CIRP Annals Online sorted by Year and Volume




Autonomous Processes in Assembly Systems
B. Scholz-Reiter (2), M. Freitag  
STC A,  56/2/2007,  P.712
Keywords: Assembly, Control, Autonomous process
Abstract : Todays assembly systems have to be flexible to adapt quickly to an increasing number and variety of products and changing demand volume. To manage these dynamics, flexible, reconfigurable, and autonomous assembly systems were proposed and partly realised in the last two decades. The flexibility and adaptability is realised by clustering the assembly system into subsystems and modules which get a certain degree of autonomy and control themselves in a decentralised way. This keynote paper will present the general principles of autonomy and the proposed concepts, methods and technologies to realise autonomous processes in assembly systems. Different approaches for design and autonomous operation of assembly will be explained and future trends towards fully autonomous components of an assembly system as well as autonomous parts and products will be discussed.


On the measurement of temperature in material removal processes
M.A. Davies (2), T. Ueda (2), R. M'Saoubi (2), B. Mullany (3), A.L. Cooke  
STC C,  56/2/2007,  P.581
Keywords: Material Removal, Temperature, Measurement
Abstract : Because it is key to understanding the performance of material removal processes and resultant workpiece quality, the measurement of temperature during material removal is done extensively. We review several widely used temperature measurement methods and show how they can be applied to temperature monitoring during material removal. Since there is little documentation on measurement uncertainties as relates to material removal, this paper outlines the physics of each method, detailing the sources and evaluation of uncertainty. Finally, using criteria critical in measuring material removal, methods are compared, and the results presented in guide-format for participants in this field of work.

 STC Dn 

A Scientific Foundation of Collaborative Engineering
S.C-Y. Lu (1), W. Elmaraghy (1), G. Schuh (2),R. Wilhelm (2)  
STC Dn,  56/2/2007,  P.605
Keywords: Design, Manufacturing, Collaboration
Abstract : Collaborative engineering is the practical application of collaboration sciences to the engineering domain. In todays highly connected technology-driven economy, the production industry must rely on the best practices of collaborative engineering to stay competitive when designing, manufacturing and operating complex machines, processes, and systems on a global scale. Despite its importance, collaborative engineering is currently more of a practiced art than a scientific discipline. A better understanding of how engineers should collaborate with all stakeholders to accomplish complex tasks that fulfill our increasing social responsibilities is a grand challenge. However, because we currently lack well-defined sciences of human collaboration, we must first establish a scientific foundation of collaborative engineering to develop this emerging field into a rigorous discipline. This paper reports on the CIRP communitys collective efforts to establish such a scientific foundation according to the “Observation -> Hypothesis -> Theory” development pathway. Our objective is to spearhead the rigorous development of this new human-centered engineering discipline, so that useful knowledge can be generated to educate students and practical guidelines can be developed to enable engineers to become more productive collaboration leaders in the new global production industry.


Consolidation phenomena in laser and powder-bed based layered manufacturing
J.-P. Kruth (1), G. Levy (1), F. Klocke (1), T.H.C. Childs (1)  
STC E,  56/2/2007,  P.730
Keywords: Rapid Prototyping and Manufacturing, Selective Laser Sintering (SLS), Selective Laser Melting (SLM)
Abstract : Layered manufacturing (LM) is gaining ground for manufacturing prototypes (RP), tools (RT) and functional end products (RM). Laser and powder bed based manufacturing (i.e. selective laser sintering/melting or its variants) holds a special place within the variety of LM processes: no other LM techniques allow processing polymers, metals, ceramics as well as many types of composites. To do so, however, quite some different powder consolidation mechanisms are invoked: solid state sintering, liquid phase sintering, partial melting, full melting, chemical binding, etc. The paper describes which type of laser-induced consolidation can be applied to what type of material. It tries to understand the underlying physical mechanisms and the interaction with the material properties. The paper demonstrates that, although SLS/SLM can process polymers, metals, ceramics and composites, quite some limitations and problems cause the palette of applicable materials still to be limited. There is still a long way to go in tuning the processes and materials in order to enlarge the applicability of LM. This is not surprising if one compares it to the decades of R&D work devoted to tuning processes and materials for hot or cold forming, metal cutting (e.g. development of free machining steels), casting and injection moulding (including powder injection moulding: MIM, CIM, etc.).


Incremental Bulk Metal Forming
P. Groche (2), D. Fritsche, E. A. Tekkaya (2), J.M. Allwood (2), G. Hirt, R. Neugebauer (1)  
STC F,  56/2/2007,  P.635
Keywords: Forming, Metal, Incremental
Abstract : Incremental bulk forming is the oldest known technique in metal working. Many developments in this field have dramatically changed our society. Today incremental bulk forming processes are applied to quality products in small and large series production. Numerous advances have been realized. The motivation for using these processes is presented here. After a general definition of incremental processes and a classification of incremental bulk forming in particular, some innovative product and process examples are given that show the potential. Finally recent progress and challenges are illustrated in detail. This includes the development of new machinery for incremental bulk forming, advanced methods for process planning, occurrence of failure modes and the properties of finished products.


