A reconfigurable assembly cell for mechanical products
F. Giusti (1), M. Santochi (1), G. Dini (2), A. Arioti  
STC A,  43/1/1994,  P.1
Keywords: Automated Assembling, Flexible Assembly Machine
Abstract : This paper describes the main structural characteristics and the performance of an assembly cell able to accomplish an automated reconfiguration in function of the mechanical product to be assembled. This cell is composed by three baseplates, a pneumatic screwing unit, a hydraulic press and other devices for the complete automation of the assembly operations. The handling functions are performed by a six-axes robot. Particular emphasis has been given to the development of interchangeable fixtures, based on modular elements, which can be easily manipulated by the robot's arm and placed on the workstations of the cell in order to locate, clamp and assembly the product.Finally, some experimental tests concerning the assembly of two products and the capability of a robotized reconfiguration of the system are described.
Knowledge of selecting assembly cell components and its distribution to CAD and an expert system for processing
H. Bley, S. Dietz, N. Roth (2), G. Zintl  
STC A,  43/1/1994,  P.5
Keywords: CAPP, Data Acquisition, CAD
Abstract : During planning an assembly cell, either mechanized or manually driven, knowledge describing the necessities of assembly operations and the capabilities of the future equipment is essential. This domain is analyzed, structured and transformed in order to be processed by an appropriate software system. With this the devices are characterized and selected referring to the specific process demands derived from a product analysis. Geometrical and technological data are to be considered by available software (such as CAD) or specially developed modules. The extension of the CAD system in combination with an expert system improves the efficiency of the planning process as well as the reliability of its result.
Disassembly oriented assessment methodology to support design for recycling
E. Zussman, A. Kriwet, G. Seliger (2)  
STC A,  43/1/1994,  P.9
Keywords: Disassembling, Assessment, Environment
Abstract : This paper describes an assessment methodology to support product design for the "end-of-life" phase. It is based on the assessment of feasible options for disassembling a product and applying recycling processes to its components and subassemblies. The methodology balances the future effort to be invested in recycling processes with the future benefit regainable by reduction of dumping fees and sale of recovered materials, components and subassemblies. It identifies the optimal recycling strategy for a given product with respect to multiple economical and environmental objectives of the designer. The assessment aids the designer by allowing him to compare design alternatives and identify weak spots of the design. The methodology is illustrated by assessing alternative future scenarios for the recycling of a washing machine subassembly.
Analytical and experimental research on assembly systems for molded interconnection devices (3D-MID)
K. Feldmann (2), A. Brand  
STC A,  43/1/1994,  P.15
Keywords: Flexible Assembling, Electronic Production, Process Control
Abstract : The integration of mechanical and electronic functions into three dimensional circuit boards leads to innovative areas of application and possibilities. This obviously is a topical challenge for development of adapted assembly and soldering processes. To solve these problems. analytical and experimental research work is going on with emphasis on mounting SMD's on inclined planes and solderability on thermoplastic devices. Therefore the alternatives of using industrial robots and enlarged SMD-machines are investigated, with the objective to develop new problem orientated Assembly Systems.
A methodology for part feeder design
M.Y. Yeong, W. De Vries (2)  
STC A,  43/1/1994,  P.19
Keywords: Assembly, Design, Parts Feeding
Abstract : A design methodology is presented encompassing the selection, configuration and parametric aspects of parts feeder design. Utilizing analytical. numerical and design tools, the methodology serves as a framework from the initial conceptual stages of design to the design iterations necessary to optimize the design. A case study illustrates this methodology.
Automatic determination of bending sequence in sheet metal products
M. Shpitalni (1), D. Saddan  
STC A,  43/1/1994,  P.23
Keywords: CAPP, Sheetmetal, Bending
Abstract : The bending stage is the most complex and critical stage in manufacturing sheet metal products. Moreover, the automatic determination of the herding sequence is essential within the framework of process planning. Basic examination of the problem immediately reveals that the determination of the bending sequence is a combinatorial problem. Furthermore, it is coupled with the problem of selection of the bending tools. In this paper, the problem of automatic tool selection and bending sequence determination is formulated as a graph search problem. Heuristics, reduction techniques and search methods based on the A-star search algorithm were used to accelerate the solution. The results are superior to previously published results.
