the reliable material data. For that purpose an experimental setup has been designed at the Chair of Manufacturing Technology which enables bi-axial tensile testing of sheet metal at elevated temperatures. In this paper the setup is introduced and the obtained results, i.e. experimentally determined yield loci and subsequent yield loci as a function of temperature are given for the well known aluminum alloy AA6016 as well as the magnesium alloy AZ31. |
| Limiting Strains of Sheet Metals Obtained by Pneumatic Stretching at Elevated Temperatures |
| F.K. Abu-Farha, N.A. Shuaib, M.K. Khraisheh, K.J. Weinmann (1) |
| STC F, 57/1/2008, P.275 |
| Keywords: Sheet Metal, Forming, Limiting Strain |
|
Abstract : As uniaxial tensile testing fails to represent the actual loading case in sheet metal forming, evaluation of limiting strains is largely based on FLD’s produced by the Marciniak and Nakazima methods. The accuracy of these methods is subject to uncertainties of the actual deformation state and friction conditions. In addition, they are impractical for studying formability at elevated temperatures, which is of prime importance in forming lightweight alloys. This work presents a detailed systematic methodology for assessing formability and limiting strains by pneumatic sheet metal stretching. The proposed approach is demonstratively applied to the AZ31 magnesium alloy at various conditions. |
| New Plastic Joining Method using Indentation of Cold Bar to Hot Forged Part |
| R. Matsumoto, S. Hanami, A. Ogura, H. Yoshimura, K. Osakada (1) |
| STC F, 57/1/2008, P.279 |
| Keywords: Forming, Plastic, Joining |
|
Abstract : A new plastic joining method for fixing bars with a hot forged plate is proposed in which bars kept at room temperature are directly indented into a high-temperature plate. The optimum conditions for the proposed plastic joining method are examined using a low alloyed steel bar and a carbon steel plate. It is possible to indent the bar to the plate without buckling or plastic deformation by keeping the plate above 850°C. The attained shear bonding stress of bar—plate is approximately 40% of the shear strength of the plate material. The bonding mechanism of the proposed plastic joining method is discussed from the viewpoints of seizure of the plate and mechanical clamping associated with the process. Furthermore, some applications of the proposed method are suggested. |
| Advances in Mechanical Joining of Magnesium |
| R. Neugebauer (1), C. Kraus, S. Dietrich |
| STC F, 57/1/2008, P.283 |
| Keywords: Magnesium, Joining, Dieless clinching |
|
Abstract : The application of conventional mechanical joining methods for joining magnesium parts is restricted by the limited formability of magnesium at room temperature. Dieless clinching is a new clinching method that works with a flat anvil as a counter tool, thus offering important benefits for the joining of magnesium. It is possible to decrease the heating time to one second or less, instead of three to six seconds with conventional clinching methods. This article discusses the mechanism and limits to possible heating time reduction and introduces new findings on the impact of adhesives between parts. |
| On the Thermo-mechanical Loads and the Resultant Residual Stresses in Friction Stir Processing Operations |
| G. Buffa, L. Fratini (2), S. Pasta, R. Shivpuri (2) |
| STC F, 57/1/2008, P.287 |
| Keywords: Friction stir welding; Residual stress; Microstructure |
|
Abstract : In Friction Stir Welding and Processing both a thermal flux and a mechanical action are exerted on the material determining metallurgical evolutions, changes in the mechanical behaviour and a complex residual stress state. In the paper, the metallurgical changes are examined through numerical simulation and experiments to highlight and distinguish the effects of thermal and mechanical loadings. A particular focus is on the residual stresses generated during the stir processing of AA7075-T6 aluminium blanks. The predictions of FE model are validated by experimental measurements. Lastly, this paper presents an in-process quenching of the processed blanks for improved mechanical properties and microstructure. |
| Energy Balance in Laser Based Free Form Heading |
| F. Vollertsen (1), R. Walther |
| STC F, 57/1/2008, P.291 |
| Keywords: Metal Forming, Laser, Model |
|
Abstract : For the production of micro parts having large local accumulation of material a size effect can be used: local melting by pulsed laser heating is used instead of a multi stage upsetting process. The principle of this laser free form melting process is described. The influence of pulsed energy on the cumulated volume is investigated by experiments. The efficiency is determined by an analytical model, which gives the basis for an understanding of the relevance of the different coupling and energy loss terms. It is shown that the assumption of an adiabatic process is correct at least as a first approximation and the change of coupling phenomena from anormal to Fresnel absorption can explain the observations. |
| Adhesive Wear in Deep Drawing of Aluminum Sheets |
| P. Groche (2), G. Nitzsche, A. Elsen |
| STC F, 57/1/2008, P.295 |
| Keywords: deep drawing, aluminum, adhesive wear |
|
Abstract : This paper focuses on the experimental validation of the common model for adhesive wear initiation by Czichos et al. for conventional aluminum deep drawing operations. A strip drawing test with a 90 degree bending process is used for the studies. The local contact conditions at the drawing edge are examined by analytical examination and numerical simulation on different degrees of refinement. Contact normal stresses and temperature profiles are investigated and correlated with the experimental observation of adhesive wear. |
| Evaluation of Tool Materials, Coatings and Lubricants in Forming Galvanized Advanced High Strength Steels (AHSS) |
| H. Kim, S. Han, Q. Yan, T. Altan (1) |
| STC F, 57/1/2008, P.299 |
| Keywords: Stamping, Tribology, Galling |
|
Abstract : The major objective of this study is to establish guidelines to select the optimum combination of die materials, coatings and lubricants in stamping galvanized AHSS (DP600, TRIP780 and DP980) for automotive structural parts. For this purpose, Finite Element Analysis (FEA) and various tribotests, e.g. Twist Compression Test (TCT), Deep Drawing Test (DDT) and Strip Drawing Test (SDT), were used. The results of this study helped to determine the critical interface pressure and temperature that initiate lubricant failure and galling in forming galvanized AHSS for a given die material and coating. |
| Finite Element Analysis of Die Wear in Hot Forging Processes |
| B.-A. Behrens / E. v. Finckenstein (1) |
| STC F, 57/1/2008, P.305 |
| Keywords: Forging; Wear; Finite Element Method (FEM) |
|
Abstract : Design optimization of hot forging dies requires an accurate estimation of die wear. The presented paper introduces a finite element model for wear estimation that includes the process related thermal effects on hardness of the tool material. Fundamental investigations concerning the hardness evolution due to thermal softening of the tool material are presented. To obtain necessary data for model calibration by means of statistical analysis, optical measurements are performed on several industrial forging dies. The introduced model is proved to be applicable in wear estimation of hot forging dies over a large number of operating cycles. |
| Tool for optimal design of manufacturing chain based on metalforming |
| M. Pietrzyk (2), L. Madej, S. Weglarczyk |
| STC F, 57/1/2008, P.309 |
| Keywords: Modeling, Flow stress, Strain localization |
|
Abstract : Complex approach to design of manufacturing processes based on considering the whole Life Cycle (LC) of material, including processing and exploitation stages, is presented in the paper. Modelling of the Life Cycle provides possibility to control the final product properties at the stage of manufacturing. It means that required properties and specific behaviour of product under exploitation conditions can be obtained by optimization at the stage of material processing. The concept of the design of the entire manufacturing chain is presented in the paper and the application to manufacturing of the connecting part made of modern bainitic steels is proposed. |
| Experimental Investigation of Embedding High Strength Reinforcements in Extrusion Profiles |
| M. Schikorra, A.E. Tekkaya (2), M. Kleiner (1) |
| STC F, 57/1/2008, P.313 |
| Keywords: Extrusion, Composite, Profile |
|
