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CIRP Annals Online sorted by Year and Volume




Absolute sustainability – challenges to Life Cycle Engineering
Michael Z. Hauschild (1), Sami Kara (1), Inge Ropke  
STC A,  69/2/2020,  P.533
Keywords: Lifecycle, Methodology, Absolute sustainability
Abstract : The global society faces huge challenges to meet the expanding needs of a growing population within the constraints posed by a climate crisis and a strongly accelerated loss of biodiversity. For sustainability, the total environmental impact of our activities must respect the planetary boundaries that define what is a safe operating space for our civilization. Engineering must change the current focus on ecoefficiency to a search for solutions that are effective in terms of operating within the share of the total pollution space that they can claim. Engineering for environmental sustainability must be life cycle engineering, and the paper positions it relative to the constraints given by the boundaries of the ecosystems, the targets of the United Nations’ sustainable development goals and the strategies for a circular economy. This top-down perspective is combined with a bottom-up perspective from the life cycle of the product and technology. For each stage of the life cycle, the contents of the toolbox for life cycle engineering are reviewed, and a perspective is given on how absolute environmental sustainability requirements can be incorporated in a target-driven life cycle engineering.


Broaching: cutting tools and machine tools for manufacturing high quality features in components
Pedro J. Arrazola (1), Joël Rech (2), Rachid M’Saoubi (1) Dragos Axinte (1)  
STC C,  69/2/2020,  P.554
Keywords: Broaching, Machining, Modelling, Chip formation
Abstract : Broaching is a unique machining process with high accuracy and surface quality, which is employed in mass and batch production for the manufacture of components with highly complex geometries. It involvves the use of multiple-edged complex tools in which the cutting edges are arranged with an offset also known as “rise per tooth” that determines the depth of cut per tooth. This paper presents the state-of-the-art of both the experimental and modelling aspects of broaching, and identifies the most important features related to this machining process. This includes a critical assessment of specifically designed broaching setups and their applicability and/or limitations compared to the machines used in industry. Contributions from academia and industry are included to support a comprehensive report of recent advances, as well as a roadmap for future developments.

 STC Cross-STC 

Self‐optimizing machining systems
H.‐C. Möhring (2), P. Wiederkehr (2), K. Erkorkmaz (1), Y. Kakinuma (2)  
STC Cross-STC,  69/2/2020,  P.740
Keywords: Machining, Machine Tool, Process Control
Abstract : In this paper the idea of Self‐Optimizing Machining Systems (SOMS) is introduced and discussed. Against the background of Industry 4.0, here the focus is the technological level of discrete workpiece production by mechanical machining processes utilizing related machine tools and equipment. Enabling technologies, principles, and methods are described that allow for the implementation of machining systems which are capable of adapting their parameters and settings autonomously, in order to optimize for productivity, quality, and efficiency in manufacturing. Following a description of the meaning and a definition of SOMS as well as a historical retrospection, the required elements of SOMS are discussed and exemplary approaches are presented. Based on sophisticated process planning, monitoring, adaptive control, simulation, artificial intelligence, and machine learning, strategies, state‐of‐the‐art solutions for self‐optimization in machining applications are introduced. Several examples showcase how different types of enabling technologies can be integrated synergistically, to improve the manufacturing of parts by SOMS. Finally, the future potential of SOMS as well as challenges and needs are summarized. The paper especially considers the results of the CIRP Cross‐STC Collaborative Working Group on SOMS.
Urban Production: State of the Art and Future Trends for Urban Factories
Christoph Herrmann (2), Max Juraschek, Peter Burggräf, Sami Kara (1)  
STC Cross-STC,  69/2/2020,  P.764
Keywords: Urban Factories, Urban Production, Cyber-Physical Production Systems, Urban Economics, Sustainable Development
Abstract : Ongoing urbanization and increasing decentralization of production have increased interest in the urban factory concept. Urban factories are production systems located in an urban environment that make use of the unique resources and characteristics of their surroundings to create products locally with a potentially high degree of customer involvement. This paper explores key technologies and methods, enabling production in cities and requirements to expand and support the urban factory concept. Industry examples are presented to highlight the opportunity that urban factories provide to deliver better, more customizable products at a lower cost, lower environmental impact and shorter lead-time. In general, there are still high uncertainties on how the underlying physical and immaterial exchange flows of urban factories influence urban systems and vice versa. Technological solutions fostering positive urban production systems are mainly coming from single disciplinary backgrounds and are increasingly transferred to the application in urban production sites.

 STC Dn 

Design for additive manufacturing: Framework and methodology
Tom Vaneker (2), Alain Bernard (1), Giovanni Moroni (2), Ian Gibson, Yicha Zhang  
STC Dn,  69/2/2020,  P.578
Keywords: Additive Manufacturing, Design, DfAM
Abstract : In recent decades additive manufacturing (AM) has evolved from a prototyping to a production technology. It is used to produce end-use-parts for medical, aerospace, automotive, and other industrial applications from small series up to 100,000 of commercially successful products. Metal additive manufacturing processes are relatively slow, require complex preparation and post-processing treatment while using expensive machinery, resulting in high production costs per product. Design for Additive Manufacturing (DfAM) aims at optimizing the product design to deal with the complexity of the production processes, while also defining decisive benefits of the AM based product in the usage stages of its life cycle. Recent investigations have shown that the lack of knowledge on DfAM tools and techniques are seen as one of the barriers for the further implementation of AM. This paper presents a framework for DfAM methods and tools, subdivided into three distinct stages of product development: AM process selection, product redesign for functionality enhancement, and product optimization for the AM process chosen. It will illustrate the applicability of the design framework using examples from both research and industry.


