THE INTERNATIONAL ACADEMY FOR PRODUCTION ENGINEERING

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 STC A 

Development of new concepts and software tools for the optimization of manual assembly systems
K. Feldmann (1), S. Junker  
STC A,  52/1/2003,  P.1
Keywords: Assembly, Flexible Manufacturing System, Simulation
Abstract : Due to growing numbers of differing products and variants, assembly systems with optimized manual workstations have become an efficient alternative to highly automated but less flexible production systems. Especially in the final stage of the product assembly, the flexibility of human employees enables them to meet the requirements for assembling various products and changing volumes. In order to create highly efficient production systems based on human work, it is necessary to develop innovative concepts for the design and organization of manual assembly structures. Another major issue is the development of software tools allowing the facility planner to simulate and optimize the complete design of the assembly structure such as the material flow or manual workstations, e.g. with respect to ergonomics, before construction. These requirements have led to a comprehensive research framework for manual assembly systems.
Integrating Augmented Reality in the Assembly Domain - Fundamentals, Benefits and Applications
G. Reinhart (2), C. Patron  
STC A,  52/1/2003,  P.5
Keywords: Assembly, Augmented Reality, Computer-aided planning
Abstract : Augmented Reality (AR) is a new form of human-machine interaction which overlays computer-generated information on the real world environment, e.g. through a semi-transparent, head-mounted display. With AR, presented information is derived from the real environment and is thus context-sensitive. Augmented Reality can therefore enhance a user's view with virtual information that is sensitive to the current state of the surrounding real world. While Virtual Reality Technology (VRT) is commonly used in the automotive and aircraft industry, there exists few research approaches in the field of Augmented Reality. This contribution gives a detailed introduction to AR systems, and describes the capabilities and benefits of AR in the field of assembly. As an application, a modular AR system for guiding manual assembly and for use in assembly planning is described. Furthermore, a method for integrating AR into the planning process of manual assembly stations is presented.
Assembly Reliability Evaluation Method (AREM)
T. Suzuki, T. Ohashi, M. Asano   / T. Arai (1)
STC A,  52/1/2003,  P.9
Keywords: Design, Quality, Assembly
Abstract : This paper proposes a new design system for assembly quality evaluation called AREM. It is based on the assembly fault occurrence model reflecting both product design and assembly shops. It prevents faults in assembly shops related to the design of the product. The system has three distinctive features: estimation of faults caused by design, extraction of faulty parts or faulty operations, and analysis of fault phenomena. AREM can distinguish the responsibility of the design and the shop quantitatively. This method is being used for various products in practical production lines, and has proven to be effective.
Rapid Deployment of Reconfigurable Assembly Fixtures using Workspace Synthesis and Visibility Analysis
Z. Kong, D. Ceglarek (2)  
STC A,  52/1/2003,  P.13
Keywords: Reconfigurable fixture, Workspace synthesis, Visibility
Abstract : Due to rapid changes in recent market demands, shortened production ramp-up/launch and model changeover of new products with simultaneous manufacturing of family of products on a single production line is becoming inevitable. This requires systematic methods for rapid design and analysis of reconfigurable fixture workspace synthesis and visibility. This paper presents an integrated approach for rapid reconfigurable fixture deployment which is based on (1) the procrustes analysis integrated with a pairwise optimization for fixture workspace configurations synthesis; and (2) screen space transformation-based visibility analysis for rapid fixture calibration. A case study and simulations illustrate the proposed approach.
Self-adjustment of Micro-mechatronic Systems
M. Tichem, B. Karpuschewski (2), P.M. Sarro   
STC A,  52/1/2003,  P.17
Keywords: Micro-assembly, Mechatronic, Self-adjustment
Abstract : The paper provides an introduction to various methods of creating composed products in the micro-domain. The methods are evaluated using different criteria, including the potential to reduce difficult handling operations. In the second part, a case study is described on self-adjustment. The components are coarsely aligned with respect to each other using for instance (semi) automatic production machines. In the second stage, the components are precisely aligned with respect to each other using assembly functions that are integrated with the product. The case considered is opto-electronic devices. On basis of a MEMS device self-adjustment is used to position optical fibres.
Automated Handling of Non-Rigid Parts
G. Seliger (2), F. Szimmat, J. Niemeier, J. Stephan  
STC A,  52/1/2003,  P.21
Keywords: Assembly automation, Handling device, Non-rigid parts
Abstract : Handling of non-rigid parts is a challenging and promising field of industrial automation. Specific processes based on various material properties of textiles, leather, paper, foils emerge into innovative tools. Flexural rigidity, surface condition, permeability, and geometric variance determine process requirements. The behavior of materials is experimentally analyzed and modeled in order to increase process reliability. Cases of ply separation, clearing of cutting tables, positioning, and transporting of non-rigid parts are introduced. Areas of applications in clothing, electronics, and vehicle manufacturing are presented.
Simplified Lifecycle Assessment for the Early Design Stages of Industrial Products
H. Kaebernick (1), M. Sun, S. Kara  
STC A,  52/1/2003,  P.25
Keywords: Environmental design, Impact evaluation, Lifecycle assessment
Abstract : Simplified Lifecycle Assessment (LCA) methodologies are very useful tools in the early design stages for estimating the environmental impacts of product alternatives and for predicting environmental costs or burdens for manufacturers. A new methodology, presented in this paper, is based on the analysis of full LCA case studies. It calculates the product's Environmental Performance Indicator by using two sets of energy-based and material-based Impact Drivers. Further simplification can be achieved by grouping the products according to their material/energy ratio and by using simple regression equations. A wide range of case studies is used to compare the simplified results with the full LCA results.
Pro-active Life Cycle Engineering Support Tools
J. Duflou, W. Dewulf, p. Sas   / P. Vanherck (1)
STC A,  52/1/2003,  P.29
Keywords: Environmental, Conceptual Design, Life Cycle
Abstract : The extending responsibility of manufacturers regarding their products' environmental impact has led to the development of a wide range of Life Cycle Engineering tools and techniques. However, their efficiency has yet been limited by the need for detailed input data, typically unavailable in the early conceptual phases of design, when most far-reaching improvements can be achieved. This problem particularly holds true in a design environment of one-of-a-kind products, such as in many automation and machine design projects, where no previous generation products are available to provide the required analysis feedback. This paper presents a set of pro-active support tools that are specifically developed for the early design phases and cover the analytical as well as the creative steps of design. On the one hand, Eco-Cost Estimation Relationships form the core of the Eco-PaS system, which estimates the technical parameters, needed as input for most assessment tools, as a function of the functional parameters available in the concept development phase. On the other hand, the Ecodesign Knowledge System classifies both knowledge and user situations according to a common set of domain models in order to supply, at any time, adequate Life Cycle Engineering guidance, tailored to the specific user situation.
Integration of Economics into Engineering with an Application to the Recycling Market
K. Ueda (1), N. Nishino, S.H. Oda  
STC A,  52/1/2003,  P.33
Keywords: Life Cycle Management, Decision Making, Economics
Abstract : This paper describes integration of recent economics concepts into engineering. Direct and indirect effects of new technology on its users and society depend on the economic system in which it operates. They can be formulated and analyzed by experimental economics, computational economics and the market microstructure theory, which have all emerged recently in economics. We describe how such integration can be done both in general and with an example: a recycling economy model. An integrated approach of engineering and economics that treats human behavior, market structure and technology on an empirical and theoretical basis makes it possible to describe a process whereby used product units are collected from consumers for reuse.
Life Cycle Simulation System for Life Cycle Process Planning
S. Takata (1), T. Kimura  
STC A,  52/1/2003,  P.37
Keywords: Life cycle, Simulation, Reuse
Abstract : To realize closed loop manufacturing, it is essential to design product life cycles and to plan life cycle processes properly. Life cycle simulation has been recognized as an effective tool in this direction. In this paper, we present a life cycle simulation system developed as a general tool for life cycle design and management. The system includes functions for modelling and controlling each life cycle process in a flexible manner. The system maintains usage history of products and parts independently taking the reuse of parts into account. Examples of the simulation are shown for both a rapid life cycle scenario and for a part sharing scenario over the product generations.