Thermal Analysis of Grinding
S. Malkin (1), C. Guo (3)  
STC G,  56/2/2007,  P.760
Keywords: Grinding, Temperature, Analysis
Abstract : Thermal damage is one of the main limitations of the grinding process, so it is important to understand the factors which affect grinding temperatures. This paper presents an overview of analytical methods to calculate grinding temperatures and their effect on thermal damage. The general analytical approach consists of modeling the grinding zone as a heat source which moves along the workpiece surface. A critical factor for calculating grinding temperatures is the energy partition, which is the fraction of the grinding energy transported as heat to the workpiece at the grinding zone. For shallow cut grinding with conventional abrasive wheels, the energy partition is typically 60%–85%. However for creep-feed grinding with slow workspeeds and large depths of cut, the energy partition is only about 5%. Such low energy partitions are attributed to cooling by the fluid at the grinding zone. Heat conduction to the grains can also reduce the energy partition especially with CBN abrasives which have high thermal conductivity. For High Efficiency Deep Grinding (HEDG) using CBN wheels with large depths of cut and fast workspeeds, preheated material ahead of the grinding zone is removed together with the chips, thereby lowering the temperature on the finished surface. Analytical models have been developed which take all of these effects into account. Much more research is needed to better understand and quantify how grinding temperatures affect the surface integrity of the finished workpiece.


Mechatronic Systems for Machine Tools
R. Neugebauer (1), B. Denkena (2), K. Wegener  
STC M,  56/2/2007,  P.657
Keywords: Machine tool, Mechatronic, Adaptronic
Abstract : This paper reviews current developments in mechatronic systems for metal cutting and forming machine tools. The integration of mechatronic modules to the machine tool and their interaction with manufacturing processes are presented. Sample mechatronic components for precision positioning and compensation of static, dynamic and thermal errors are presented as examples. The effect of modular integration of mechatronic system on the reconfigurability and reliability of the machine tools is discussed along with intervention strategies during machine tool operation. The performance and functionality aspects are discussed through active and passive intervention methods. A special emphasis was placed on active and passive damping of vibrations through piezo, magnetic and electro-hydraulic actuators. The modular integration of mechatronic components to the machine tool structure, electronic unit and CNC software system is presented. The paper concludes with the current research challenges required to expand the application of mechatronics in machine tools and manufacturing systems.


Changeable Manufacturing - Classification, Design and Operation
H.-P. Wiendahl (1), H.A. ElMaraghy (1), P. Nyhuis, M.F. Zaeh (2),H.-H. Wiendahl, N. Duffie (1), M. Brieke  
STC O,  56/2/2007,  P.783
Keywords: Manufacturing, Factory, Changeability
Abstract : Flexibility and changeability are key enablers for meeting the challenges of a global market. The paper first describes the main change drivers and takes then a deeper look at how changeability in a manufacturing en-terprise can be classified and operationalized. The next sections are devoted to changeability in reconfigur-able manufacturing systems, assembly systems and factories including buildings and infrastructure. New challenges, perspectives and approaches for process plan reconfiguration as well as for Production Planning and Control are discussed. Finally, the evaluation and economic justification of changeability are addressed and a control loop of changeability is presented.


Metrology of freeform shaped parts
E. Savio (2), L. De Chiffre (1), R. Schmitt   
STC P,  56/2/2007,  P.810
Keywords: Freeform, Dimensional, Metrology
Abstract : The scope of this keynote paper is to present the state of the art in the metrology of freeform shapes with focus on the freeform capabilities of the most important measuring techniques and on related metrological issues. Some examples of products are presented, for which the metrology of freeform shapes is important to guarantee the desired functional performance of the product. A classification of freeform measuring tasks and the corresponding metrological requirements are presented. A review of the most important measuring techniques is presented along with their capabilities for freeform measuring tasks. Specification and verification of freeform surfaces, including data evaluation and comparison to specifications are discussed, along with the measurement uncertainty and traceability of freeform measurements.


The Design and Manufacture of Biomedical Surfaces
J.J. Ramsden, D.M. Allen (1), D.J. Stephenson (2), J.R. Alcock, G.N. Peggs (1), G. Fuller, G. Goch (1)  
STC S,  56/2/2007,  P.687
Keywords: Biomedical, Surface, Metrology
Abstract : Surfaces are the primary place of contact between a biomaterial and its host organism. Typically, prostheses have to fulfil demanding structural and mechanical requirements, yet the material best for those functions may be bio-incompatible. Surface treatment or coating provides a means to overcome that problem, which means both integration within the host physiology and stabilization with respect to corrosion and wear. The adsorption of biomacromolecules is pivotal for biocompatibility. The impossibility of keeping proteins away from most implants means that very careful consideration has to be given to this aspect, and both prevention (for bloodstream implants) and promotion (for bone replacement and repair) occur with equal importance. This paper also considers the metrology of relevant physical and chemical aspects of surfaces.