Abstract : Embedding reinforcement or functional wires in extruded profiles offers the potential to increase mechanical properties as well as the field of application. With improved strength and stiffness and an integrated function as deformation sensor or data transmitter the weight of space frame structures can be reduced substantially. To comprehend the general conditions when embedding the reinforcement and functional elements during the extrusion process, experimental extrusion investigations have been carried out for the analysis of signifi-cant process and tool geometry parameters. Extrusion with porthole dies, i.e. by feeding the elements over bridges inside the die in the aluminum base material flow, was studied to manufacture continuous reinforced, thin-walled, and hollow profiles. Special care was taken to ensure an accurate positioning in the transient material flow to prevent a loss of functional-ity by insufficient covering and loss of positioning caused by the die geometry or unequal temperature distri-bution inside the die. Studies on different reinforcement wires and wire ropes based on high strength steel are presented, showing an increasing process stability when using solid wires. General process restrictions are analyzed and process guidelines are presented based on exemplary extrusions. |
| Rolling of Functional Metallic Surface Structures |
| G. Hirt (2), M. Thome |
| STC F, 57/1/2008, P.317 |
| Keywords: Forming, Miniaturization, Rolling |
|
Abstract : Due to functional enhancement and beneficial product properties, surface structuring of large semi-finished products and part components becomes more important. Rolling of so called riblet structures for drag reduction on surfaces in fluid-dynamics is presented within this contribution. The examination of a novel roll structuring process via defined steel wire winding is the primary topic. Both practical experiments and numerical simulations of the riblet rolling process point out potentials and limitations of the new structuring approach. Rolling of uniformly shaped riblets with a lateral distance of less than 100 µm is assumed to be possible on large sheets in future. |
| Warm and Hot Punching of Ultra High Strength Steel Sheet |
| K. Mori (2), S. Saito, S. Maki |
| STC F, 57/1/2008, P.321 |
| Keywords: Warm and Hot Punching, Sheet Metal, Ultra High Strength Steel |
|
Abstract : Warm and hot punching using resistance heating was developed to improve the quality of sheared edges of an ultra high strength steel sheet. As the heating temperature increased, the depth of the shiny burnished surface on the sheared edge increased and that of the rough fracture surface decreased. The rollover depth and burr height of the sheared edge became large above 800 °C. Although the roughness of the burnished surface was almost constant, the roughness of the fracture surface increased from 650 °C. The punching load was extremely reduced by the heating, i.e. 40 % of the cold punching load at 650 °C and 15 % at 1070 °C. The local resistance heating of the shearing region was efficient for the warm and hot shearing. It was found that the warm and hot shearing of ultra high strength steel sheets is effective for improving the quality of the sheared edge and in reducing the shearing load. |
STC G |
| Virtual High Performance Grinding with CBN Wheels |
| C. Guo (2), S. Ranganath, D. McIntosh (3), A. Elfizy |
| STC G, 57/1/2008, P.325 |
| Keywords: Grinding, CBN, Optimization |
|
Abstract : The development of future products requires designing, manufacturing, and testing components in a virtual environment before hardware parts are actually made. This paper presents a generalized process simulation and multi-constraint optimization strategy for 5-axis grinding with CBN wheels to increase material removal rates while avoiding process problems such as damage to the machined surfaces and premature wheel failure. The wheel-workpiece engagement conditions under 5-axis grinding are extracted from a CAM system by geometrically processing the NC program, the wheel geometry and the part geometry. The interpreted geometric contact data are used in combination with empirical grinding models to predict physical process parameters such as forces, power, heat flux, and temperature. These parameters are then used as the decision variables in a multi-constraint optimization to optimize process parameters such as workspeed to reduce cycle time. |
| Experimental Analysis of Wheel/Workpiece Dynamic Interactions in Grinding |
| J.F.G. Oliveira (2), T.V. França, J.P. Wang |
| STC G, 57/1/2008, P.329 |
| Keywords: Vibration, Wheel Wear, Grinding |
|
Abstract : The aim of this work is to study the wheel/workpiece dynamic interactions in high speed grinding using vitrified CBN wheel and difficult-to-grind work materials. This problem is typical in the grinding of engine valve heads. The influence of tangential force per abrasive grain was investigated as an important control variable for the determination of G ratio. Experiments were carried out to observe the influence of vibrations in the wheel wear. The measurements of acoustic emission and vibration signals helped in identifying the correlation between the dynamic interactions (produced by forced random excitation) and the wheel wear. The wheel regenerative chatter phenomenon was observed by using the wheel mapping technique. |
| Simulation of the Local Kinematics in Rotational Grinding |
| E.Ahearne, G.Byrne (1) |
| STC G, 57/1/2008, P.333 |
| Keywords: Grinding, Simulation, Rotational Grinding |
|
Abstract : The rotational grinding process enables production of substrates for the semiconductor industry by a singular capacity to meet planarity and total thickness variation (TTV) requirements. However, the simple configuration is characterised by varying local kinematics. An upper-bound simulation of the meso-scale engagement kinematics has been developed with analysis algorithms that provide estimates of local kinematical parameters. These have been correlated with local measurements for typical brittle-mode microgrinding parameters including measurements of the local normal force. The results generally correlated for surface roughness but not for local normal force where 'equilibration' was attributed to system local and bending stiffness components. |
| Ultra-Precision Polishing of Electroless Nickel Molding Dies for Shorter Wavelength Applications |
| Y. Namba, T. Shimomura, A. Fushiki, A. Beaucamp, I. Inasaki (1), H. Kunieda, Y. Ogasaka, K. Yamashit |
| STC G, 57/1/2008, P.337 |
| Keywords: Optics, Polishing, Molding die |
|
Abstract : Electroless nickel is one of the best materials for making optical molding dies, because of its machinability with both single-point diamond turning and polishing, as well as its suitable hardness and durability. This paper deals with the ultra-precision polishing of aspheric molding dies for next generation hard X-ray telescope mirrors, which require a super smooth surface with a roughness below 0.3 nm rms. The material was machined using various methods, and a surface roughness of 0.23 nm rms was obtained on aspheric molding dies of 300 mm in diameter. A surface roughness of 0.16 nm rms was achieved on Platinum/Carbon multilayer mirrors, replicated from plano dies. |
| Nano-scale Scratching in Chemical-Mechanical Polishing |
| N. Saka, T. Eusner, J.-H. Chun (1) |
| STC G, 57/1/2008, P.341 |
| Keywords: Defect, Polishing, Semiconductor |
|
Abstract : During chemical-mechanical polishing (CMP) in the fabrication of advanced semiconductor devices, undesirable nano-scale scratches are produced, especially in the presence of low-k dielectrics. In this paper, the lower- and upper-bound loads for scratching are estimated by contact mechanics models and are validated by AFM experiments. Additionally, the width and depth of scratches are related to such process parameters as: particle size, abrasive volume fraction, mechanical and geometric properties of the pad and surface coatings, and polishing pressure. The upper-limit for scratch width is found to be a function of the particle size and the hardnesses of the coatings and the pad. In Cu CMP this limit is about one-fifth of the abrasive diameter. |
| Dressing Process Model for Vitrified Bonded Grinding Wheels |
| B. Linke / F. Klocke (1) |
| STC G, 57/1/2008, P.345 |
| Keywords: Grinding wheel, Dressing, Process model |
|
Abstract : A holistic dressing process model for vitrified bonded grinding wheels was designed. It regards the dressing process as a tribological system subjected to a complex load collective. The intensive analysis of the input variables and their impact on the system function led to new knowledge about the acting mechanisms. The model enables a qualitative prognosis of the grinding wheel topography, the dressing forces and the thermal dressing process load. |
| Form Crush Dressing of Diamond Grinding Wheels |