 STC C 

Creation of Flat-End V-Shaped Microgroove by Non-Rotational Cutting Tool
Y. Takeuchi (1), M. Murota, T. Kawai, K. Sawada  
STC C,  52/1/2003,  P.41
Keywords: Micromachining, Non-rotational cutting, Flat-end microgroove
Abstract : The study deals with the creation of V-shaped microgrooves with flat-end, which play an important role in case of generating intermittent grooves. Microgrooves by use of rotational cutting tool have a long radius in disengagement from the workpiece. Thus, two cutting methods by use of non-rotational cutting tool are devised so that V-shaped microgrooves with flat-end can be created. The first method makes use of straight chips generated under some cutting condition. Non-rotational cutting tool compresses the chips at the groove end and cuts the excessive parts of chips over the plane. The second method is to transcribe the surface of a tool sticked perpendicularly into a workpiece. As a result, it is experimentally found that the methods enable the creation of flat-end microgrooves.
Development of Drill Geometry for Burr Minimization in Drilling
S.L. Ko, J.E. Chang   / S. Kalpakjian (1)
STC C,  52/1/2003,  P.45
Keywords: Burr, Drilling, Burr Minimization
Abstract : The researchers carried out drilling tests using drills of various shapes to determine burr minimization. The ultimate objective of this study was to develop a compatible drill shape to minimize burr formation. For the experiment general carbide drills, round drills, chamfer drills and step drills are designed and manufactured. Burrs are generated under various cutting conditions using four different materials. A laser sensor was used to measure the burr dimensions. As a result of the experiments, step drill with specific step angle and step size is suggested for burr minimization.
Theoretical Estimation of Machined Surface Profile Based on Cutting Edge Movement and Tool Orientation in Ball-nosed End Milling
Y. Mizugaki, K. Kikkawa, H. Terai, M. Hao   / T. Sata (1)
STC C,  52/1/2003,  P.49
Keywords: Ball end milling, Machined surface geometry, Geometric simulation
Abstract : This paper presents the theoretical estimation method of machined surface profile without actual machining in ball-nosed end milling. The fundamental simultaneous equations of identifying the cusp height at any point of a workpiece in the simulated surface have been successfully derived from the geometric relationship between the cutting edge movement and the normal line at the point. By the numerical calculation, the machined surface profile can be estimated and illustrated graphically. It was found that the maximum and minimum cusp heights exist in a narrow range of tool orientation less than 3 degrees near the normal direction.
Effects of Synchronizing Errors on Cutting Performance in the Ultra-High-Speed Tapping
J.H. Ahn, D.J. Lee, S.H. Kim, H.Y. Kim, K.K. Cho (1)  
STC C,  52/1/2003,  P.53
Keywords: Tapping Torque, Thread Quality Synchronizing Error
Abstract : Synchronizing errors between the spindle motor and the z-axis motor directly influences the cutting characteristics in tapping, because the tapping process is accomplished by synchronizing the movement of the z-axis with the revolutionary spindle motion. The excessive synchronizing error can cause tap breakage due to the abrupt increase of cutting torque or damage the thread accuracy by overcutting the already cut threads. This paper describes the effects of the synchronizing errors on the cutting performance in the ultra high-speed tapping and presents a minimum level of synchronizing errors necessary to maintain the quality of the cut thread.
Development of a High Performance End Mill - Based on the Analysis of Chip Flow Generated by Curved Rake
Y. Kimura   / H. Takeyama (1)
STC C,  52/1/2003,  P.57
Keywords: End milling, Chip, Chip flow simulation
Abstract : To achieve high efficiency machining with end mills, the analysis of chip flow is necessary. Firstly, the constraints which a curved rake face gives to chip flow are analyzed, and the existence of the third component of angular velocity of the chip, which is different from those of up-curl and sideward curl, is found. Secondly, based on the analysis, a simulation model of chip flow is proposed, thus leading to the development of a high performance end mill. Finally, the chip configurations and chip flow obtained by the simulation are compared with those observed in actual cutting tests for verification.
Tribological Characteristics and Cutting Performance of Lubricant Esters for Semi-dry Machining
T. Wakabayashi, I. Inasaki (1), S. Suda, H. Yokota  
STC C,  52/1/2003,  P.61
Keywords: Machining, Fluid, Environment
Abstract : In semi-dry machining, a very small amount of a lubricant plays an important role to achieve a successful operation. However, there has so far been little investigation on the tribological behavior of lubricants for semi-dry application in connection with their cutting performance. To understand the tribological characteristics of such lubricants, therefore, fundamental examinations are made with the aid of a controlled atmosphere machining apparatus. Some practical operations of semi-dry machining are also carried out using several biodegradable lubricant esters. These esters demonstrate the satisfactory cutting performance and their effectiveness is discussed in detail with their lubricating action.
Supernitrides: A novel generation of PVD hardcoatings to meet the requirements of high demanding cutting applications
G. Erkens, R. Cremer, T. Hamoudi, K.-D. Bouzakis (1), J. Mirisidis, S. Hadjiyiannis, G. Skordaris, A  
STC C,  52/1/2003,  P.65
Keywords: PVD, Milling, Supernitride coatings
Abstract : Based on a unique sputtering technology using highly ionized plasmas a novel grade of high performance hard coatings, the Supernitrides with macro free morphology were developed. Within the scope of the investigations described, a characteristic (Ti,AI)N based Supernitride variant, with an AIN content close to the conductivity limit of 65-67mol-%37; AIN was deposited on cemented carbide inserts. The films mechanical properties were extracted by means of nanoindentations and impact tests and compared to the corresponding ones of an effective state of the art (Ti46AI54)N coating. Milling investigations, conducted with both previous mentioned coatings, demonstrated the enhanced cutting performance of the applied Supernitride coating, especially at elevated cutting temperatures.
Gains Achieved by Using New Generations of Plastic Injection Mold Steels
C. Le Calvez (3), G. Poulachon, B. Coulon, A. Ponsot, M. Dessoly, A. Moisan (1), J. Rech  
STC C,  52/1/2003,  P.69
Keywords: Mold Steel, Modelling, Milling
Abstract : The analysis of the plastic injection mold market shows the interest of reducing milling costs; the improvement of mold steel machinability is one response to rough milling. The quantification of the gains offered by new mold steels requires the development of more accurate and suitable comparison methods to appreciate the response to rough milling with toric milling cutters. The methods proposed in this paper take into account more reliable tool-life criteria. Results of comparison tests are analysed from scientific, technological and economical points of view. Moreover, the deduced models lead to a better understanding of the respective roles of each parameter.
Wear Mechanisms of New Tool Materials for Ti-6Al-4V High Performance Machining
N. Corduan, T. Himbert, G. Poulachon, M. Dessoly, M. Lambertin, J. Vigneau (1), B. Payoux   
STC C,  52/1/2003,  P.73
Keywords: Titanium-alloy, Ceramic-tools, Wear
Abstract : Nowadays, Ti-6Al-4V turning is mastered for cutting speed lower than 60 m/min by using carbide and high-speed steel tools. At higher cutting speed, chemical and mechanical properties of Ti-6Al-4V cause complex wear mechanisms such as adhesion and diffusion. Thus, to machine over 100 m/min without using high-pressure cooling, new tool materials need to be tested and their behaviour understood. This paper presents the interactions between polycrystalline diamond (PCD), cubic crystalline boron nitride (CBN), and TiB2 coated carbide with titanium based alloy. The different wear patterns are not only strongly linked to the chemical reactions, but also to the different phase changes, which occur with PCD and CBN tools.
On the measurement and prediction of temperature fields in machining AISI 1045 steel
M.A. Davies (2), Q. Cao, A.L. Cooke, R. Ivester  
STC C,  52/1/2003,  P.77
Keywords: Measurement, Finite Element Method, Temperature
Abstract : Infrared microscopic measurements of the temperature fields at the tool-chip interface in steady-state, orthogonal, machining of AISI 1045 steel are presented for a range of chip thicknesses. The measurements are verified using an energy balance method and simple finite difference calculations (see [14]). These results are compared to the predictions of a finite element calculation using a commercial package for three different material models obtained from the literature. Results are highly dependent on the material model and friction behavior, indicating that caution be used when finite element analysis is to predict rather than interpret machining temperatures.
Cross Reference Models for Estimating Unknown Principal Force
M. Dölen, B. Kaftano?lu (1), R.D. Lorenz  
STC C,  52/1/2003,  P.81
Keywords: Cutting, End-milling, Modeling
Abstract : This paper focuses on the problem of estimating the unknown principal cutting force component with the available knowledge on the other component. The paper presents two compact (end-milling) process models. Using these models, two cross-reference models, which explore the functional relationships among the free parameters of these models, are developed. Within the framework of constructing an unknown force component, the estimation performance of the proposed models along with their inherent limitations are assessed through rigorous experimental study in this paper.
Development of a Five-axis Milling Tool Path Generation Algorithm based on Faceted Models
B. Lauwers (2), G. Kiswanto, J.-P. Kruth (1)  
STC C,  52/1/2003,  P.85
Keywords: Computer aided manufacturing (CAM), Milling, Faceted model
Abstract : This paper describes the development of a 5-axis milling tool path generation algorithm based on faceted or tessellated models. In a first step, the developed algorithm optimises the tool inclination angle for maximal material removal rate in each cutter contact point. This is obtained by matching the tool profile of a flat end cutter with a temporary spline representing the curvature of the part surface in the tool contact point. In a second step, the elimination of gouging between the tool and the surface and a smooth behaviour of the tool inclination angle along the tool path is obtained by a combination of tool inclination angle adaptation and tool lifting along the normal vector. Finally, the paper describes some experimental results.

 STC Dn 

Knowledge Structuring for Function Design
B.R. Meijer, T. Tomiyama (2), B.H.A. van der Holst, K. van der Werff  
STC Dn,  52/1/2003,  P.89
Keywords: Design, Function, Knowledge Management
Abstract : Well-structured functional knowledge is essential to conduct function design as stated by well-known design methods, including Suh?s axiomatic design approach and one of Pahl and Beitz. Innovative design is a consequence of combining different types of knowledge sources, and obviously requires well-structured functional knowledge. The paper focuses on Suh?s axiomatic design approach. Through a design example, the paper shows that his first axiom (functional independence axiom) depends on such well-structured knowledge. This confirms that good design results not from functional independence of functional requirements but from such well-structured functional knowledge.
Design Knowledge Management with Reconstructible Structure
H. Koh, S. Ha, T. Kim, H.M. Rho (2), S.H. Lee  
STC Dn,  52/1/2003,  P.93
Keywords: Knowledge, Design, Knowledge representation
Abstract : Critical issue in knowledge management is how to increase the adaptability of knowledge as well as how to reconstruct similar knowledge. In order to construct the design knowledge for new products, designers need to reconstruct the design knowledge with new relationships. A new design knoledge expression method, Design DNA, is proposed in this work for representing complicated relationships of design knowledge. Design DNA facilitates rearrangement of design knowledge and promotes the flexibility of knowledge structure. Design DNA is based on Layout-oriented domain knowledge and Function-oriented domain knowledge, which enables to generatee new design knowledge that will result in new part geometries for given constraints on the part functions.
Structure of Failure Knowledge Database and Case Expression
Y. Hatamura (1), K. iino, K. Tsuchiya, T. Hamaguchi  
STC Dn,  52/1/2003,  P.97
Keywords: Failure, Recognition, Knowledge
Abstract : There are a number of failure databases that record information about events that have made negative effects on people, organizations, and the society. Although they serve the purpose of recording the events, they fail to prevent similar failures from repeating. The reason is the poorly organized information data and lack of impact on the information receiver. This paper proposes a data structure and an effective way of displaying the failure case information so the receiver understands the case and makes use of the information by avoiding the failure in similar situations and even leading the way to creation.
Biomimetics Applied to Centering in Microassembly
L.H. Shu (2), T.A. Lenau, H.N. Hansen (2), L. Alting (1)  
STC Dn,  52/1/2003,  P.101
Keywords: Design methodology, Microassembly, Positioning
Abstract : This paper describes the application of a biomimetic search method to develop ideas for centering objects in microassembly. Biomimetics involves the imitation of biological phenomena to solve problems. An obstacle to the use of biomimetics in engineering is knowledge of biological phenomena that are relevant to the problem at hand. The method described here starts with an engineering problem, and then systematically searches for analogous biological phenomena using functional keywords. This method is illustrated by finding and using analogies for the problem of positioning and centering objects during microassembly. Relevant phenomena identified involve microtubule organizing centers, photosystems, and retinal ganglion cells.
Designing Productive Manufacturing Systems without Buffers
T. Freiheit, M. Shpitalni (1), S.J. Hu, Y. Koren (1)  
STC Dn,  52/1/2003,  P.105
Keywords: Productivity, Manufacturing System Performance, Reconfigurable
Abstract : Modern industrial practice is to minimize work-in-process in order to eliminate inventory-carrying costs and quickly detect quality problems. Reduced work-in-process results from eliminating in-process buffers between operations in serial lines, but is accompanied by decreased system efficiency. Inventories are created before system expansion in order to offset production lost during construction. Furthermore, serial line expansion implies doubling line output. In reconfigurable manufacturing systems, new configurations that have not yet been fully explored by industry can be used to compensate for loss of buffered system isolation failure, creation of inventories, and step-size production expansion. Numerical models are applied to predict productivity and explicitly show the equivalency of alternative configurations to buffered serial transfer lines. Parallel-serial configurations as well as the newly proposed reserve capacity configurations are examined.
Integrative Design Environment to Improve Collaboration between Various Experts
F. Noel, D. Brissaud (2), S. Tichkiewitch (1)  
STC Dn,  52/1/2003,  P.109
Keywords: Co-operative Design, Knowledge Integration, Information Sharing
Abstract : This paper deals with the instrumentation of the collaboration between actors of various knowledge and know-how. Computer Aided Design technology lead to many resources supporting the digital mock-up. The CAD vendors answer integrates various software to deliver a single environment for every design activity. As an alternative, the paper describes an integrative environment. We assume that innovative design is based on the various and heterogeneous resources. Then we propose a common framework where any existent or future resources will connect to share knowledge about the product. Concepts handled by the integrative environment and technologies to support it are discussed.
Mechanical Bus for Modular Product Design
P. Gu (2), M. Slevinsky  
STC Dn,  52/1/2003,  P.113
Keywords: Design, Module, Mechanical Bus
Abstract : Modular products consist of detachable modules that can be manufactured, assembled, and serviced separately and may be reusable, recyclable, or remanufacturable upon product retirement. Thus, modular design can provide benefits to many aspects of product life cycle. To realize these benefits, the connections between modules must be designed to facilitate operations for parallel manufacturing, assembly as well as post product life activities. This paper presents a new concept of Mechanical Bus for facilitating modular and platform product design. The characteristics and features of Mechanical Buses have been identified including bus functions, locking and release mechanisms, positioning and locating features and so on. A design method for modular platform design using Mechanical Buses has also been developed. Examples and a case study will be included to illustrate the Mechanical Bus and modular platform product design method.
Product Platform Identification and Development for Evolutionary Customization
G.Q. Huang, S. Bin , G. Halevi (1)  
STC Dn,  52/1/2003,  P.117
Keywords: Product Development, Design Theory, Product Platform
Abstract : This paper is mainly concerned with the identification of an embryonic product platform from a family of products whose composition, configuration and characteristics are represented by Attributed Graphs. The problem becomes that of identifying the largest isomorphic sub-graph with the highest similarity. An algorithm is proposed for solving this problem together with several novel concepts.
Customizability Index Based on Information Content
J. Jiao, M.M. Tseng (1)  
STC Dn,  52/1/2003,  P.121
Keywords: Design, Product, Customization
Abstract : Developing product platforms has been recognized as an effective means to implement mass customization. This paper focuses on the customizability issue of design, that is, to evaluate the cost effectiveness of a design to be customized to meet individual customer needs. A customizability index is proposed to facilitate the analysis of customizability from both the customers and the manufacturer perspectives. It involves two dimensions. One is about the intrinsic nature of a design easy to be customized. The other is regarding the customer-perceived value of customization. The utility theory is introduced to model the customer-perceived value of each individual product feature. Conjoint analysis is introduced to explore customer preference for multiple product features. The customizability index is measured based on the information content metric. Customizability analysis manifests itself through the maximization of customer-perceived value while exploiting the potential of design to be customized specified by optimal customizability indices.
Reconstruction of Freeform Objects with Arbitrary Topology Using Neural Networks and Subdivision Techniques
F.-L. Krause (1), A. Fischer (2), N. Gross, J. Barhak  
STC Dn,  52/1/2003,  P.125
Keywords: Reverse engineering, Neural network method, Subdivision method
Abstract : In reverse engineering, laser scanned data is reconstructed into a CAD model. This paper presents a new reconstruction approach that integrates neural networks with subdivision techniques. The neural network technique creates a triangular mesh that approximates the shape of an object and detects its topology, where the subdivision approach applies smooth surfaces onto this mesh. The advantage of this method is that the reconstruction can be applied on objects with arbitrary topology, and the final model can be integrated with traditional CAD systems using a NURBS representation that preserves continuity. The feasibility of the method is demonstrated on freeform objects with arbitrary topology.
Geometric Simulation of NC Machining based on STL Models
Z.D. Zhou, J.D. Zhou, Y.P. Chen, S.K. Ong, A.Y.C. Nee (1)  
STC Dn,  52/1/2003,  P.129
Keywords: Machining simulation, Geometric modelling algorithm, STL model
Abstract : Presently, simulation models in virtual CNC machining simulation can be generated using commercial CAD software to provide dynamic 3D interactive virtual environments specifically designed for visualizing and analyzing the functionality of CNC machine tools and the material removal processes. However, these models generated using different CAD software have distinct individual formats, and are difficult to use in another simulation environment. This paper proposes to use the STL (stereolithography) models as the common models in machining simulation for bridging the incompatibility between different CAD software systems. The simulation results in the STL model format can be immediately used in rapid prototyping to produce the prototype and design changes can be reflected quickly from these prototypes. This will serve as a useful guide for the designers to make the necessary changes along the design process.
Integrated Tolerancing Process for Conceptual Design
J.-Y. Dantan, N. Anwer, L. Mathieu (2)  
STC Dn,  52/1/2003,  P.135
Keywords: Design process, Tolerancing Synthesis, Information modelling
Abstract : For car and aircraft industries, the management of geometrical variations has become an important issue in product design process and concurrent engineering. Indeed, designers need to manage dimensional and geometrical tolerances and to know information that contributed to their determination. The goal here is to put tolerancing in a concurrent engineering context. There are important questions that would need to be looked upon: How to integrate the tolerance synthesis in the design process? How to ensure the transition from function to geometrical specifications on parts? How to keep traceability of tolerances during the design process? Few answers exist today in academic works and there are few supports in CAD systems. Therefore, to build a coherent data model taken into account tolerances, we describe in this paper a multi-level approach that enables a tolerancing process integrated with conceptual design. The first level integrates information relating to functional aspects of an assembly. The second describes the structure of the assembly, and concerns the integration of functional needs and technological solutions. The last level translates functional requirements into geometrical requirements between/or on parts of the products, and provides the geometrical specifications on each part satisfying the geometrical requirements. This multi-level architecture is represented as an object oriented data model based on UML (Unified Modelling Language) that enable data management for functional tolerancing in design and keeping traces when querying about data.