Damage in metal forming
A.E. Tekkaya (1), P.-O. Bouchard, S. Bruschi (1), C.C. Tasan  
STC F,  69/2/2020,  P.600
Keywords: Damage, Metal forming, Product properties
Abstract : Physical mechanisms of ductile damage in metal forming, experimental characterization methods for damage, and models predicting the damage level in formed components are reviewed. Applications of damage analysis in metal forming processes reveal that damage in metal formed parts is not failure, but a product property that accumulates between processes. Various metal forming process designs demonstrate that damage in formed products can be reduced and their performance can be increased. Static and fatigue strength, impact toughness, stiffness, and formability are typical examples of performance indicators that can be improved by damage-based process design. Potential scientific and technological challenges are addressed to realize damage-controlled metal forming processes.


Interactions of grinding tool and supplied fluid
C. Heinzel (2), B. Kirsch, D. Meyer (2), J. Webster (1)  
STC G,  69/2/2020,  P.624
Keywords: Grinding wheel, Fluid, Tool cleaning
Abstract : This paper reviews the physical and chemical interactions between the rotating tool and the supplied fluid in grinding. The mechanisms of this tool-fluid interaction are the key for high performance grinding processes due to an efficient fluid supply and resulting in a minimal thermomechanical impact on workpiece and tool. Reduced wear, increased surface finish, suitable subsurface properties of the machined material, increased material removal rates, and also energy efficiency can be achieved. In this context, the fluid supply towards the contact zone between tool and workpiece, the tool cleaning with high pressure cleaning nozzles as well as (tribo)-chemical phenomena between the abrasive layer and the supplied fluid are analysed and discussed. Finally, knowledge gaps are revealed which are indicating future research needs.


Energy Efficient Machine Tools
Berend Denkena (1), Eberhard Abele (1), Christian Brecher (1) , Marc-André Dittrich, Sami Kara (1), Masahiko Mori (1)  
STC M,  69/2/2020,  P.646
Keywords: Energy efficiency, Machine tool, Metal cutting
Abstract : The growing global energy demand from industry results in significant ecological and economical costs. Aiming to decrease the impact of machining operations, an increasing number of research activities and publications regarding energy efficient machine tools and machining processes can be found in the literature. This keynote paper provides an overview of current machine- and process-related measures to improve the energy efficiency of metal cutting machine tools. Based on an analysis of the energy requirements of machine tool components, design measures to reduce the energy demand of main and support units are introduced. Next, methods for an energy efficient operation of machine tools are reviewed. Furthermore, latest developments and already available energy efficiency options in the machine tool industry are discussed. The paper concludes with recommendations and future research questions for more energy efficient machine tools.


Big data analytics for smart factories of the future
Robert X. Gao (1), Lihui Wang (1), Moneer Helu (3), Roberto Teti (1)  
STC O,  69/2/2020,  P.668
Keywords: Digital Manufacturing System, Information, Learning
Abstract : Continued advancement of sensors has led to an ever-increasing amount of data of various physical nature to be acquired from production lines. As rich information relevant to the machines and processes are embedded within these “big data”, how to effectively and efficiently discover patterns in the big data to enhance productivity and economy has become both a challenge and an opportunity. This paper discusses essential elements of and promising solutions enabled by data science that are critical to processing data of high volume, velocity, variety, and low veracity, towards the creation of added-value in smart factories of the future.


Dimensional artefacts to achieve metrological traceability in advanced manufacturing
S. Carmignato (2), L. De Chiffre (1), H. Bosse (3), R.K. Leach (2), A. Balsamo (1), W.T. Estler (1)  
STC P,  69/2/2020,  P.693
Keywords: Manufacturing metrology, Traceability, Dimensional artefacts
Abstract : Dimensional measurements play a central role in enabling advanced manufacturing technologies, enhancing the quality of products and increasing productivity. This role becomes even more important in the context of Industry 4.0, where reliable and accurate digital models of products, processes and production systems are needed. To establish the traceability chain that links measurements in production to the length unit, dimensional artefacts – ranging from measurement standards to calibrated workpieces – are fundamental. The paper examines dimensional artefacts, discussing their characteristics, availability and role in supporting production by establishing metrological traceability, and provides guidelines for their selection, use and development.


Manufacturing of Multiscale Structured Surfaces
Ekkard Brinksmeier (1), Bernhard Karpuschewski (1), Jiwang Yan (2), Lars Schönemann  
STC S,  69/2/2020,  P.717
Keywords: Manufacturing, Structure, Multiscale
Abstract : Multiscale structured surfaces are a way to provide advanced, otherwise not attainable functionality on a technical part. Applications of such parts can be manifold, and numerous works have already covered the transfer of natural examples into bio-inspired surfaces or the geometrical and functional metrology of such surfaces. After briefly presenting typical functionalities of multiscale structured surfaces, this keynote paper will focus on the available manufacturing processes and review their capabilities to generate multiscale structured surfaces. To compare such processes, the so-called “multiscality” is defined that characterizes the structured surfaces according to the lateral and vertical extent of the individual stacked elements and is used as a first indicator to assess the difficulty of their manufacture. As the boundaries of what is considered a multiscale structure are diffuse, ranges of low, medium and high multiscality are defined instead. After presenting the state of the art of manufacturing processes currently utilized for the manufacture of (not only multiscale) structured surfaces, this keynote paper summarizes the capabilities of single-step and multi-step/multi-physics approaches for their applicability across different scales and gives an outlook on which processes could potentially become relevant in the future.