| J. M. Derkx, A.M. Hoogstrate, J.J. Saurwalt, B. Karpuschewski (1) |
| STC G, 57/1/2008, P.349 |
| Keywords: Grinding, Dressing, Diamond wheel |
|
Abstract : Form crush dressing is a method to profile diamond grinding wheels. Especially for complex profiles with intricate details and high accuracy an improved form crush profiling system has been developed. The system consists of a hydrostatically supported form crushing disc embedded in a swiveling axis. Form disc wear, which forms a major bottleneck in reaching high accuracy, has been minimized through the development of an advanced wheel synchronization control strategy. Various vitrified grinding wheels and a crushable metal bonded wheel have been tested to show the general applicability of the method to grinding wheels with brittle bond systems. |
| Simulation for Optimizing Grain Pattern on Engineered Grinding Tools |
| F.W. Pinto, G.E. Vargas, K. Wegener (3) / W. Knapp (1) |
| STC G, 57/1/2008, P.353 |
| Keywords: Grinding, Simulation, Wear |
|
Abstract : Engineered Grinding Tools (EGT) are characterized by a predetermined and controlled arrangement of the abrasive grains. The distribution of the abrasive grains can be used to enhance the grinding process by improving space for coolant supply and for chip removal. This is especially interesting for grinding operations with high specific material removal rates. A numerical method was developed to optimize the grain pattern on EGT. This method consists of a stochastic tool model, a kinematic process model, a material removal model and a grain wear model. The tool model comprehends the relevant geometric properties of the abrasive layer. The material removal model is based on the assumption of a kinematic-geometrical cutting condition. The wear model is based on a grain load limit and the grains’ load is assumed to be proportional to its cutting area. Once the cutting area of one grain exceeds the limit value, wear takes place. The model validation is presented comparing the wear behavior of EGT and workpiece roughness achieved with numerical and experimental methods. |
| High-Performance Dry Grinding using a Grinding Wheel with Defined Grain Pattern |
| J.C. Aurich (2), P. Herzenstiel, H. Sudermann, T. Magg |
| STC G, 57/1/2008, P.357 |
| Keywords: Grinding, Tool, Dry machining |
|
Abstract : This paper presents the potential of a superabrasive electroplated grinding wheel with a defined grain pattern for dry surface grinding operations. The grinding wheel’s grain pattern is developed by kinematic simulation with special focus on the undeformed chip thickness. Current experimental investigations of dry grinding operations of hardened heat-treated steel are carried out with a material removal rate of Q’w = 70 mm³/mms. The measured grinding forces, workpiece temperatures, as well as workpiece surface quality and workpiece integrity are compared to wet grinding and a standard superabrasive electroplated grinding wheel as a reference process. |
| Optimisation of Fluid Application in Grinding |
| M.N. Morgan, A.R. Jackson, H. Wu, V. Baines-Jones, A. Batako, W.B. Rowe (1) |
| STC G, 57/1/2008, P.363 |
| Keywords: Grinding, Coolant, Fluid delivery |
|
Abstract : This paper addresses the quantity of fluid required for grinding and the method of application. Results from this research suggest that supply flowrate needs to be 4 times the achievable ‘useful’ flowrate. Extra flowrate is wasted. It is shown that jet velocity and jet flowrate can be separately specified. Improved system design allows ‘actual’ useful flowrate to approach ‘achievable’ useful flowrate. Achievable useful flowrate depends on wheel porosity and wheel speed whereas actual useful flowrate depends on nozzle position, design, flowrate and velocity. Experimental methods are complemented by computational fluid dynamics (CFD) simulations. |
| A study of the Convection Heat Transfer Coefficients of Grinding Fluids |
| T. Jin, D.J. Stephenson (1) |
| STC G, 57/1/2008, P.367 |
| Keywords: Modelling, Grinding, Fluid |
|
Abstract : By using hydrodynamic and thermal modelling, the variation of the convection heat transfer coefficient (CHTC) of the process fluids within the grinding zone has been investigated. Experimental measurements of CHTC for different grinding fluids have been undertaken and show that the CHTC depends on the grinding wheel speed and the fluid film thickness within the contact zone. The film thickness is determined by grinding wheel speed, porosity, grain size, fluid type, flow rate and nozzle size. The CHTC values are compared for a wide range of grinding regimes, including HEDG, creep feed and finish grinding. |
STC M |
| Identification of Dynamic Cutting Force Coefficients and Chatter Stability with Process Damping |
| Y. Altintas (1), M. Eynian, H. Onozuka |
| STC M, 57/1/2008, P.371 |
| Keywords: Chatter, Cutting, Damping |
|
Abstract : This paper presents a cutting force model which has three dynamic cutting force coefficients related to regenerative chip thickness, velocity and acceleration terms, respectively. The dynamic cutting force coefficients are identified from controlled orthogonal cutting tests with a fast tool servo oscillated at the desired frequency to vary the phase between inner and outer modulations. It is shown that the process damping coefficient increases as the tool is worn, which increases the chatter stability limit in cutting. The chatter stability of the dynamic cutting process is solved using Nyquist law, and compared favourably against experimental results at low cutting speeds. |
| The Effect of Tool Vibrations on the Flank Surface Created by Peripheral Milling |
| T. Surmann, D. Biermann / H. Bley (1) |
| STC M, 57/1/2008, P.375 |
| Keywords: End milling, Modeling, Surface |
|
Abstract : Tool vibrations have a significant influence on the surface quality with respect to surface location error and roughness. Even chatter-free milling processes can produce a high surface location error since chatter-free does not necessarily mean vibration-free. This article describes a geometric model for predicting the surface formation resulting from peripheral milling processes when tool vibrations are present. This model enables one to predict and minimize the roughness and location error of the flank surface. Comparisons between simulations and experiments show the effectiveness of this modeling approach. An important result of this research is that it has shown that milling at a stability maximum does not generally yield the best surface quality. |
| Stability of Milling Processes with Continuous Spindle Speed Variation: Analysis in the Frequency and Time Domains, and Experimental Correlation |
| M. Zatarain (2), I. Bediaga, J. Munoa, R. Lizarralde (3) |
| STC M, 57/1/2008, P.379 |
| Keywords: Chatter, Milling, Speed Variation |
|
Abstract : Up to now, the theory for analysis of continuous spindle speed variation in milling processes was developed for sinusoidal variation only, and for average tooth passing frequency an exact multiple of speed variation frequency. This paper presents the general theory for analysis in the frequency domain and for any speed variation strategy. Results are compared with those obtained by semidiscretization and time integration, as well as with those obtained by experiments. The discrepancies of the results obtained by the different approaches are discussed, and the analysis of the evolution of the stability along the speed variation period is proposed. |
| Influence of the Ploughing Effect on the Dynamic Behaviour of the Self Vibratory Drilling Head |
| H. Paris, D. Brissaud (1), A. Gouskov, N. Guibert, J. Rech |
| STC M, 57/1/2008, P.385 |
| Keywords: Model, Drilling, Ploughing |
|
Abstract : The vibratory drilling process enables the chip to be split into small elements thanks to axial vibrations of the drill self-maintained by the cutting energy. The vibrations should remain stable when machining, and damping be removed or very limited — particularly the ploughing force induced by the chisel edge and the flank face. To predict the behaviour of the self vibratory drilling head, a new ploughing model has been developed. In this model, the interaction of the tool flank face with the machined material can be perceived as a virtual cutting edge that produces an additional thrust force and an additional removal of material. This model improves the cutting force models and is integrated into a numerical vibratory drilling simulator. The model shows a good correlation with experimental results. |
| Injection Molding Process Monitoring Using a Self-Energized Dual-Parameter Sensor |
| R.X. Gao, Z. Fan, D.O. Kazmer / S. Malkin (1) |
| STC M, 57/1/2008, P.389 |
| Keywords: Sensor, Injection, Molding |