 STC E 

New Ferro Powder for Selective Laser Sintering of Dense Parts
J.P. Kruth (1), L. Froyen, M. Rombouts, J. Van Vaerenbergh, p. Mercelis  
STC E,  52/1/2003,  P.139
Keywords: laser sintering, iron powder, rapid prototyping
Abstract : The paper describes a new powder composition specially developed for selective laser sintering (SLS). The aim is to obtain a ferro powder that can be sintered without need for a (sacrificial) polymer binder and that results in quasi dense parts that do not need any post-processing like furnace sintering, infiltration or HIP. The powder is a mixture of different types of particles (Fe, Cu, Ni and Fe3P). The composition and mixture ratio are justified by using phase diagrams. The powder has been tested using an own developed Nd:YAG SLS machine. The influence of process parameters (laser power, scan velocity, scan spacing and scan strategy) and the microstructural characteristics have been investigated. Attention is devoted to the binding mechanism (liquid phase sintering, through melting) and to the quality of resulting parts (density, balling effect, ?).
Modelling and Simulation of Micro-EDM
Z.Y. Yu, J. Kozak, K.P. Rajurkar (1)  
STC E,  52/1/2003,  P.143
Keywords: Electrical Discharge Machining, Modelling, Simulation.
Abstract : In micro EDM, simple-shaped tools are being used to machine complex 3D micro features because of the cost and difficulty in fabricating multiple complex-shaped micro electrodes. However, the tool wear adversely affects the accuracy of machined micro features. Therefore, a theoretical model for surface profile generation which takes into account the effect of tool wear is needed. This paper presents such a model and a simplified simulation algorithm. The experimental results of micro and macro EDM generated surface profiles confirm the validity of the proposed mathematical model and the simulation algorithm.
High Speed 3D Milling by Dry EDM
M. Kunieda (2), Y. Miyoshi, T. Takaya, N. Nakajima, Z.-B. Yu, M. Yoshida  
STC E,  52/1/2003,  P.147
Keywords: EDM, high speed machining, dry process
Abstract : This paper describes the high speed EDM milling of 3D cavities using gas as the working fluid. In this new process, the molten workpiece material is removed and flushed out of the working gap with the help of high-pressure gas flow. The advantages of this technique are the remarkably small tool electrode wear and the significantly high material removal rate especially when oxygen gas is used due to the extremely strong oxidation of steel workpieces. Experiments showed that the material removal rate increases dramatically when the discharge power density on the working surface exceeds a certain threshold due to thermally activated chemical reaction between the gas and workpiece material. The maximum removal rate obtained was almost equal to that of high speed milling of quenched steel by a milling machine. The machining accuracy was considerably better when the gas was sucked through the pipe electrode than jetted.
Electrical Discharge Surface Alloying of Ti and Fe Workpiece Materials Using Refractory Powder Compact Electrodes and Cu Wire
D.K. Aspinwall, R.C. Dewes, H.G. Lee, J. Simao   / P. McKeown (1)
STC E,  52/1/2003,  P.151
Keywords: Electrical discharge machining (EDM), Texture, Surface
Abstract : The paper reviews the use of metal powders dispersed in the dielectric fluid and refractory PM electrodes, to initiate workpiece surface modification during EDM. Experimental work details the effects of EDM parameters (up to 270 V) on the hardness / composition of the white layer following die sink machining of AISI H13 tool steel and roll texturing of 2%37; Cr steel using partially sintered PM electrodes. Similar data are presented following EDM scanning and wire cutting of standard Ti alloy Ti-6Al-4V and a ? TiAl. With AISI H13, recast layers were 5-20 µm thick and up to ~1350 HK0.025. When machining Ti-6Al-4V with WC/Co electrodes, recast microhardness was 600-2900 HK0.025. Wire cutting ? TiAl generated porous alloyed layers up to 115 µm thick with extensive cracks and no increase in bulk hardness.
Layer Generation Process on Work-piece in Electrical Discharge Machining
N. Mohri (2), Y. Fukusima, Y. Fukuzawa, T. Tani, N. Saito   
STC E,  52/1/2003,  P.157
Keywords: Electrical Discharge Machining, Ceramic, Surface
Abstract : In recent years, surface modification of metals and machining of insulating ceramics by electrical discharge machining (EDM) have been successfully carried out. In surface modification by EDM with semi-sintered electrodes, worn substances in the gap region form the material source of the layer generated on the work-piece surface. In the machining of insulating ceramics by EDM, a crystallized carbon layer or carbide layer from the working oil covers the surface of the insulator. Increase in the thickness of the generated layer, however, tends to stop at a certain maximum value in both surface modification by EDM with semi-sintered electrodes and machining of insulating ceramics by EDM processes. In these machining operations, accretion and removal phenomena occur alternately. In this paper, the mechanisms of machining insulators and the accretion process are discussed considering the characteristics of the generated layers on the work-piece surface.
Effects of Surface Roughness on Solder Bump Formation
J.-H. Chun (2), W. Hsiao  
STC E,  52/1/2003,  P.161
Keywords: Surface roughness, Precision spray deposition, Electronics
Abstract : packaging This paper presents a study of the effects of substrate surface roughness on droplet bouncing during direct solder bumping, a phenomenon that strongly affects the deposition efficiency, as well as the final bump size and shape. A theory was developed to correlate surface roughness to the potential for droplet bouncing. In addition, an experimental study was conducted by depositing Sn microdroplets on Au plated substrates with different surface roughness levels. The population densities and morphologies of the splats collected were analyzed to determine the occurrences of bouncing. The results suggest that a decreass in surface roughness reduces the potential for droplet bouncing.
Influence of electrolyte concentration on copying accuracy of precision ECM
A. De Silva (2) H. Altena (3) J. McGeough (1)  
STC E,  52/1/2003,  P.165
Keywords: ECM accuracy, Electrolyte concentration, Localised dissolution
Abstract : A precision ECM process, dimensional accuracy ±2 µm, surface finish 0.01 µm Ra, has been developed using narrow inter-electrode gaps (< 50 µm) for mass production of small (100 mm²) component parts. The electrolyte properties, especially the concentration, play a significant role in controlling the dimensional accuracy of precision-ECM. The relationships between the electrolyte concentration and various process parameters are derived empirically and are utilised in a graphical model to predict the localisation effects of electrochemical dissolution. By controlling the localisation effects significant improvements are made to the dimensional accuracy obtained. Practical examples are used to validate the model developed.
Design of Electrode Profile in Electrochemical Manufacturing Process
D. Zhu (2), K. Wang, J.M. Yang  
STC E,  52/1/2003,  P.169
Keywords: Electrode, Electro-chemical machining, Electroforming
Abstract : Accurate prediction of electrode shapes is most important in electrochemical manufacturing process which includes electrochemical machining and electroforming. In the former process, the electrode design is focused on the prediction of the cathode tool which significantly affects the machining accuracy. In the electroforming process, the anode electrode shape determines the current density distribution and so the properties of the deposited metal. This paper proposes a finite element approach to accurately determine these electrode profiles. The proposed method does not require iterative redesign process, therefore provides excellent convergence and efficient computing. Close agreements between theoretical and experimental results have been observed.
Selective laser sintering of SiC/Polyamide composites
K.K.B Hon (1), T.J. Gill  
STC E,  52/1/2003,  P.173
Keywords: Rapid Prototyping, Composite, Selective Laser Sintering
Abstract : This paper presents an experimental study into the production of particulate Silicon Carbide/ Polyamide matrix composites via the selective laser sintering (SLS) process. FEPA standard SiC grit, F240, was blended with the commercially available Duraform Polyamide to produce blend compositions of 50 volume percent and 50 weight percent SiC for direct SLS processing. A full factorial experimental approach was applied to examine the effects and interactions of laser power, scan speed, line spacing and layer thickness with regard to the mechanical and physical properties of composite sintered parts. Analysis of results and discussions of parameter interactions and individual main effects especially with regard to part strength are also presented.
Coalescence Behaviour of Two Metallic Particles as Base Mechanism of Selective Laser Sintering
F. Klocke (1), C. Wagner  
STC E,  52/1/2003,  P.177
Keywords: Laser Sintering, Metal Powder Processing, Rapid Manufacturing
Abstract : In many R&D places, the process of Selective Laser Sintering (SLS) of high performance metals is subject of investigations. An observation often made in SLS of metals is, that certain materials show a proper bonding behaviour while others tend to form welding pearls (?balling« effect). This paper aims to identify and explain process mechanisms related to this effect. The dominating physical mechanisms are investi-gated. In addition, it is described which material properties mainly affect the results. The attained insights are transferred to the conditions of SLS in a powder bed layer by process modelling and experimental testing.
Effects of Powder Geometry and Composition in Coaxial Laser Deposition of 316L Steel for Rapid Prototyping
A.J. Pinkerton, L. Li   / W.S. Lau (1)
STC E,  52/1/2003,  P.181
Keywords: Laser, prototyping, powder
Abstract : Multiple layer laser powder deposition has recently been applied to producing fully dense 3-D metallic engineering parts for rapid prototyping and tooling. To date, however, the process has been limited to using only gas-atomised, spherical powders. In this paper, the feasibility of using water-atomised powders is investigated, based on an experimental comparison of gas- and water- atomised powders in multiple layer, laser fused deposition of 316L stainless steel. The work shows that, despite much lower cost (approximately 25%37; of the price of gas-atomised powders), the water-atomised, irregular powders have superior deposition quality in terms of surface finish, deposition uniformity, microstructures and bonding between layers, compared to the gas-atomised powders under the same processing conditions, although deposition rate is lower. Powder geometry and oxygen content differences of the two powders have been found to be the principal reasons for the observed effects. Theoretical analyses of the beam-material interaction processes and melt pool behaviour are presented to explain the observed phenomena. The results indicate that there are both functional and economic reasons for using water-atomised powders for this additive manufacturing application.
Study of Part Geometric Features and Support Materials in Rapid Freeze Prototyping
M.C. Leu (2), Q. Liu, F.D. Bryant  
STC E,  52/1/2003,  P.185
Keywords: Rapid, Prototyping, Freezing
Abstract : This paper describes the investigation of part geometric features and support materials in the fabrication of ice parts by Rapid Freeze Prototyping (RFP). The achievable geometric features of the ice part including the smallest thickness of a wall and the smallest diameter of a rod are analyzed and expressed as functions of process parameters including water pressure, nozzle diameter, valve open/close frequency and duty cycle, and x-y table moving speed relative to the nozzle. The validity of the predicted results of geometric features from the analysis is verified using our experimental RFP system. In order to realize fabricating ice parts of any complex 3-D geometry, support materials are also studied. The experimental results showed a eutectic mixture of dextrose and water works well as the support material while a eutectic mixture of salt and water does not work satisfactorily.
An Investigation of the Capability Profile of the Three Dimensional Printing Process with an Emphasis on the Achievable Accuracy
D. Dimitrov, W. van Wijck, K. Schreve, N. de Beer   / J. Meijer (1)
STC E,  52/1/2003,  P.189
Keywords: Rapid prototyping, Accuracy, 3D Printing
Abstract : A benchmark procedure has been designed to assess the dimensional as well as the geometric accuracy of currently one of the most widely used rapid prototyping processes ? the Three Dimensional Printing. It tests not only linear accuracy but also precision, and repeatability of the process, as well as its ability to create manufacturing features such as fillets and draft angles. The presented research results reflect the necessity to adequately respond to engineering requirements for clearly meeting dimensional and geometric tolerances and root on several in-house case studies proving the comparison with established high-end RP processes.
Effects of Modal Interactions on Vibration Peformance in Ultrasonic Cutting
M. Lucas, A. Cardoni, F.C.N. Lim, M.P. Cartmell   / J. McGeough (1)
STC E,  52/1/2003,  P.193
Keywords: Ultrasonic cutting, Nonlinear responses, Vibration
Abstract : The effects of modal interactions and nonlinear response characteristics can hamper implementation of high power ultrasonic technologies, due to the resulting modal coupling, increased stress, audible noise levels and poor control of the operating response. These different adverse responses are illustrated by characterising the vibration behaviour of single-blade and multi-blade ultrasonic cutting systems. This paper proposes design strategies to eliminate the effects of modal interactions, by focusing on reducing the number of vibration modes, and to reduce the effects of nonlinear responses, by serial coupling of tuned components with appropriate cubic softening and hardening response characteristics.

 STC F 

A New Rolling Process for Strips With a Defined Cross Section
R. Kopp (1), P. Boehlke  
STC F,  52/1/2003,  P.197
Keywords: Forming, Rolling, Profile
Abstract : A new rolling process is being developed for producing cold rolled strips with a defined cross section. These strips feature differences in thickness up to 50%37; perpendicular to the rolling direction. A special roll system is used to achieve a material flow exclusively in the direction of the strip width. As a consequence the strip width is increased significantly. In this way a wide variety of different cross sections can be produced. The range of application for these kind of strips cover novel load-adapted and load-optimized struc-tures with different thicknesses, e.g. special profiles and special section tubes.
Development of a Highly Flexible Incremental Roll Forming Process for the Manufacture of a Doubly Curved Sheet Metal
S.J. Yoon, D.Y. Yang (1)  
STC F,  52/1/2003,  P.201
Keywords: Sheet metal, Roll, Incremental forming
Abstract : A flexible incremental roll forming process has been developed by adopting the advantages of the incremental forming process and the roll forming process: i.e., inherent flexibility of the incremental forming process and continuous bending deformation of the roll forming process. It has an adjustable roll set as a forming tool composed of one upper center roll and two pairs of lower support rolls, which plays a key role. Through the experiments, it is shown that the improved forming method of the proposed process is effective in the manufacture of various doubly curved sheet metals, and the proposed relationship of the experimental parameters and the radius of curvature of the formed sheet boundary is useful to control the final shape.
Closed loop control of the 3D bending process
K. Kuzman (3)   / M. Geiger (1)
STC F,  52/1/2003,  P.205
Keywords: 3D bending, process control, cold forming
Abstract : Mechanical properties of the incoming material have a major effect on the shape stability of 3D wire bent products. The study of the wire straightening process prior to final bending showed that it could efficiently be used to control the mechanical properties as well as straightness of the wire. The core of the stabilization algorithm is a slightly modified Prager?s flow rule considering material hardening or softening as a result of accumulated small reverse plastic strains. Flow stress calculation of the incoming material is based on the measured transverse roller forces. The obtained data define the needed repositioning of the straightening rollers. The new settings stabilize the wire material properties, which reflect in the shape of the 3D bent product.
A Geometric Approach to Modelling Friction in Metal Forming
P. Becker, H.J. Jeon, C.C. Chang, A.N. Bramley (1)  
STC F,  52/1/2003,  P.209
Keywords: Forging, Friction, Ring test
Abstract : When simulating metal forming processes it is common practice to describe the friction by using the Coulomb or Tresca model and to assume that the conditions are constant throughout the process. This paper describes an alternative approach that seeks to describe friction by modelling the geometric surface roughness of the tools. Using the ring test analytically a relationship has been established between surface geometry and the friction factor. This model has been validated experimentally also using the ring test. Such a system provides an opportunity to model friction more flexibly and accurately.
Determination of forming limit diagrams ? a new analysis method for characterization of materials´ formability
M. Geiger (1), M. Merklein  
STC F,  52/1/2003,  P.213
Keywords: Forming, Sheet Metal, Failure Criterion
Abstract : This paper introduces a new analysis method for characterization of materials´ formability independent of individual expertise. Therefore forming limit diagrams (FLDs) are determined using the Nakazima method. Investigations on the influence of the analysis method and the failure criterion in detail will be presented. The new analysis method avoids misinterpretation of the forming limits of any material and the FLD. The forming behavior of materials has to be recorded with a frequency up to 20 Hz, in order to detect the forming limits within a sequence of pictures from onset of necking to failure by cracking.
Determination of True Stress-Strain-Curves and Normal Anisotropy in Tensile Tests with Optical Strain Measurement
H. Hoffmann (2), C. Vogl  
STC F,  52/1/2003,  P.217
Keywords: Anisotropy, FEM, Tensile test
Abstract : This paper describes a method to measure the flow curve which undergoes necking and normal anisotropy as a function of equivalent strain using an optical measurement system. The flow stress was determined by modifying Siebel and Schwaigerer?s model. Normal anisotropy was regarded as a function of equivalent strain. Comparing with the experiment of the stretch forming process, the simulation using improved material properties shows the better strain distribution than the results using conventional material properties in high strain areas.
Simultaneous Determination of Flow Stress and Interface Friction by Finite Element Based Inverse Analysis Technique
H. Cho, G. Ngaile   / T. Altan (1)
STC F,  52/1/2003,  P.221
Keywords: Finite element method (FEM), Material, Inverse Analysis
Abstract : A finite element based inverse analysis technique has been developed to determine the flow stress and friction at the tool/workpiece interface simultaneously from one set of material tests. The inverse problem is aimed at minimizing the error between experimental data and predictions made by rigid-plastic finite element simulations. The ring compression test and the modified limiting dome height test (sheet blank with a hole at center stretched with a hemispherical punch) were selected for evaluating the method for bulk forming and for sheet forming, respectively. The determined flow stress data were compared with corresponding data obtained independently using the well-lubricated cylinder compression test and hydraulic bulge test. Results show that the method discussed in the study is efficient and accurate.
Development of an Optical Sensor for the Measurement of the Material Flow in Deep Drawing Processes
E. Doege (1), R. Schmidt-Jürgensen, S. Huinink, J.-W. Yun  
STC F,  52/1/2003,  P.225
Keywords: deep drawing, sensor, control
Abstract : In this paper a new optical sensor and its applications are presented. The prediction of faults that occur during the layout of deep drawing processes (e.g. cracks) remains a significant problem. Therefore, at the IFUM a new optical sensor principle has been developed for the contact-free recording of the material flow. The sensor recognizes special patterns on the sheet surface. The measured material flow can be used for the determination of local strain. The optical sensor could be utilized instead of using expensive optical systems or manual methods (e.g. with a measurement grid) for the deformation measurement, which still require a special preparation of the specimen. Furthermore, the material flow can be used as the controlled variable for the closed loop control of deep drawing processes with varying blank holder forces along the flange. On the one hand the data recorded with the new optical sensor is used to increase the quality of the FE-simulation. On the other hand a press with a multipoint drawing tool will be regulated by the control loop. A fuzzy controller is under development for the automatic connection between the material flow and the blank holding force.
Process Stability in the Tube Hydroforming Process
P. Groche, R. Steinheimer, D. Schmoeckel (1)  
STC F,  52/1/2003,  P.229
Keywords: Tube High Pressure Forming, Process Stability, Control
Abstract : Material properties have a significant influence on the process stability in tube hydroforming, particularly in series production. Mainly tubular material with longitudinally oriented welding lines is used in tube hydroforming. A new test method was developed to examine the important properties of the semi-finished product, such as flow pressure or maximum circumferential elongation during the hydroforming process. Knowing these parameters, the process control can be adjusted according to the differences of the varying semi-finished product charges. Another option to improve the process stability is a new process control strategy, which uses the volume flow instead of the conventionally used pressure as control variable. A volume control enables the production of sound parts made of different materials with varying wall thicknesses without changing the process control settings.
Homogenisation of Thickness through High Viscous Fluid Flow
F. Vollertsen (2), H. Schulze Niehoff  
STC F,  52/1/2003,  P.233
Keywords: Sheet metal, forming, flow
Abstract : This paper describes investigations on new ways to influence sheet metal forming processes through a new parameter. The new adjustable parameter is a shear stress on the surface of the sheet applied during the forming process through high viscous fluid flows. Parallel and hourglass shaped tensile test specimen were investigated, whereby a fluid flow was applied from the ends to the middle of the specimens. The results clearly show a significant influence of the high viscous fluid flows on the specimens. For the hourglass shaped specimen it could be shown that the inhomogeneous cross section distribution could be compensated by the applied shear stresses, so that a homogenous sheet thickness distribution was reached.
Multi-Stage Cold Deep Drawing of Long Pure Titanium Cups Using Coloured Sheets for Prevention of Seizure
K.I. Mori, T. Murao, Y. Harada   / T. Matsuo (1)
STC F,  52/1/2003,  P.237
Keywords: Forming, Titanium, Tribology
Abstract : Long pure titanium cups were formed by multi-stage cold deep drawing using commercial coloured titanium sheets for preventing seizing. The titanium sheets have sufficient ductility and high r-value for the deep drawing, whereas the seizure tends to occur during the deep drawing due to high reactivity with die materials. The coloured pure titanium sheets were treated by electrochemical coating so as to get oxide surface layer effective for preventing the seizing. By the use of commercial coloured sheets, the investment of coating machines can be avoided in sheet metal forming makers and the quality of the oxide layer can be controlled. The effects of the thickness of the oxide layer, die materials and lubricants on the occurrence of seizure in multi-stage deep drawing were examined. It was found that the coloured pure titanium sheets have sufficient ability in preventing the seizure in multi-stage deep drawing processes.
Pneumatic Bulging of Magnesium AZ 31 Sheet Metals at Elevated Temperatures
K. Siegert (1), S. Jäger, M. Vulcan  
STC F,  52/1/2003,  P.241
Keywords: Magnesium, Pneumatic, Sheet metal
Abstract : This paper deals with forming magnesium sheet metal components like auto body parts by pneumatic bulging. Furthermore, this paper deals with the evaluation of true stress-true strain curves as well as with forming limit curves determined by pneumatic bulging at temperatures up to 350°C. It can be shown that magnesium AZ31 is quite good formable at temperatures in the range of 250°C to 350°C. Outgoing from these fundamental investigations, an auto body sheet metal component was formed by pneumatic bulging at a temperature of about 300°C. Furthermore, the strains over the component were measured with an automated grid analysis. This analysis shows a nearly equal distribution of the strains over the component.
Reduction of blanking noise by controlling press motion
M. Otsu, C. Yamagata, K. Osakada (1)  
STC F,  52/1/2003,  P.245
Keywords: Blanking, Noise, Press Motion
Abstract : To reduce blanking noise with servo controlled presses, continuous two steps blanking, in which the punch is stopped at an intermediate position before breakthrough and soon moved again to finish the process, is proposed. Plates of carbon steels, 18-8 stainless steel, titanium and copper are tested. When the punch is stopped just before breakthrough, the noise can be reduced to a very low level especially for high strength carbon steel plates. The mechanism of noise reduction in the process is clarified through the measurement of sound wave and machine vibration together with short-time FFT analysis.
On the use of SLS Tools in Sheet Metal Stamping
G.N. Levy (1), R. Schindel, p. Schleiss, F. Micari (2), L. Fratini  
STC F,  52/1/2003,  P.249
Keywords: Rapid, Tooling, Wear
Abstract : A few rapid tooling technologies have been recently proposed and among them Selective Laser Sintering is probably one of the most relevant and promising. In the paper, the authors report some results of a wide experimental research on the application of SLS tools in sheet metal forming. A wear test was carried out to investigate the progressive degradation of laser-sintered materials in comparison with traditional cold-work steels. In particular SLS tools were utilized in a sheet metal stamping process of S-shaped parts: their performances (in terms of tool wear and dimensional quality of the stamped part) were compared with the ones of traditional tools.