|
Abstract : On-line monitoring of polymer melt state is critical to ensuring part quality in injection molding. This paper presents a novel, dual-parameter sensing method for simultaneous measurement of pressure and temperature variations within the mold cavity through a modulator circuit. Pressure variation during the molding cycle, which is proportional to the electrical charge output of a piezoceremic stack, is discretized into acoustic pulses that are subsequently frequency-modulated by a temperature-sensitive oscillator. The ability to measure two parameters using one sensor package without batteries and cables for data transmission provides a new platform for monitoring injection molding processes. |
| Adaptive Spindle Support for Improving Machining Operations |
| W.-G. Drossel (3), V. Wittstock / R. Neugebauer (1) |
| STC M, 57/1/2008, P.395 |
| Keywords: Adaptronic Design, Spindle Support, Piezo-electric |
|
Abstract : The Adaptive Spindle is a component, that allows additional fine positioning during machining operations by using a sub-kinematic system. The motor spindle is held by a piezo-based hexapod-kinematic. The article presents the different aspects of the design of an adaptronic component. With consideration of these aspects the work space of the end-effector were calculated. The characteristic values of the piezoceramic actuators, stroke and blocking force, were transformed to the structure of the active component by using design factors. The active system was validated in a special test bench. The potential and limits also for further applications are finally discussed. |
| Complex Form Machining with Axis Drive Predictive Control |
| D. Dumur (1), M. Susanu, M. Aubourg |
| STC M, 57/1/2008, P.399 |
| Keywords: Numerical control, Machine Tool, Machining |
|
Abstract : The paper proposes implementation of predictive control strategies on an industrial machining centre dedicated to high speed machining, realized within the framework of a CETIM study. Modelling, parameters identification and performances of the robustified axes drive polynomial controllers are first validated within a virtual machine-tool environment. Implementation is then achieved on the AXELOR 20SL machining centre, equipped with a Power Automation CNC. The computation of the controllers is carried out through the concept of compile cycles for real time scheduling. Results obtained with predictive control when machining a complex workpiece are finally compared to those achieved with the classical CNC control architecture. |
| Accurate Motion Control of an XY Linear-Motor Drive for High-Speed Milling using Friction Model Feedforward and Cutting Force Estimation |
| Z. Jamaludin, H. Van Brussel (1), G. Pipeleers, J. Swevers |
| STC M, 57/1/2008, P.403 |
| Keywords: Accuracy, Control, Motion |
|
Abstract : Accurate motion control is essential for machine tools. Both friction forces and cutting forces contribute to position and contour tracking errors. This paper presents a feedforward friction force compensation based on the Generalized Maxwell-slip friction model that describes friction behaviour both in pre-sliding and sliding regime. An inverse-model based disturbance observer is added to further improve the friction compensation. This disturbance observer is able to only partly reduce the effects of cutting forces. An almost complete elimination of these effects is obtained by adding a repetitive controller. Experimental validations of these approaches on a linear-motor based xy table are presented. |
| A Heuristic Feedrate Optimization Strategy for NURBS Toolpaths |
| K. Erkorkmaz (2), M. Heng |
| STC M, 57/1/2008, P.407 |
| Keywords: Spline, Feed, Optimization |
|
Abstract : This paper presents a new and computationally efficient feedrate optimization strategy for spline toolpaths. The technique combines analytically derived compatibility equations with a heuristic search method, which helps generate feed profiles with reduced cycle time while adhering to axis velocity, acceleration, torque, and jerk constraints. Feed modulation is realized using the S-curve function, which allows optimized feed profiles to be implemented on existing CNC’s. The proposed strategy yields shorter cycle time compared to the frequently used worst-case curvature approach, and converges faster than more elaborate gradient-based optimization techniques. The effectiveness of the new strategy is demonstrated in contour machining experiments. |
| Development of 45 Degrees Tilted On-Machine Measuring System for Small Optical Parts |
| H. Suzuki, T. Onishi, T. Moriwaki (1), M. Fukuta, J. Sugawara |
| STC M, 57/1/2008, P.411 |
| Keywords: Measuring instrument, Ultraprecision, Mold |
|
Abstract : A new contact type on-machine measuring system is developed in order to measure aspherical optical parts with steep surface angle for high numerical aperture (NA). A ceramic air slider made of SIALON is adopted for the measurment probe because of its low thermal expansion coefficient, high rigidity and light weight. A high accuracy glass scale is employed to reduce the thermal drift of the displacement gauge. The air slider or the measuring probe is tilted for 45 degrees against the aspherical workpiece axis, and the probe is scanned over the workpiece surface, so as to keep the contact angle between the probe axis and the contact surface constant in order to reduce the change in the probe friction force. |
| Development of Ultra-precision Machining System with Unique Wire EDM Tool Fabrication System for Micro/Nano Machining |
| X. Cheng, K. Nakamoto, M. Sugai, S. Matsumoto, Z.G. Wang, K. Yamazaki (1) |
| STC M, 57/1/2008, P.415 |
| Keywords: Ultra-precision machine tool, Wire EDM, Ductile mode micromachining |
|
Abstract : Aiming at quality machining of very hard materials with nanometer level surface quality and 0.1 µm dimensional accuracy, an ultra-precision machining system has been developed. The machine has feed axes accompanied by the counter motion mechanism driven at the center of gravity to eliminate the vibration caused by high acceleration/deceleration. A custom tool fabrication system consists of a six-axis wire EDM machine and dedicated custom tool CAM system. High quality machining of sophisticated 3-D products made of tungsten carbide has successfully been demonstrated on the developed machine tool with custom-made PCD cutters fabricated by the tool fabrication system |
| Design of a Planar Type High-Speed Parallel Mechanism Positioning Platform with the Capability of 180-degree Orientation |
| W. In, S. Lee, J.I. Jeong, J. Kim (2) |
| STC M, 57/1/2008, P.421 |
| Keywords: Positioning system, Parallel mechanism, Redundant actuation |
|
Abstract : This paper presents a planar type redundantly actuated parallel mechanism, for which the maximum velocity is 150 m/min with an acceleration of 2g. The velocity is one of the highest for positioning platforms with the stroke around 500 mm. Since it has three degrees of freedom and four actuators, it has basically one redundancy that is essential to achieve high-degree dexterous motions. This paper deals with the theoretical results of kinematic and dynamic analysis of the mechanism, control issues for maintaining high velocity and positioning accuracy, redundancy control issue, and finally, the experimental results obtained from the prototype. |
| Measurement Pose Selection and Calibration Forecast for Manipulators with Complex Kinematic Structures |
| A. Verl, T. Boye, A. Pott / G. Pritschow (1) |
| STC M, 57/1/2008, P.425 |
| Keywords: Kinematics, Calibration, Parallel Manipulator |
|
Abstract : Kinematic calibration of complex manipulators comprises the choice of measurement poses, i.e. the position and the orientation of the end-effector in the workspace of the manipulator. The calibration result expressed by the resulting condition of the identification matrix depends essentially on the chosen measurement poses. In this article a fast and effective algorithm is proposed to find a well conditioned set of measurement poses within a fixed set of pose configurations. Further on, an interrelationship between the number of measurement poses and the standard deviation of the TCP (Tool Center Point) is presented. The practical usefulness of the algorithm is exemplified by means of a parallel kinematic machine. |
STC O |
| Dynamic Multi-objective Optimisation for Machining Gradient Materials |
| R. Roy (2), J. Mehnen |
| STC O, 57/1/2008, P.429 |
| Keywords: Optimisation, Genetic, Computer Aided Manufacturing (CAM) |
|