 STC G 

Chip Formation Mechanisms in Grinding at Low Speeds
E. Brinksmeier (1), A. Giwerzew   
STC G,  52/1/2003,  P.253
Keywords: Grinding, Chip Formation, Cutting Speed
Abstract : Grinding processes characterised by cutting speeds as low as 0.3...5 m/s are becoming more and more important amongst abrasive technologies for finishing of hardened gears. A number of research work carried out in this area in the past few years has significantly improved the understanding of common technological interdependencies. However, there is still a lack of knowledge about the main chip formation mechanisms at such low speeds. In order to investigate these mechanisms, single grit scratching tests and grinding experiments have been performed. The cutting speed and the chip thickness were identified as main quantities determining the chip formation process. These results can be used for design of grinding processes and development of suitable abrasive tools.
Optimization of Continuous Dress Creep-Feed Form Grinding Process
C. Guo (3), M. Campomanes, D. McIntosh (3), C. Becze, T. Green   / S. Malkin (1)
STC G,  52/1/2003,  P.259
Keywords: Grinding, Nickel Alloy, Optimization
Abstract : This paper is concerned with optimization of continuous-dress creep-feed grinding processes to reduce cycle time and wheel consumption by adaptively adjusting workspeed and dress infeed based on grinding models and in-process power monitoring. Heat flux is kept below the fluid burnout limits to avoid thermal damage to the ground surface. Grinding forces are controlled below the allowable values to avoid coating cracks caused by excessive strain on the blade. By implementing this approach, 40%37; cycle time reduction was demonstrated while maintaining the heat flux and grinding forces below their allowable critical values.
Temperatures in Grinding of Magnetic Composites - Theoretical and Experimental Approach
B.W. Kruszynski (2), J. Pazgier  
STC G,  52/1/2003,  P.263
Keywords: Grinding, Thermal Model, Magnetic Composite
Abstract : The present paper is concerned with grinding temperatures and surface integrity for grinding of magnetic composites consisting of sandwich-like layers of brittle magnetic material and soft steel. High temperatures which are generated during grinding of these magnetic composites may have a detrimental effect on their magnetic properties if the grinding temperature exceeds the Curie point of the magnetic component. A thermal model was developed to calculate the grinding temperatures in the magnetic composite workpiece. Temperatures measured in the magnetic composite using embedded thermocouples were found to be consistent with predictions from the thermal model. Crucial regions in the magnetic composite were found where the highest temperatures and temperature gradients occur and where surface integrity may be destroyed. The range of grinding conditions providing both high efficiency and good surface quality were found.
An Investigation of Grinding with Electroplated CBN Wheels
Z. Shi, S. Malkin (1)  
STC G,  52/1/2003,  P.267
Keywords: Grinding, Cubic boron nitride (CBN), Wear
Abstract : Grinding of hardened bearing steel with electroplated CBN wheels was investigated with particular attention to how the wear of the abrasive grains affects the wheel topography and grinding performance during the wheel life. Power, surface roughness, and wheel topography data were obtained throughout the wheel life for internal cylindrical grinding. Dulling of CBN grains by attrition was found to cause an increase in the grinding power, but the degree of dulling was restricted mainly by grain fracture and also by grain pullout. Grain fracture and pullout had a much smaller effect on the progressive increase in active grain density, which caused the surface roughness to progressively decrease. Wheel failure tended to occur by stripping of the abrasive layer when the radial wear reached about 70%37; ? 80%37; of the grain dimension
Surface Generation with Engineered Diamond Grinding Wheels: Insights from Simulation
P. Koshy, A. Iwasaki, M.A. Elbestawi (1)  
STC G,  52/1/2003,  P.271
Keywords: Grinding, Roughness, Simulation
Abstract : Engineered wheels are a recent innovative development towards consistent and exceptional performance in fine grinding operations. Abrasive grains in an engineered wheel are positioned in a specific spatial pattern, as opposed to random locations in a conventional wheel. The present work relates to the formulation of a theoretical framework for the design of engineered wheels in terms of maximizing their performance with respect to their surface generation characteristics. Computer simulations indicate that: (i) The distribution of abrasive protrusion height, rather than its absolute maximum value, determines the roughness of the ground surface and controls the associated variability, and therefore by tailoring the distribution appropriately, the performance of the wheel can be improved significantly, (ii) With an ordered arrangement of abrasive grains, the finish obtained is a strong function of the axial offset between adjacent rows of grains, but the best finish achieved thus is only on the order of that obtained with a conventional wheel, and (iii) The effect of grain shape on the roughness of the ground surface is comparable to the inherent process variability.
Development of a Superabrasive Grinding Wheel with Defined Grain Structure Using Kinematic Simulation
J.C. Aurich, O. Braun, G. Warnecke   / L. Cronjäger (1)
STC G,  52/1/2003,  P.275
Keywords: Grinding, Simulation, Superabrasive Tool
Abstract : This paper presents the concept of superabrasive electroplated grinding wheels based on defined grain structures. The aim is to improve process stability, minimize heat generation and achieve a high surface quality while preserving a high material removal rate. Based on geometrical models, different patterns of grit settings have been investigated by means of kinematic simulation. Applying the results of the simulation, a prototype grinding wheel with an optimized defined grain structure has been constructed. The performance potential of the prototype has been analyzed through experimental examinations.
Development of a High-Speed Manufacturing Method for Electroplated Diamond Wire Tools
Y. Chiba, Y. Tani (2), T. Enomoto, H. Sato (1)  
STC G,  52/1/2003,  P.281
Keywords: Grinding, Wire Tool, Electroplating
Abstract : Fixed-abrasive multi-wire sawing processes can be used to slice silicon and quartz crystal due to the introduction of resinoid diamond-wire or electroplated diamond-wire tools. The latter kind have a higher wear resistance, but have higher production costs because electroplating is time consuming. Consequently, it is impractical to use them because they are too expensive. In this paper, ultra high-speed electroplating using felt brushes is proposed for manufacturing them. A series of experiments revealed that production speed is improved 30 times and tools produced with the new process have a higher wear resistance than commercially produced tools.
Lapping of single crystal diamond tools
Z.J. Yuan (1), Y.X. Yao, M. Zhou, Q.S. Bai  
STC G,  52/1/2003,  P.285
Keywords: Diamond, Lapping, Crystal plane
Abstract : Lapping is the key technology used in manufacturing process of diamond tools and diamond jewels. Because of the strong anisotropism and super hardness of diamond, the material removal rate is very small in its lapping process. The influence of the crystal anisotropism on removal rate in diamond lapping is discussed in this paper. A new diamond crystal orientation method by using laser diffraction is presented, which can not only be used for the crystal orientation, but also for the indication of ?soft? directions on crystal planes in lapping. The mechanism of removal rate anisotropism in diamond lapping is investigated, and a new explanation for the reasons is proposed. It is pointed out that the variation of inclination angle between inside (111) plane (cleavage plane) and lapping surface causes the difference of friction coefficient and removal rate in diamond lapping. Furthermore, a new method using ultrasonic vibration for diamond lapping was developed to improve the removal rate.

 STC M 

Ferraris Sensor - The key for advanced dynamic Drives
G. Pritschow (1), C. Eppler, W.-D. Lehner  
STC M,  52/1/2003,  P.289
Keywords: Control, Drive System, Acceleration Sensor
Abstract : The positioning features of feed drives in machine tools are nowadays almost always guaranteed by a proportional positioning and a proportional and integral velocity controller with an underlying fast current controller. The achievable dynamics of the positioning control are mainly determined by mechanical oscillations within the structure. In this paper it is shown that the bandwidth of the positioning and velocity controller depends also on the acquisition of the state variables. New methods for measuring the relative acceleration according to the Ferraris principle guarantee a velocity of low quantization together with a conventional cascade control. Based on these improvements it is shown that an underlying acceleration control can increase the dynamic disturbance stiffness further. This requires new control structures. Measuring results of single drive systems and a milling operation with a 5-axis machine tool have shown what potential lies in the improved acquisition of state variables by a relative acceleration sensor to achieve highly dynamic and accurate machining results.
Robustification of CNC Controllers for Machine Tools Motor Drives
P. Boucher (2), D. Dumur (1), P. Rodriguez  
STC M,  52/1/2003,  P.293
Keywords: Control, machine tool, drives
Abstract : This paper presents a methodology for enhancing the robustness of a CNC controlled system by convex optimisation of the Youla parameter. The methodology requires as a first step the design of an initial polynomial controller. This controller is then robustified considering temporal and frequency constraints, which are formulated by means of the Youla parameterisation within a convex optimisation framework. The optimal Youla parameter is finally obtained by solving this optimisation problem. In this way, a compromise between robustness and closed loop behaviour can be easily managed. An application to the position control of an induction motor drive is presented, where the robustness of different controllers (PID or GPC) regarding model uncertainties in high frequency is enhanced while respecting a temporal template for the disturbance rejection.
Feedrate Optimization for Spline Interpolation in High Speed Machine Tools
Y. Altintas (1), K. Erkorkmaz  
STC M,  52/1/2003,  P.297
Keywords: Spline, CNC, Interpolator
Abstract : A feedrate optimization technique has been developed for minimizing the cycle time in machining spline toolpaths. Axis velocity, torque and jerk limits are considered throughout the motion in order to ensure smooth and linear operation of the servo drives with minimal tracking error. Feed modulation is achieved by manipulating segment durations which define the overall minimum jerk feed profile. Long toolpaths are handled by applying a windowing technique. The optimized feed profile allows nonzero acceleration and jerk values at segment connections, resulting in continuous and smooth motion within the velocity, torque, and jerk limits of the drives. The cycle time reduction obtained with the proposed technique is demonstrated in high speed contouring experiments.
Sensor-less Monitoring of Cutting Force during Ultraprecision Machining
H. Shinno (2), H. Hashizume, H. Yoshioka  
STC M,  52/1/2003,  P.303
Keywords: Ultra-precision machining, In-process monitoring, Cutting force
Abstract : Future ultreprecision machining systems will require intelligent machine tools equipped with effective systems for in-process monitoring of machining status. To meet the requirement, much attention has been directed to the monitoring method of cutting force, temperature, acoustic emission, etc. Cutting force includes useful information on machining status, however it is difficult to apply these methods for an ultraprecison machining environment. In this paper, a sensor-less monitoring method has been proposed based on a new concept. In the proposed method, a disturbance observer is installed in the position controller for a linear motor-driven aerostatic table system. The performance of the monitoring system has been evaluated through a series of ultraprecison machining experiments.
An Optimized Design of the Bearing in Machines for Ultrasonic Machining Processes
U. Heisel (1), D. Klotz  
STC M,  52/1/2003,  P.307
Keywords: Ultrasonic manufacturing, bearing, vibration insulation
Abstract : In high-power ultrasonic manufacturing processes, the design of the bearing of the components transmitting ultrasound is of particular importance, since the position of the nodal planes in the vibrating structure is altering as a consequence of changing coupling conditions during the process. A special bearing, which reduces the residual vibrations at the fixing ring by a system of several resonators, has been developed for the use in ultrasonic production processes, such as tube drawing and wire drawing but also drilling and welding. Since the transmitted longitudinal vibrations always involve radial components as well, the dynamic stiffness of the coupling on the interface between the components transferring energy and the components deleting vibration is very important. In the method described in this paper, an optimization of dynamic behavior is attained by stiffness-reduced coupling.
3- and 4-Contact Point Spindle Bearings - a new Approach for High Speed Spindle Systems
M. Weck (1), G. Spachtholz  
STC M,  52/1/2003,  P.311
Keywords: Spindle system, Ball bearing, High Speed
Abstract : One important demand on spindle systems in modern machine tools is to realise higher rotational speeds in order to increase the machining efficiency. In conventional spindle bearings the contact angles on inner and outer ring deviate extremely from one another with rising rotational speeds due to centrifugal forces. Axial shift of the inner ring (elastic mounted bearing) and increasing normal forces in the contact zones on the outer ring are typical consequences leading to high internal bearing loads and a reduced life span. Based on these problems bearings with a new inner geometry are studied. Instead of two contact zones these bearings have three or four contact zones to ensure constant contact angles and reduced normal forces on the outer ring. In this paper analytic operation studies and first experimental tests are presented.
A nanometre-precision, ultra-stiff piezostepper stage for ELID-grinding
H. Van Brussel (1), D. Reynaerts, p. Vanherck (1), M. Versteyhe, S. Devos  
STC M,  52/1/2003,  P.317
Keywords: Positioning, piezoelectric, ultra-precision
Abstract : The extremely high machine stiffnesses required for a successful implementation of ELectrolytic In-process Dressing (ELID) grinding cannot be obtained with conventional technologies. In this paper, an innovative drive concept is presented, where the actuation and guiding functions in three degrees of freedom are combined in one functional unit, using an original piezo-stepping technology. The stage is actively positioned by a set of six ?feet? giving it an infinite static stiffness in all six degrees of freedom. The drive motions in x-, y- and C-directions are obtained by rolling the feet over the base surface in a three-by-three feet gait pattern. The stepping resolution can be as low as 2.5 nm. Hammering is avoided by force-controlled stepping. The x and y stage positions are interferometrically measured. Thermal errors are minimised by a symmetrical design.
Development of a 9 Axes Machine Tool for Bone Cutting
M. Mitsuishi (2), S. Warisawa, F. Tajima, M. Suzuki, K. Tanimoto, K. Kuramoto  
STC M,  52/1/2003,  P.323
Keywords: Machine Tool, CAD/CAM, Biomedical Application
Abstract : The femur and the tibia must be shaped to ensure that they are fit firmly to an artificial joint in total knee joint replacement. The normal procedure is to manually cut the bones using a bone saw and mechanical jigs. A 9 axes bone cutting machine tool has been developed by the authors to increase cutting accuracy and reduce the hospital stay required for recuperation. As developed, the cut plane is determined by a 5 degree-of-freedom mechanism and the femur and tibia are cut by moving two translational and one rotational degrees of freedom to avoid the ligament. Preoperative planning system as a CAD/CAM system and overview of the assisting system for total knee arthroplasty are also discussed. Experimental results for bone cutting are presented.
Assessment of Force-Induced Errors in CNC Turning
S. Hinduja (1), D. Mladenov, M. Burdekin  
STC M,  52/1/2003,  P.329
Keywords: CNC turning, force-induced errors, spindle-bearing system
Abstract : This paper describes a procedure to evaluate the force-induced errors occurring in cylindrical turned components. This procedure is based on a model which represents the real-time stiffness of the spindle-bearing system and the rotational clamping stiffness of the component held in a chuck. The stiffness values are determined from a single cutting test in which the deflection of a test bar is measured. The model also takes into account the stiffness of the component and toolpost. The model is validated by comparing the predicted error in the cylindricity of a machined bar with the measured value.
Assessing Thermally Induced Errors of Machine Tools by 3D Length Measurements
G.H.J. Florussen, F.L.M. Delbressine (2), P.H.J. Schellekens (1)  
STC M,  52/1/2003,  P.333
Keywords: Machine tool, Thermal error, Measuring instrument
Abstract : A new measurement technique is proposed for the assessment of thermally induced errors of machine tools. The basic idea is to measure changes of length by a telescopic double ball bar (TDBB) at multiple locations in the machine?s workspace while the machine is thermally excited. In addition thermal machine error models are verified and optimised by comparing measured and predicted TDBB length deviations. Validation measurements reveal that more than 60 %37; of the thermally induced errors can be described by the thermal machine error model proposed at any time and at any position in the machine?s workspace
Kineto-static Optimisation of PKMs
L. Molinari-Tosatti (2), I. Fassi, G. Legnani  
STC M,  52/1/2003,  P.337
Keywords: Parallel Mechanism, Performance index, Isotropy.
Abstract : One of the main drawbacks of PKMs is the non uniformity of force and velocity transmission and stiffness characteristics in the workspace. This non uniformity can be dramatically reduced and in some cases, but the case of 6 dof PKMs, even eliminated using efficient kineto-static optimization criteria in the design phase. In this paper new performance indexes for the optimisation of 6 dof fully parallel PKMs, developed by the authors, are presented. These indexes overcome the fact that the Jacobian matrix J is not consistent in units and allow an independent study of the linear and the angular behaviour of the machine. The well known octahedron proposed by Duffy is analysed using the new indexes. The first Italian PKM for 5 axis milling operations ? Celerius ? developed by ITIA-CNR using an optimisation criteria based on the presented indexes is introduced. This machine exhibits an isotropic behaviour in the middle of its workspace and is almost isotropic in all the other points of the useful workspace.
Workspace Enlargement for Parallel Kinematic Machines
J. Hesselbach, M. Helm   / H. Kunzmann (1)
STC M,  52/1/2003,  P.343
Keywords: Kinematic Design, Robot Control, Singularity
Abstract : The paper presents an approach that allows parallel kinematic machines to move through singular poses typically connected with them. Using this the usable workspace of parallel kinematic machines can be significantly increased. This compensates the main disadvantage of parallel kinematic machines, i.e. the sometimes poor ratio of workspace to machine size. Their main advantage, the higher structural stiffness, is maintained. To efficiently apply this to the kinematic design of production machines, different types of workspaces are defined. Finally a robot is presented that passes through singular poses and shows the possibilities in increasing machine performance by applying the presented method.
Design of a Parallel Mechanism Platform for Simulating Six Degrees-of-freedom General Motion Including Continuous 360-degree Spin
J. Kim, Y.M. Cho, F.C. Park, J.M. Lee (1)  
STC M,  52/1/2003,  P.347
Keywords: Parallel mechanism, Kinematic design, Motion simulation
Abstract : This paper presents a new six degree-of-freedom parallel mechanism platform, which can be used as a basis for general motion simulators. The unique feature of the platform is that it enables unlimited continuous 360-degree spin in any rotational axes plus finite X, Y, and Z-axis translation motion. The first part of the paper deals with the kinematic design issue of the platform including singularity avoidance problems. The second part describes the design and development issues of the working sample structure. It has been assembled and tested successfully to verify the original idea of general motion simulators. For demonstration purposes, the real motions of the platform are synchronized with those of the real roller coaster in operation, whose path contains several overturning pitching and rolling loops.