Abstract : Efficient machining of material with continuously varying properties, so called gradient material, needs advanced planning of cutting parameters; this is a dynamic optimisation problem. Additionally the manufacturing has to satisfy several constraints in parallel. The parameters are optimised using a new predictive multi-objective optimisation approach based on Genetic Algorithms. The algorithm adapts online to the dynamically varying hardness properties of the material. A model based detailed case study is presented where the optimisation identifies good parameter sets for the machining. The solutions are finally selected based on a desirability function and heuristics. |
| Development of Remote Monitoring and Maintenance System for Machine Tools |
| M. Mori (2), M. Fujishima (3), M. Komatsu, Bingyan Zhao, Yadong Liu |
| STC O, 57/1/2008, P.433 |
| Keywords: Maintenance, Monitoring, Network |
|
Abstract : This paper introduces a system for machine tool manufacturers to monitor and maintain their customers' machine tools remotely. Two communication options are discussed to physically connect thousands of machine tools worldwide to the manufacturer's server. XML file format is used to send the machine tool status. To process and store huge amount of incoming data, a parallel processing strategy is applied to improve the conventional sequential way. With the established network and collected data, applications such as remote maintenance, monitoring and preventive maintenance are presented. The developed system can reduce customers' machine downtime and the manufacturer's service cost. |
| A Service Evaluation Method using Mathematical Methodologies |
| Y. Shimomura, T. Hara, T. Arai (1) |
| STC O, 57/1/2008, P.437 |
| Keywords: CAD, Simulation, Service Engineering |
|
Abstract : A method for evaluating service solutions is proposed. First, a fundamental definition of a service and its elements are given to describe the service. Quality Function Deployment (QFD), used widely in product design, is then employed. This method makes it possible to realize evaluating effects of a service on its receiver. Mathematical methods are introduced to differentiate functions and structures. Then, the proposed method is applied to evaluate a clothes-washing service in order to verify its effectiveness. The results indicate that a specific function is the most important among multistage structure of the target service. |
| A Stochastic Linear Programming Approach for Service Parts Optimization |
| P.M. Lonardo (1), D. Anghinolfi, M. Paolucci, F. Tonelli |
| STC O, 57/1/2008, P.441 |
| Keywords: Optimization, Cost, Service Parts Management |
|
Abstract : Service Parts Stock Management is a part of the service process to ensure that right spare parts are in the warehouse at the right place and time, with respect to a customer demand. Customer satisfaction can be measured through the First Fill Rate Value (FFRV). The FFRV optimization is an inventory planning problem, which can be formalised through a stochastic linear programming problem and evaluated for different spare parts or sets of them, considering production and cost constraints. In this paper the problem and the details of the proposed approach will be discussed and assessed through some experimental data. |
| Complexity-Based Modeling of Reconfigurable Collaborations in Production Industry |
| G. Schuh (2), L. Monostori (1), B.Cs. Csaji, S. Döring |
| STC O, 57/1/2008, P.445 |
| Keywords: Modeling, Production, Complexity |
|
Abstract : Engaging in collaborations and managing relationships within the same have become a major concern for managers in industrial companies. However, the direct transfers of current management approaches to complex networked enterprises working in highly dynamic environments fail regularly, as they lack problem-oriented interdisciplinary inferences. The cooperative EU funded project, COLL-PLEXITY, - Collaborations as Complex Systems - shifts from existing approaches to collaboration. It targets the interdisciplinary devel-opment of a generic model of complexity as the basis for a problem-to-system match framework for collabo-rative systems in the production industry. The paper explains the scientific approach to this model and its expected applicability in production industry. |
| Supply chain modeling and control for producing highly customized products |
| D. Mourtzis (2), N. Papakostas, S. Makris, V. Xanthakis, G. Chryssolouris (1) |
| STC O, 57/1/2008, P.451 |
| Keywords: Production; Modeling; Management Information Systems (MIS) |
|
Abstract : This paper discusses a method of dynamically querying supply chain partners to provide real time or near real time information regarding the availability of parts required for the production of highly customizable products. This method utilizes Internet based communication and real time information from RFID sensors. The feasibility of this approach is demonstrated with its implementation in a typical automotive case. |
| A Coordination Mechanism for Rolling Horizon Planning in Supply Networks |
| J. Vancza (2), P. Egri, L. Monostori (1) |
| STC O, 57/1/2008, P.455 |
| Keywords: Production, Co-operative, Planning |
|
Abstract : We model planning in a supply network as a distributed effort for matching future demand with supply on a rolling horizon, by relying on asymmetric and in part uncertain information. For achieving high service level and low overall costs throughout the network there is a need of managing the intentions and interactions of the partners. We present a novel coordination mechanism where sharing information truthfully and planning local production optimally serve both system-wide and individual objectives. The work is nested in practice: application examples are taken from the production of customized mass products. |
| The Behaviour of Learning Production Control |
| B. Scholz-Reiter (2), T. Hamann |
| STC O, 57/1/2008, P.459 |
| Keywords: Production; Control; Neural Network |
|
Abstract : The increasing diversity of products and the fluctuation in customer demand require new strategies of de-central production control. This particularly concerns versatile and customer order oriented shop floor pro-duction. The introduced control strategy uses, on one hand, neural networks to control the inventories on each work system. On the other hand, the simulated annealing approach ascertains adequate target invento-ries. The effectiveness of this continuously learning production control strategy is verified by a theoretical model and one practical case. The control quality improves successively and the system can react according to changing conditions. |
| Dynamic Modeling of Production Networks of Autonomous Work Systems |
| N.A. Duffie (1), D. Roy, L. Shi |
| STC O, 57/1/2008, P.463 |
| Keywords: Production, Control, Dynamic Model |
|
Abstract : In this paper, a dynamic model is presented for production networks with a potentially large number of autonomous work systems, each having local capacity control. The model allows fundamental dynamic properties to be predicted using control-theoretic methods, together with the response of variables such as work-in-progress and lead-time for the network and its individual work systems. This is illustrated using industrial data. The behavior of one of the work systems in this network is analyzed further, and the results are compared with results obtained using a discrete event simulation model. |
| Modelling Evolution in Manufacturing: A Biological Analogy |
| H.A. ElMaraghy (1), T.N. AlGeddawy, A.A. Azab |
| STC O, 57/1/2008, P.467 |
| Keywords: Product, Manufacturing, Cladistics |
|
Abstract : Manufacturing systems evolved over time due to products evolution, changes in market demands, technological advances and emergence of new innovations and designs. All terminology used in conjunction with this evolution to date are synonymous with change. A new classification of the various terms used in the context of manufacturing systems evolution and their definitions, inspired by the evolution manifested in nature, are introduced. An innovative mapping between the evolution of manufactured products and biological evolution is proposed where Cladistics are used to track such evolution. A typical industrial example is used for illustration. The significance and applications of this approach are discussed. The obtained results provide a promising foundation for future research in products and manufacturing systems evolution and co-evolution. |
| Modelling of Value Creation Based on Emergent Synthesis |
| K. Ueda (1), T. Kito, T. Takenaka |
| STC O, 57/1/2008, P.473 |
| Keywords: Emergent synthesis, Service, Value creation |
|