 STC O 

Process management for engineering environments based on dynamic process modeling
R.J. Mentink, F.J.A.M. van Houten (1), H.J.J. Kals (1)  
STC O,  52/1/2003,  P.351
Keywords: Engineering, Process management, Information management
Abstract : The research presented in this paper proposes a concept for dynamic process management as part of an integrated approach to engineering process support. The theory of information management is the starting point for the development of a process management system based on evolution of information content. The use of an ontology enables the formalization of information content. Based on this ontology, transition relations and task definitions can be instantiated. A methodology for the generation of task networks is presented. From these networks, process models can be derived in the form of task chains.
Design and Analysis of a Closed-Loop Single-Workstation PPC System
A.M. Ratering, N.A. Duffie (1)  
STC O,  52/1/2003,  P.355
Keywords: Production, Control, Analysis
Abstract : Methods of control engineering can be integrated with methods of production engineering to improve robustness and performance of production systems, while making dynamic analysis tractable and improving understanding of complex behavior. In this paper a discrete, dynamic model of a single workstation is developed, including characteristic equations of transfer functions that are useful in choosing control parameter values according to desired dynamic performance and response. Nonlinearities such as dependence of capacity on WIP and delay in adjusting capacity due to work rules are modeled and incorporated into the dynamic analysis. Examples are presented of control parameter selection and resulting performance.
Project Scheduling Approach to Production Planning
A. Markus (2), J. Vancza, T. Kis, A. Kovacs  
STC O,  52/1/2003,  P.359
Keywords: production, planning, project
Abstract : We suggest a novel approach to modelling and solving production planning (PP) problems in make to order production environments. This approach unifies the capacity and the material flow oriented aspects of PP. Orders are modelled as projects that compete for limited resources. The projects consist of networks of variable-intensity activities which may require several resources at the same time. The goal is to generate production plans that satisfy all the temporal and resource constraints and minimize additional or external resource usage over the planning horizon. The model is applicable at different aggregation levels of PP, as we show with two real-life case studies. Although the capacity and material flow aspects of PP are coupled, a special solver developed for the project model efficiently solves problems of real-life sizes.
Modelling of Manufacturing Systems Complexity
W.H. ElMaraghy (2), R.J. Urbanic  
STC O,  52/1/2003,  P.363
Keywords: Product, Process, Man-Machine Systems, Manufacturing
Abstract : This research aims at understanding the effects of human worker attributes within the manufacturing system. The system must balance human characteristics, needs, skills and capabilities within the technical and business environment, in order to be effective. A model is needed to provide insights into the sensitivities of the manufacturing system. A methodology to systematically determine the product and process complexity for any manufacturing environment was introduced ? a rapid Manufacturing Complexity Assessment Tool (MCAT). The complexity model is based on three elements: total quantity of information, diversity of information and the information content which corresponds to the effort to produce a feature within a product. Product and process complexity are decoupled and treated independently in this analysis. An example is presented to illustrate the methodology for both. The purpose is to develop a tool that helps to identify areas of complexity that can be simplified.
Convertibility Measures for Manufacturing Systems
V. Maier-Speredelozzi, Y. Koren (1), S.J. Hu  
STC O,  52/1/2003,  P.367
Keywords: Manufacturing system, Performance analysis, Convertibility
Abstract : With increased consumer demands for a wider variety of products in changeable, unpredicted quantities, manufacturing system responsiveness has become increasingly important for industry competitiveness. Manufacturers need systems that can be rapidly adjusted with regard to both functionality and throughput capacity over the lifetime of the system. Convertibility is defined as the capability of a system to adjust production functionality, or change from one product to another. End-users of manufacturing systems are struggling with the issue of how to measure and quantify convertibility. Metrics for convertibility are proposed in this paper so that different manufacturing systems can be compared with respect to this area of performance. These metrics are based on assessments of the configuration itself, and the system components such as machines and material handling devices. Metrics for quantifying convertibility are useful for comparing system configurations during the early phases of design, without requiring detailed product or process plan information.
Stochastic Optimal Capacity Management in Reconfigurable Manufacturing Systems
F.M. Asl, A.G. Ulsoy (2)  
STC O,  52/1/2003,  P.371
Keywords: Reconfigurable Manufacturing Systems, Capacity Management, Optimization, Feedback Control
Abstract : This paper presents an optimal policy, based on Markov decision theory for the capacity management problem in a firm facing stochastic market demand. The firm implements a reconfigurable manufacturing system and faces a delay between the times capacity changes are ordered and the times they are delivered. Optimal policies are presented as optimal boundaries representing the optimal capacity expansion and reduction levels. To increase the robustness of the optimal policy to unexpected events, the concept of feedback control is applied to address the capacity management problem. It is shown that feedback provides sub-optimal solutions to the capacity management problem which are more robust under unexpected disturbances in market demand and unexpected events.
A Systematic Approach for Ensuring the Logistic Process Reliability of Supply Chains
H-P. Wiendahl (1), G. von Cieminski, C. Begemann  
STC O,  52/1/2003,  P.375
Keywords: Optimisation, Production, Management
Abstract : In the production logistics context, the process reliability of supply chains corresponds to their ability to meet the logistic performance expectations of customers. This ability depends on the contributions of all supply chain members to the logistic performance of the entire chain. The overall performance is affected by the dynamic interrelationships between the specific logistic performances of the separate supply chain members. Currently, however, no practical analytical models of the logistic supply chain dynamics are available. This paper presents an approach for modelling and analysing the logistic interdependencies across supply chains, the understanding of which enables supply chains to better control their process reliability.
Decision Making in Logistics: A Chaos Theory Based Analysis
S.R.T. Kumara (1), P. Ranjan, A. Surana, V. Narayanan  
STC O,  52/1/2003,  P.381
Keywords: Non-linear dynamics, Production, Distributed.
Abstract : Logistics in general is a complex system. In this paper we investigate the existence of chaos in logistics systems. Such an investigation is necessary to use appropriate and correct methods for further analysis, as linear systems techniques will not be useful. If a system exhibits chaos, decision-making should consider the system characterization parameters from a chaos theory perspective. In this paper, we consider a non-preemptive queuing model and its extensions to the logistics domain. A prototypical supply chain example is used and the resulting behavior is characterized. At certain input values the behavior of the logistics system exhibits chaos. This information is useful for further analysis for prediction and control. The working prototype is implemented in the DARPA Couggar agent architecture.
Using Fuzzy Multi-Agent Decision-Making in Environmentally Conscious Supplier Management
H.C. Zhang, J. Li   / M.E. Merchant (1)
STC O,  52/1/2003,  P.385
Keywords: Environmental Impact, Fuzzy Simulation, Multi-Criteria Decision Making
Abstract : Abstract Integrating environmental issues into supplier management is a challenge to manufacturers. Environmental performance is hard to quantify and difficult to compare with other criteria such as price and quality. This paper proposes a fuzzy multi-agent decision-making strategy to facilitate supplier management. A fuzzy model is used to evaluate the environmental performance of the suppliers and the life cycle environmental impact of the purchased product. Through analyzing manufacturer?s business strategy, combined with other decision parameters, an optimal supplier is selected under fuzzy multi-criteria decision analysis.
A Novel Digital Enterprise Technology Framework for the Distributed Development and Validation of Complex Products
P.G. Maropoulos (2), B.C. Rogers, p. Chapman, K.R. McKay, D.C. Bramall  
STC O,  52/1/2003,  P.389
Keywords: Distributed Design Manufacturing Integration, Measurement Planning
Abstract : The development of complex products involves considerable risk in terms of meeting target delivery dates, controlling life-cycle costs and establishing an efficient production network. This paper describes a new methodology for complex product design and development that utilises the recently proposed framework of ?Digital Enterprise Technology? (DET). The methodology involves utilising the five technical strands of DET and in particular focuses in developing novel methods and tools for aggregate modelling, knowledge management and laser measurement planning to ?bridge? the gap that exists between conceptual product design and the organisation of the corresponding manufacturing and business operations. A pilot system has been created for simulating the distributed development and validation of complex aerospace products.
Collaborative Production on the Basis of Object Oriented Software Engineering Principles
G. Schuh, M. Bergholz   / E. Westkämper (1)
STC O,  52/1/2003,  P.393
Keywords: Factory, Design, Network
Abstract : One of the main challenges for production enterprises is succeeding in the dynamic competitive environment with its rapidly changing requirements. A strategy for the individual factory to cope with these turbulent market and technological developments is to focus itself on a specific set of competencies and capacities and to offer these within the framework of temporary production networks which can be rapidly configured to meet changing requirements. Therefore, the individual factory must be able to integrate itself into temporary partnerships for changing production tasks but at the same time retain a stable basis for the efficient utilisation and sustainable development of its own capacity and competence. The developed object oriented explanation model is based on object oriented software engineering principles and describes an approach for the initial configuration and reconfiguration of factories within the framework of collaborative production networks.
Negotiation mechanisms for capacity allocation in distributed enterprises
M. Bruccoleri , G. Lo Nigro , F. Federico , S. Noto La Diega (1), G. Perrone (2)  
STC O,  52/1/2003,  P.397
Keywords: Computer aided planning, distributed manufacturing, multi-agent system
Abstract : The paper proposes an agent based approach for the capacity allocation in distributed enterprises, char-acterized by complex and articulated organizations and by geographically distributed production capaci-ties contended by many product families. In such a scenario the process of allocating the production ca-pacity to the single customer order is one of the major bottlenecks of the production planning activity as far as many organizational decisional levels are involved and market turbulence implies a continuous re-tuning of the capacity allocation plan. A high grade of reactiveness is needed. Agent based approaches and negotiation models, by decentralizing the decisional control and simplifying the decision itself, make the capacity allocation process enough reactive. Although, when the actors involved in the negotiation have different decisional powers and different knowledge, the problem of decentralization and specifically the design of the negotiation mechanism become very complex. This paper proposes two negotiation models for the capacity allocation process in distributed enterprises. The models, rationalised by using the standard IDEF3 representation, have been tested in the industrial environment of a primary semicon-ductor company.
Disassembly Scheduling with Multiple Product Types
H.-J. Kim, D.-H. Lee, p. Xirouchakis, R. Züst (1)  
STC O,  52/1/2003,  P.403
Keywords: Disassembly, Production Planning and Scheduling, Optimization
Abstract : We consider the problem of determining the disassembly schedules of used products while satisfying the demand of their parts/components over a planning horizon. The case of multiple product types with parts commonality is considered for the objective of minimizing the sum of setup, disassembly operation, and in-ventory holding costs. A heuristic algorithm is proposed using the linear programming relaxation approach. Test results of the case study on the data obtained from a disassembly shop show that the heuristic algorithm suggested in this paper works well for practical problems.
Grinding Wheel Management through Neuro-Fuzzy Forecasting of Dressing Cycle Time
R. Teti (2), D. D'Addona  
STC O,  52/1/2003,  P.407
Keywords: Tool management, Grinding Wheels, Neuro-fuzzy system
Abstract : A multiple supplier tool management system based on reliable tool delivery forecasting is developed for optimum tool inventory sizing. The system is built up on the basis of historical data on tool management comprising the series of tool shipment and delivery dates between one manufacturing company and several external tool manufacturers in a supply network. If historical data are highly variable due to the incidence of uncertain but not random factors, classical time series analysis cannot measure the imprecision deriving from events that are neither stochastic nor casual. An alternative is given by the analysis through intelligent computing techniques capable to deal with deterministic events but also take into account unpredictable factors for better results in prediction and forecast. A neuro-fuzzy system is used in this paper to approach optimum tool inventory sizing of CBN grinding wheels for nickel base alloy turbine blade fabrication.
Computer-Aided Planning of Laser Scanning of Complex Geometries
H. ElMaraghy (1), X. Yang   
STC O,  52/1/2003,  P.411
Keywords: Computer-Aided Planning, Inspection and Quality
Abstract : A computer-aided planning method for laser scanning based on the CAD model has been developed. It integrates three planning criteria, visibility, accuracy, and efficiency and detects deep concave features that would be more suitable for CMM probing. Clustering, based on the view angle and depth of view, is used to plan an optimal scanner placement and motion path. Simulation studies on complex auto-parts demonstrate the effectiveness of the generated plans. The integration of the scanning plan with CMM controls was also demonstrated. The benefits of the CAD-based automated laser inspection planning have been demonstrated.
Designing a Turbine Blade Cooling System Using a Generalised Regression Genetic Algorithm
R. Roy, A. Tiwari, J. Corbett (1)  
STC O,  52/1/2003,  P.415
Keywords: Design, Optimisation, Artificial Intelligence
Abstract : The design of a turbine blade cooling system is a multi-objective optimisation problem involving constraints and complex interaction among its design variables. The aim of this paper is to develop a methodology to optimise this design using Evolutionary Computing techniques. This paper presents Generalised Regression Genetic Algorithm (GRGA) and the mathematical model of a real-life turbine blade cooling system. Even in the presence of variable interaction, the methodology identifies a number of good feasible designs from which one could be finally chosen based on designer?s preferences. The research also demonstrates that GRGA is capable of optimising a real-life design.
Automation of the Powder-Injection-Moulding Process for Micro-Mechanical Parts
J. Fleischer , C. Buchholz, H. Weule (1)  
STC O,  52/1/2003,  P.419
Keywords: Automation, Micro production, Powder Injection Moulding
Abstract : Powder-Injection-Moulding (PIM) offers a high potential for the fabrication of micro-mechanical parts manu-factured in wear-resistant materials like metal or ceramics. To ensure an economic micro-PIM production in large lot sizes and high quality, automation of the process is a necessity. Within the field of automation research it is of utmost importance to set up correlations between producible sizes, microstructure geome-tries, the demoulding capability and the separation of microstructures from sprues. The paper presents an approach of a closed automated process chain with the focus on the demoulding, separation and handling of fragile micro parts. The process is built up on moulded toothed wheels with diameters of less than 1400 µm.