Abstract : With increasing networking and globalization of the market, it becomes increasingly difficult to understand value in production of goods and services. This paper presents a new methodology for modelling value creation based on the concept of Emergent Synthesis. In consideration of interaction among producers, customers, and the environment, the methodology classifies value creation into three models: Providing Value, Adaptive Value, and Co-creative Value. This paper presents multi-agent system simulations of service market to examine the validity of the proposed models, with discussion of the diffusion of new products/services in a society. |
| Large Volume Process Models: A Framework for Integrating Measurement with Assembly |
| P.G. Maropoulos (1), Y. Guo, J. Jamshidi, B. Cai |
| STC O, 57/1/2008, P.477 |
| Keywords: Metrology Process Model, Measurement Planning, Computer Automated Process Planning (CAPP) |
|
Abstract : This paper describes a generic methodology dealing with the theoretical definition of metrology process models and their systematic integration with design evaluation and assembly planning. The research resulted in the specification of a novel, theoretical framework for the specification and generation of metrology process models, especially focusing on large volume, frameless metrology that is suitable for the verification of large and complex products. The process modelling framework has four generic sections that support early design evaluation, assembly process interface, set-up and deployment, and verification data management. Initial testing results, using aerospace products, demonstrated the effectiveness of the process modelling methods. |
| Reduction of Capital Tie Up for Assembly Processes |
| P. Nyhuis (2), M. Schmidt, F.S. Wriggers |
| STC O, 57/1/2008, P.481 |
| Keywords: Logistics; Modelling; Logistic Operating Curves Theory |
|
Abstract : To be efficient companies have to consider the trade off between high service levels and low capital tie up. This is particularly important in stores adjacent to assembly processes. Problems occurring in these stores impact customer satisfaction directly and the parts are stored on a high value added level further increasing the clash of targets. A method for positioning stores in compliance with both targets is proposed. Advancing the Logistic Stock Analysis this new method is especially tailored to consider unit service levels and thus to minimize capital tie up with regard to customer service levels for the first time. |
| Shaping inter-firm Collaboration in New Product Development in the Automobile industry: A trade-off between a Transaction and Relational Based approach |
| E. Mazzola, G. Perrone (2), S. Noto La Diega (1) |
| STC O, 57/1/2008, P.485 |
| Keywords: Product development, Co-operative Production, Co-operative Concurrent Engineering |
|
Abstract : Shaping collaboration in the New Product Development (NPD) has always been a very difficult task, especially in complex industries like the automobile one. This complexity is particularly true during the engineering phase of the NPD process, where different complex systems are to be designed in a collaborative way. Basically, two kind of approaches have been observed in the literature and industry: one is more related to market transactions, specifically the west car-company style, the other is more relational based, as in the Japanese car company style. Now, the increasing globalisation of the industry asks for a merge of the two approaches; indeed, the increasing use of standard components push towards a market outsourcing, while the need of product customisation and the increasing technology complexity push towards long term alliances and partnerships; then, several companies face the problem of how designing good collaboration solutions in several phases of the NPD process. This paper offers a methodological solution to this problem by searching a trade-off between market and relational approaches and by offering to the Original Equipment Manufacturer (OEM) a decision support for shaping well fitting inter-firm relationship. |
STC P |
| Study of a Micro Roughness Probe with Ultrasonic Sensor |
| K. Hidaka (3), A. Saito, S. Koga / P.H.J. Schellekens (1) |
| STC P, 57/1/2008, P.489 |
| Keywords: Ultrasonic, Sensor, Roughness, |
|
Abstract : This paper presents a micro-roughness measuring probe which involves an ultrasonic vibration sensor in a longitudinal tapping mode. This sensor is controlled by a measuring force control system. The combination of a fine and coarse driving mechanism realizes non-destructive, accurate and high speed measurement. The measuring force is 1 µN to 1 mN with 1 kHz maximum dynamic response in the vertical axis. A mechanical structure, the characteristics of it and an evaluation method of the measuring force are described in the paper. Several results, for instance the surface damage after tracing and micro-roughness measurement, are shown. |
| Development of the nano-probe system based on the laser trapping technique |
| M. Michihata, Y.Takaya (2), T. Hayashi |
| STC P, 57/1/2008, P.493 |
| Keywords: Coordinate Measuring Machine (CMM), Probe, Microstructure |
|
Abstract : A nano-coordinate measuring machine (CMM) has been developed to achieve a measuring accuracy of 50 nm and a measuring volume of 10 mm3. To meet these stringent requirements, a laser trapping probe is employed as a nano-sensing probe. This paper describes the development of the nano-CMM system with a laser trapping probe and describes the performance of the probe via an assessment of the flatness and microsphere. It is observed that the laser trapping probe can sense three-dimensional objects with a repeatability of 32 nm. Using the nano-CMM, the measurement uncertainty is estimated to be 250 nm (k = 2). |
| Calibration Artefact for the Micro Scale with High Aspect Ratio: the Fiber Gauge |
| F. Marinello, E. Savio (2), S. Carmignato, L. De Chiffre (1) |
| STC P, 57/1/2008, P.497 |
| Keywords: Calibration, Miniaturisation, Fiber |
|
Abstract : The paper presents a new concept of micro artefact, the Fiber Gauge, consisting on a set of optical fibers sticking out from a flat surface. The fibers are arranged as a regular array of different height cylinders, with aspect-ratios up to 20:1. The artefact is produced taking advantage of optical fibers manufacturing technology, featuring relatively high geometrical accuracy, combined with very good mechanical properties. The Fiber Gauge can be applied to calibration of most contact or non-contact instruments for characterization of surface topographies and 3D micro geometries, such as micro- or nano-CMMs, optical instruments, etc. Different designs and dimensions allow for realization of structures that can be adapted to various instruments calibration needs. Development, analysis and application of prototype artefacts are reported. |
| A method for the automated positioning and alignment of fibre-reinforced plastic structures based on machine vision |
| R. Schmitt, T. Pfeifer (1), C. Mersmann, A. Orth |
| STC P, 57/1/2008, P.501 |
| Keywords: Composite, In-process measurement, Visual inspection, Fiber |
|
Abstract : The application of fibre-reinforced plastics is important in many engineering areas. This work describes a method for the automated positioning and alignment of fibre-reinforced plastic structures for composite materials based on machine vision technology. The developed method applies data fusion from two sensor principles. The first one is an image processing sensor for the robust detection of the local fibre orientation and the second one is a light section sensor for the determination of the contour position of textile preforms. The developed method can measure different quality criteria of preform structures and was evaluated under industrial conditions through a prototype. |
| Optical Inspection of Complex Patterns of Microelectronics Products |
| J. You, S.-W. Kim (2) |
| STC P, 57/1/2008, P.505 |
| Keywords: Optical, Inspection, Measurement |
|
Abstract : Low-coherence interferometry is exploited for the high speed 3-D inspection of microelectronics products comprised of composite features of different surface characteristics. Emphasis is on configuring an optimum optical hardware design to deal with large rough objects measuring up to a few hundreds micrometers in height. The inspection speed is improved by extending the lateral field-of-view of a single measurement to cover extensive ranges up to a few tens millimetres. Thin films are also gauged by analyzing the spectrally nonlinear variation of interference signals. The overall performance is demonstrated by measuring metal bumps fabricated on film-coated substrates. |
| Uncertainty evaluation for measurements of peak-to-valley surface form errors |
| C.J. Evans (1) |
| STC P, 57/1/2008, P.509 |
| Keywords: Metrology, Uncertainty, Spatially varying errors |
|