 STC P 

Uncertainties in CMM Measurements, Control of ISO Specifications
J.M. Sprauel, J.M.. Linares, J. Bachmann, p. Bourdet (1)  
STC P,  52/1/2003,  P.423
Keywords: Coordinate measuring machine, Uncertainty, Statistical
Abstract : In the scope of quality control, accurate evaluation of measurement uncertainties is a real challenge to im-prove the use of Coordinate Measuring Machines (CMM). In our work, a new method, based on a statistical approach of the problem, was therefore developed, to deduce instantaneous measurement uncertainties di-rectly from the set of acquired coordinates. The covariance matrix of the intrinsic parameters which charac-terize each analyzed surface is also evaluated, thus allowing an accurate propagation of the measurement uncertainties to the ISO specifications to be controlled. The experiments carried out in our study illustrate this new statistical approach and demonstrate its relevance.
A Study on the Optimal Design of Laser-based Multilateration System
G.X. Zhang (1), X.H. Li, Y.B. Lin, S.G. Liu, X.L. Liu, X.F. Li, J.B. Guo, Z.R. Qiu, S.Z. Zhao, C.Z,   
STC P,  52/1/2003,  P.427
Keywords: Measurement, Optimization, Flexible Coordinate Measuring System
Abstract : A flexible coordinate measuring system based on multi-lateration with tracking laser interferometers has been built. The problems related to the optimal design of the system are studied. The principle of redundancy and its application in self-calibration, error compensation, system optimization, lost information recovery, and measuring range extension are discussed. A new tracking system with independent drives and a new design of the cat?s eye are proposed. The optimal arrangement of the multi-lateration system, which is essential for improving its accuracy, is studied in detail. All the studies combine computer simulations and experiments.
Strain-tuning of Optical Devices with Nanometer resolution
S.G. Kim (2), C.W. Wong, Y.B. Jeon  
STC P,  52/1/2003,  P.431
Keywords: Optical, Nanometer resolution, Strain-tuning
Abstract : We stretched diffractive gratings by thin-film piezoelectric actuators, and demonstrated observable changes in grating period with sub-nanometer resolution. Characterization of fabricated MEMS devices suggests that strain-tuning can be widely used to make silicon optical devices tunable. Due to the virtual absence of electro-optic and charge carrier effects in silicon, thermo-optics has been the only means so far to achieve tunability. Mechanical strain-tuning would provide a faster response time, a lower power consumption and better localization of tunability, permitting fine tuning to fabrication mismatches, and active compensation to external disturbances. A first tunable microcavity photonic crystal is developed with a maximum strain of 0.21%37; to achieve 12 nm tuning of the resonant wavelength for C-band optical signals.
Precision Measurement of Two-Axis Positions and Tilt Motions
W. Gao, S. Dejima, Y. Shimizu, S. Kiyono   / H. Yoshikawa (1)
STC P,  52/1/2003,  P.435
Keywords: Metrology, Sensor, Positioning
Abstract : A prototype surface encoder consisting of a sinusoidal angle grid and a two-dimensional slope sensor is developed for two-axis position measurement. The angle grid has a three dimensional micro-structured surface, which is a superposition of periodic sinusoidal waves in the X- and Y-directions with spatial wavelengths of 150 µm and amplitudes of 100 nm over an area of up to 150 mm in diameter. The laser-based slope sensor is used to read local slope profiles of the grid surface. The X- and Y-positions together with tilt motions about the X-, Y- and Z-axes can be detected with resolutions of 0.1 µm and 1 arc-second through scanning a multi-spot laser beam across the grid surface at a constant speed.
Laser Polarization State Measurement in Heterodyne Interferometry
D.J. Lorier, B.A.W.H. Knarren, S.J.A.G. Cosijns, H. Haitjema, P.H.J. Schellekens (1)   
STC P,  52/1/2003,  P.439
Keywords: interferometry, measurement, non-linearity errors
Abstract : In heterodyne interferometry the accuracy is partly limited by non-linearity errors. These errors are caused by laser polarization state errors and errors of optical components, including alignment. In this paper we present two independent methods to measure the actual polarization state properties of the laser beam. Uncertainties and differences between the methods are discussed. Measurement of a commercially available laser source show ellipticity up to 1:170 in the E-fields and 0,3 ° deviation of orthogonality. This may cause a non-linearity calculated in a heterodyne interferometer of 0,6 nm.
Precision Measurement of Cutting Tools with two Matched Optical 3D-Sensors
A. Weckenmann (2), K. Nalbantic  
STC P,  52/1/2003,  P.443
Keywords: Metrology, Tool, Wear
Abstract : When economically evaluating production systems, it is important to also take the applied tools (cutting inserts, milling cutters, drills etc.) into consideration, as their costs within the life cycle of machine tools are higher than the costs of the actual machines. It is necessary to look holistically at the tool and to measure in detail the geometry of the cutting zone. To ensure this, we propose a new measurement approach with excellent capabilities, based on the combined use of two optical sensors. This approach can be applied to the measurement of tool inserts, which will be the base of further applications on complex cutting tools.
A New Method for Thread Calibration on Coordinate Measuring Machines
S. Carmignato, L. De Chiffre (1)  
STC P,  52/1/2003,  P.447
Keywords: Thread, Calibration, Coordinate Measuring Machine (CMM)
Abstract : This paper presents a new method for the calibration of thread gauges on coordinate measuring machines. The procedure involves scanning of thread profiles using a needle-like probe, achieving traceability by substitution of different thread portions with corresponding paths on a calibrated sphere. The feasibility of applying the method to calibrate a parallel thread gauge with respect to all the relevant thread parameters was demonstrated experimentally using a precision CMM. Application of the comparator approach as described in ISO DTS 15530-3 gave measuring uncertainties comparable to the values from usual calibration methods on dedicated equipment, e.g. a measuring uncertainty of 1.8 µm was achieved for measurement of the pitch, and 2-2.5 µm for diameter measurements.
Locally Controlling Heat Flux for Preventing Micrometre-Order Deformation with Injection Molding of Miniature Products
M. Nakao, M. Yoda, T. Nagao (1)  
STC P,  52/1/2003,  P.451
Keywords: miniaturization, injection molding, heat control
Abstract : This study introduces a method of locally controlling heat flux for preventing micrometre-order deformation with injection molding of miniature products. The experiment used a 98?98?117 mm size mold assembly to produce a box-shaped product of 30?15?6 mm with 1 mm thick walls. The mold had heat flux sensors with thermocouples embedded at depths of 0.3 mm and 0.6 mm from the surface, a sensor to measure the pressure on the ?1 mm ejecting pin, ?1 mm double wall pipe coolers, and ?1 mm bar-shaped heaters. The mold locally controlled the heat flux for each injection cycle or mold zone. The control improved the straightness of the miniature product from 20 ?m to 3 ?m.

 STC S 

Super Bright Light-Emitting Diode for Optical Roughness Characterization
G. Goch (2), S. Patzelt, M. Dressen  
STC S,  52/1/2003,  P.455
Keywords: Roughness, Optical-Measurement, Polychromatic Speckle Pattern
Abstract : A promising in-process roughness measuring technique is based on the detection of polychromatic scat-tered light distributions and speckle correlation algorithms. The spectral light properties mainly influence the measuring range and the resolution. Further approaches use lasers, laser diodes, or a superlumi-nescent diode (SLD), to produce light beams with a discrete or continuous spectrum and a sufficient temporal coherence to generate speckles. The presented approach investigates the suitability of a low-cost super bright light-emitting diode (SLED) for roughness characterization.
Detection of machine lead in ground sealing surfaces
F. Puente Leon, N. Rau   / G. Spur (1)
STC S,  52/1/2003,  P.459
Keywords: Machine lead, Surface texture, Automated visual inspection
Abstract : During the finishing of contact surfaces of rotary shaft lip type seals, unwanted lead patterns may appear. Depending on the direction of rotation, these spiral marks may lead to early leakage or dry run, which may affect directly the longevity of the parts. New methods for satisfying the high requirements of the automotive industry are presented to determine the lead angle, the period length, and the number of starts. In contrast to earlier approaches, with a new fusion strategy, a robust extraction of the parameters of interest is attained even in the case of slightly pronounced lead structures. Moreover, by enhancing the measurement set-up with additional optical components, an in-line inspection becomes possible.
Potentials of Different Process Kinematics in Micro Grinding
B. Denkena, T. Friemuth, M. Reichstein   / H.K. Tönshoff (1)
STC S,  52/1/2003,  P.463
Keywords: Grinding, Surface, Ultrasonic
Abstract : The work described in this paper evaluates the potentials of different process kinematics in micro grinding. First investigations in peripheral and face grinding pointed to specific characteristics of these processes. The machining process can be characterised by the surface quality of the parts. Based on these results improvements for highest surface quality and the reduction of thermal loads are developed. One possibility to minimize the influence of the micro geometry of the grinding tool is the application of ultrasonic grinding. By using an ultra precision machine tool and fine grained grinding wheels high surface qualities can be achieved.
Improvement of Mechanical Strength of Micro Tools by Controlling Surface Characteristics
H. Ohmori (2), K. Katahira, Y. Uehara, Y. Watanabe, W. Lin  
STC S,  52/1/2003,  P.467
Keywords: Micro tool, Surface quality, Mechanical strength
Abstract : Micro tools require exceptionally high surface characteristics, controllable to the nanometer level. In this research, a desk-top machine capable of achieving excellent surface quality and machining accuracy in micro machining was developed, and micro tools of various shapes were prepared using the newly developed machine. The machine successfully prepared pyramidal micro tools with tips of 2µm. The surface of the prepared micro tools was observed closely using some advanced instruments, and the fracture strength of the micro tools was evaluated by indentation tests using a nano-indentation testing instrument. These observations showed a clear and quantitative correlation between the nanometer-level surface quality and mechanical strength. In another test, thin metal sheets were punched using the fabricated micro tool. The resulting holes were found to be of exceptionally high quality.
Frictional Properties of the Micro-Textured Surface of Anisotropically Etched Silicon
N. Moronuki, Y. Furukawa (1)  
STC S,  52/1/2003,  P.471
Keywords: Texture, Friction, Anisotropic etching
Abstract : Anisotropic etching of silicon produces regular shapes that consist of {111} crystal planes. Applying a line-and-space mask pattern, textured surfaces with periodic regular shapes such as V-grooves are easily obtained. This paper first describes the design principle for such textures. By choosing an appropriate crystal orientation, symmetric or asymmetric grooves can be obtained. Variation of the texture profile is also discussed. The frictional properties are then examined. The effects of the texture were: (1) friction could be decreased, and (2) frictional directionality could be obtained with a combination of asymmetric texture and softer materials.
Optical Surface Generation of Organic Nonlinear Crystals by Single-Point Diamond Turning
Y. Namba, M. Saeki   / N. Ikawa (1)
STC S,  52/1/2003,  P.475
Keywords: Optical surface, Diamond turning, Organic nonlinear crystal.
Abstract : Organic nonlinear crystals that are very soft and brittle have been machined into optical surfaces by single-point diamond turning using special machining conditions. The crystallographic orientations of materials to be cut and rake angles of diamond tools strongly affect the cutting mode. The surface roughness depends upon the cutting direction, rake angle and nose radius of the diamond tool, feed rate and lubricant. The surface roughness is not a factor in the depth of cut or cutting speed. The machined surfaces of 23nm p-v in flatness and less than 1nm rms in surface roughness were obtained.
Analysis of Tool and Workpiece Interaction in Diamond Turning
D.A. Dornfeld (1), J.F.G. Oliveira (2), D. Lee, C.M.O. Valente  
STC S,  52/1/2003,  P.479
Keywords: Precision turning, Monitoring, Acoustic emission
Abstract : The surface quality obtained in diamond turning operations is highly influenced by the interaction between the tool and workpiece. These influences include changes in cutting forces, chip formation phenomena, microstructure of workpiece and others. Local changes in the depth of cut and material properties lead to variable cutting forces that may result in unacceptable form errors. This research proposes an innovative approach for mapping the AE RMS generated during diamond turning able to graphically represent several features of the interaction between tool and workpiece related to instant depth of cut distribution, grain boundaries and grain orientation.