Abstract : The peak-to-valley deviation of a surface from its specified form is a widely used, conceptually simple surface specification. Evaluating the uncertainty in PV is not so simple. In the presence of noise, the measured PV is always too large. This paper shows an approach to correcting that bias. A number of error sources in interferometric testing of surfaces result in errors that have spatial variations across the aperture under test. Uncertainty in the correction of these errors, for example, leads to uncertainties that vary with position. This paper offers a procedure for evaluating the uncertainty in PV in this case. |
| Geometrical Checking by Virtual Gauge, Including Measurement Uncertainties |
| J. Mailhe, J.M. Linares, J.M. Sprauel, p. Bourdet (1) |
| STC P, 57/1/2008, P.513 |
| Keywords: Coordinate Measuring Machine (CMM), Uncertainty, Geometric Modeling |
|
Abstract : For the most part, metrology software is currently based on the calculation of distances or angles between geometrical elements. This kind of method implies series of geometrical constructions which are amplifying measurement uncertainties. Usually, the estimation of error bars is then done after the geometrical verifica-tion. Hence, uncertainties are not directly taken into account during the checking process. To avoid these im-pediments, a new checking method, based on virtual gauges, is proposed in this paper. Based on Gram ma-trix, virtual gauges permit to perform checking without any intermediate geometrical construction. Moreover, thanks to a statistical description of the specified surface, the measurement uncertainties are thus directly taken into account during the conformance test process. An example of application is presented to demon-strate the relevance of this approach. |
| Tschebyscheff Approximation for the Calculation of Maximum Inscribed/Minimum Circumscribed Geometry Elements and Form Deviations |
| G. Goch (1), K. Lübke |
| STC P, 57/1/2008, P.517 |
| Keywords: Form inspection, Algorithm, Minimum circumscribed element |
|
Abstract : The calculation of dimensional deviations is mandatory for the quality inspection of geometry elements. This paper describes a method for the approximation of geometry elements by Gauss/Tschebyscheff algorithms. Moreover, the Tschebyscheff algorithm is the correct approach to determine correctly standardized form tolerances like roundness, flatness or cylindricity deviations. A modification of the conventional Tschebyscheff algorithm leads to maximum inscribed and minimum circumscribed elements. The presented Tschebyscheff algorithms are applied to circles, cylinders and other geometry elements and verified by using test profiles. |
| Statistical Quality Control in Micro Manufacturing through multivariate µ-EWMA Chart |
| J. Fleischer (2), G. Lanza, M. Schlipf |
| STC P, 57/1/2008, P.521 |
| Keywords: Quality Assurance, Microstructure, Statistical Process Control |
|
Abstract : Micro manufacturing processes are characterized by high process variability and an increased significance of measurement uncertainty in relation to tight tolerance specifications. Therefore, an approach that separates the superposition of measurement and manufacturing variation is demanded. A novel design for a quality control chart that makes it possible to monitor, control and extract measurement variation from manufacturing variation is proposed. Thus, a definite cause diagnosis on the approval or rejection of micro components due to errors either in the measurement or in the manufacturing process is possible. The proposed multivariate µ-EWMA chart which is based on weighting each measurement data with its current measurement variation is discussed and benchmarked with traditional control charts. |
| Large Scale Space Angle Measurement |
| G.X. Zhang (1), J.W. Yao, Z.R. Qiu, W.C. Hu. F.Z. Fang (2), X.H. Li |
| STC P, 57/1/2008, P.525 |
| Keywords: Measurement, Calibration, Angle |
|
Abstract : A method for measuring the angle of two elements separated at a large distance by using a common optical reference is proposed. A common light plane or several parallel light planes are projected on these elements. The angles between these elements and the projections of light planes are measured and thereafter the angle between these two elements is determined. A practical example of measuring the angle formed by two elements separated at a distance of 7 m is shown. Its calibration method is also discussed. |
| Systematic Evaluation of Calibration Methods |
| B. Bringmann, J.P. Besuchet, L. Rohr / T. Estler (1) |
| STC P, 57/1/2008, P.529 |
| Keywords: Calibration, Simulation, Uncertainty |
|
Abstract : Today for geometrically testing and calibrating machine tools, many different measuring devices are used. Generally it is only based on the experience of single employees which methods for calibration are applied. There is no quantifiable understanding of the correlation between measurement method, measurement uncertainty, machine tool build-up (axes arrangement) and quality and the resulting obtainable workpiece accuracy. In this paper a kinematic model of machine tools is used with which resulting deviations of workpieces can be simulated, thus giving a realistic impression of the geometric performance of a machine tool by considering all relevant influence factors. For a 5-axis machining center as an example it is quantified how improved calibration methods can reduce the resulting workpiece deviations significantly. With this knowledge, optimal calibration methods can be chosen and weak points in the machine tool design can be identified systematically. |
| Process Monitoring in Non-Circular Grinding with Optical Sensor |
| C.P. Keferstein, D. Honegger, H. Thurnherr, B. Gschwend / G. Levy (1) |
| STC P, 57/1/2008, P.533 |
| Keywords: In-process measurement; Optical; Grinding |
|
Abstract : Cylindrical grinding machines are increasingly used to produce workpieces with non-circular contours. This means that new demands are made on process-monitoring and in-process measurements due to these non-circular contours. A new optical sensor system was integrated into such a grinding machine; making it possible to take measurements for quality assurance, optimisation of the grinding process and reduction of setting-up and machining time. |
STC S |
| Scanning Positron Microscopy: Non-destructive Imaging of Plastic Deformation in the Micrometer Range |
| M. Haaks / L. Cronjäger (1) |
| STC S, 57/1/2008, P.537 |
| Keywords: Defect, Fatigue, Image |
|
Abstract : Positron annihilation spectroscopy (PAS) provides an extremely sensitivity for the detection of lattice defects from a concentration of 10-6 defects per atom. PAS is a versatile and non-destructive tool for the study of plasticity and fatigue in solid state materials. Scanning Positron Microscopy (SPM) expands the capabilities of PAS into the micron range. Recent results of defect imaging by SPM on plastically deformed and fatigued metals and semiconductors will be presented in this paper. A new method estimating the remaining useful life of fatigued components by employing the S parameter as a precursor for failure will be introduced. |
| Cold Surface Hardening |
| E. Brinksmeier (1), M. Garbrecht, D. Meyer |
| STC S, 57/1/2008, P.541 |
| Keywords: Surface, Hardening, Steel |
|
Abstract : Cold surface hardening merges the properties of specially heat treated high alloyed steels with structural changes induced by mechanical processes such as deep rolling. Compared to conventional transformation induced plasticity- (TRIP-) steels these materials show noticeably better machinability because the generated austenitic structure is stable enough to avoid transforming during cutting processes. As a result of the mechanical stresses applied by a deep rolling tool after machining, martensitic transformation occurs in the surface layer to a depth up to 0.5 - 0.6 mm. The advantages of this innovative approach include the elimination of thermal hardening and the combination of hardening and surface finishing in one step which is performed on the same machine tool. Less distortion and economical savings are further advantages of this new manufacturing technology. |
| Functionalization of Stainless Steel Surface Through Mirror-Quality Finish Grinding |
| H. Ohmori (2), K. Katahira, J. Komotori, M. Mizutani |
| STC S, 57/1/2008, P.545 |
| Keywords: Grinding, Finishing Process, Surface quality |
|
Abstract : In this study, a stainless steel mirror-finished surface obtained by a high-precision grinding process was investigated in detail using some advanced surface analyzing techniques. We found that the mirror-surface grinding process produced a stable oxide layer on the workpiece surface, and also that the abrasive elements of the grinding wheel penetrated and diffused into the substrate. Compared with surfaces that had been polished, surfaces that had been mirror-finished by grinding process exhibited superior surface properties including hardness, tribological and fatigue properties, corrosion and high-temperature oxidation resistances, and adhesive strength with coating films. In addition, varying the processing conditions offers the possibility of controlling the electrical potential characteristics and hydrophilicity of the surfaces. |
| TiO2 Coating on Metal and Polymer Substrates by Nano Particle Deposition System (NPDS) |
| D.M. Chun, M.H. Kim, J.C. Lee, S.H. Ahn / S.I. Oh (1) |
| STC S, 57/1/2008, P.551 |
| Keywords: Surface, Deposition, Nano manufacturing |
|
Abstract : TiO2 thin films have been widely used in corrosion protection, solar cells, self-cleaning surfaces, photocatalysis, capacitors etc. In this research, TiO2 thin films were deposited on metal substrates (stainless steel, Cu alloy, Al alloy) and polymer substrates (PET, PMMA) by nano particle deposition system (NPDS) at room temperature and low vacuum condition. Submicron size TiO2 powders were sprayed through the supersonic nozzle and deposited at high deposition rate without thermal damage on the substrates. Material properties such as hardness, modulus, chemical composition, adhesion and morphology were measured. The test results showed that the NPDS provides a good coating method of TiO2 material for applications requiring large surface areas. |
| Wavelets and their Applications for Surface Metrology |
| X. Jiang (2), P. Scott, D. Whitehouse (1) |
| STC S, 57/1/2008, P.555 |
| Keywords: Surface, Analysis, Wavelet |
|
Abstract : This paper presents three generations of wavelet representations that are designed for micro/nano scale surfaces. These wavelets include a basic biorthogonal wavelet (for the establishment of a surface filtering equation), an evolutionary lifting wavelet (for surface oriented frequency analysis, surface recognition and reconstruction with nano-scale accuracy), and a complex wavelet (for surface morphological feature extraction). The benefits of using these wavelets in the subject area will be demonstrated throughout as follows (1) their metrology properties: the linear phase, finite impulse filtering, simplicity and naturalness, shift-invariance and direction sensitivity; and (2) practical applications in surface measurement denoising, feature extraction for engineering and bioengineering surfaces. |
| Prediction of Scratch Generation in Chemical Mechanical Planarization |
| A. Chandra (2), P. Karra, A.F. Bastawros, R. Biswas, P.J. Sherman , S. Armini, D.A. Lucca (1) |
| STC S, 57/1/2008, P.559 |
| Keywords: Planarization, Agglomeration, Defectivity |
|
Abstract : A multi-scale model encompassing pad response and slurry behavior is developed to predict scratch propensity in a CMP process. The pad response delineates the interplay between the local particle level deformation and the cell level bending of the pad. The slurry agglomerates in the diffusion limited agglomeration (DLA) or reaction limited agglomeration (RLA) regime. Various nano-scale slurry properties significantly influence the spatial and temporal modulation of the material removal rate (MRR) and scratch generation characteristics. The model predictions are first validated against experimental observations. A parametric study is then undertaken. Such physically based models can be utilized to optimize slurry and pad designs to control the depth of generated scratches and their frequency of occurrence per unit area. |
| Nanoscale Surface Property Estimation Using Proper Orthogonal Decomposition in Atomic Force Microscopy |
| S.I. Lee, S.H. Hong, J.M. Lee (1) |
| STC S, 57/1/2008, P.563 |
| Keywords: Surface, Atomic force microscopy (AFM), Proper orthogonal decomposition (POD) |
|
Abstract : Atomic force microscopy (AFM) in a dynamic mode operation uses a resonating tip to measure the nanoscale surface topography and other properties. The dynamic response of the tip includes the complex tip-surface interactions due to the surface properties. We found that conventional tapping mode had a limitation in the accurate set-point control on soft and high adhesion surfaces. This study employed the proper orthogonal decomposition (POD) based AFM microcantilever characterization method to estimate the surface property with more reliable control. The POD extracted the dominant empirical modes of the AFM microcantilever during tapping and scanning on the surface. Also the corresponding eigenvalues represented the significance of the empirical modes and the characteristic features of the nanoscale surface property. This experimental approach can offer a new insight on the novel application of nanoscale surface property estimation in dynamic AFM applications. |
| Damage-Free Improvement of Thickness Uniformity of Quartz Crystal Wafer by Plasma Chemical Vaporization Machining |
| K. Yamamura, S. Shimada (1), Y. Mori |
| STC S, 57/1/2008, P.567 |
| Keywords: Etching, Single crystal, Wafer |
|
Abstract : The thickness uniformity of an quartz crystal wafer is an essential requirement for improving the productivity of a quartz resonator because it prevents frequency adjustment after dicing the wafer. In this paper, chemical finishing utilizing a localized atmospheric pressure plasma is proposed to correct the thickness deviation of a quartz crystal wafer. In this process, free figuring without mask patterning can be realized by the numerically controlled scanning of a localized removal area. The thickness uniformity of a commercially available quartz wafer is improved from 250 nm to 50 nm only by one correction without subsurface damage. |
| Evaluation of Bacteria Compatible Microporous Surfaces for Biofuel Cells |
| T. Moriuchi, K. Morishima, Y. Furukawa (1) |
| STC S, 57/1/2008, P.571 |
| Keywords: Surface, Microstructure, C-MEMS |
|
Abstract : Prototypes of photosynthetic-bacterium micro-biofuel cells have been developed in our laboratory, in which electrons are extracted from bacterial cells while they are in contact with an electrode. The material and shape of the electrode should be electroconductive and biocompatible with a low electrical resistance and a high-specific surface area, therefore, pyrolyzed carbon was fabricated either to a flat or porous surface electrode using carbon microelectromechanical systems (C-MEMS). The developed electrodes were applied in micro-biofuel cells, and the porous electrode showed a fourfold higher performance than the flat one. |
| Evaluation of Wear Resistance of AlSiTiN and AlSiCrN Nanocomposite Coatings for Cutting Tools |
| L. Settineri (2), M.G. Faga, G. Gautier, M. Perucca |
| STC S, 57/1/2008, P.575 |
| Keywords: Coating, Surface Analysis, Cutting Tool |
|
Abstract : Nanocomposite coatings, consisting of nanocrystalline AlTiN or AlCrN dispersed in a matrix of amorphous Si3N4 were deposited onto hard metal substrates via Cathodic Arc PVD. Coating thickness, adhesion properties and hardness have been measured. Wear resistance was measured via tribological tests and the main wear phenomena were studied using SEM-EDS. The coatings have then been functionally tested as cutting tool coatings for WC mills for high speed, dry milling operation on AISI M2, a difficult to cut die steel. Cutting performances and laboratory results have been discussed, together with wear mechanisms, in light of the comparison with commercial nitride-coated tools. |
| Optimisation of Composite Castings by Means of Neutron Measurements |
| U. Wasmuth, L. Meier, M. Hofmann, M. Mühlbauer, V. Stege , H. Hoffmann (2) |
| STC S, 57/1/2008, P.579 |
| Keywords: Residual Stress, Simulation, Neutron Diffraction |
|
Abstract : The composite casting process is mainly used to produce composite engine blocks with in-cast liners. Due to different thermal expansion of the casting material and the material of the insert residual stresses occur during solidification. These residual stresses can reduce fatigue strength and lead to distortions of the part. They can be minimised by constructive measures. Casting simulation is a suitable method to predict residual stresses and distortions and thus to optimise design of parts. To improve the accuracy of stress simulation composite castings were designed and characterised using conventional and modern test methods such as neutron tomography and neutron diffraction. Neutron diffraction enables to measure, non-destructively, stress distributions within the bulk of the specimen. The results are used to verify and optimise the residual stress simulation. In the end this enables an optimised construction of composite castings. |