Vibration assisted engagement for parts mating
M.C. Leu (2), Z. Katz (1)  
STC A,  43/1/1994,  P.27
Keywords: Mating, Vibration
Abstract : Mating of parts in automated assembly can be assisted by introducing a vibration to one of the mating parts when engagement does not occur. In this paper we will present an analytical and experimental investigation of vibration-assisted parts mating process. In the analysis we will determine the parameters of vibration, including increment of amplitude and number cf cycles, as functions cf the parameters that represent the positional uncertainty and tolerance of the assembly system, for ensuring engagement success. We will also describe the experiments that we perform to validate our analysis and to generate further knowledge contributing to the understanding of this assembly process.
Interconnection of insulated fine wire for PCB
T. Arai (2), T. Kawana  
STC A,  43/1/1994,  P.31
Keywords: Bonding, Wiring, Polymer
Abstract : High density assembly of PCB (Printed Circuit Board) is essential to small-size electronic devices. This paper reports on the interconnection of insulated fine wires of 20-100 micrometer diameters. Three new techniques are discussed: first, the thermal decomposition of high polymer is evaluated quantitatively; second, conditions for solid-state bonding of copper is studied using recrystallization growth rate equation and temperature simulation by FEM; lastly the current control unit for micro resistance bonding is developed. An interconnection machine has been developed, which decomposes high polymer insulation of wires by a CO2 laser and bond them without thermal damage of PCB.


Study on elliptical vibration cutting
E. Shamoto, T. Moriwaki (1)  
STC C,  43/1/1994,  P.35
Keywords: Vibration, Cutting, Chip
Abstract : The paper presents a new cutting method named "Elliptical Vibration Cutting". Synchronized two-directional vibration is applied to the cutting edge in the plane including the cutting direction and the chip flow direction. The chip formed is mainly pulled out by the tool while the tool moves in the chip flow direction, and then the tool is restored to the cutting point without cutting in each cycle of the vibration. Orthogonal cutting experiments of copper are carried out within a scanning electron microscope, and it is observed that the chip thickness and the cutting force are reduced remarkably by applying the method proposed.
Effect of crystallographic orientation on cutting forces and surface quality in diamond cutting of single crystal
Z.J. Yuan (1), W.B. Lee, Y.X. Yao, M. Zhou  
STC C,  43/1/1994,  P.39
Keywords: Crystallographic Orientation, Single Crystal, Cutting Force
Abstract : As the depth of cut in ultraprecision machining is usually less than the average grain size of a polycrystalline aggregate, cutting is performed within a grain. Single crystals are known to be highly anisotropic in their physical and mechanical properties. In this paper, the effect of crystallographic orientation of the substrate material on cutting forces and surface quality in diamond cutting of single crystal copper and aluminium has been studied. Experimental results show that the crystallographic orientation of the workpiece material exerts a large influence on the cutting force and surface roughness. The crystallographic nature of cutting force variation was analyzed based on a microplasticity model. Analytical results compare well with the experimental data. Measures for minimizing the cutting force variation and hence improving the machined surface quality were discussed.
Aspects of surface generation in orthogonal ultraprecision machining
D.A. Lucca, Y.W. Seo, R.L. Rhorer   / R.R. Donaldson (1)
STC C,  43/1/1994,  P.43
Keywords: Cutting, Surfaces, Ultra-Precision Machining
Abstract : The depth of the plastically deformed layer at the workpiece surface which resulted in the orthogonal ultraprecision machining of Cu over the range of uncut chip thicknesses of 0.01-10 µm was investigated. Two tools with the same nominal geometry but with differing edge geometries were used to machine both Te-Cu and fine grain Cu . Tool edge geometries were characterized by atomic force microscopy, taking into account the AFM cantilever tip radius. Magnitudes of the measured depths appear to be consistent with values reported in the literature and those arrived at by simple analyses.
On a possible mechanism of shear deformation in nanoscale cutting
T. Inamura, N. Takezawa, Y. Kumaki, T. Sata (1)  
STC C,  43/1/1994,  P.47
Keywords: Simulation, Micromachining, Cutting
Abstract : Based on the method of transformation from an atomic model to a corresponding continuum model, the stress and strain distributions in nanoscale cutting have been evaluated. The results show that a workpiece is subjected to concentrated compressive and shear train at the primary shear zone, though the area along the rake face of the tool is strained tensilely. The results also show that the interior of the workpiece is, however, exposed to high, almost constant, compressive stress. A possible mechanism of these different stress and strain distributions is discussed as well as its interpretation on a macroscale.
Structure of micromachined surface simulated by molecular dynamics analysis
S. Shimada, N. Ikawa (1), H. Tanaka, J. Uchikoshi  
STC C,  43/1/1994,  P.51
Keywords: Cutting, Micromachining, Simulation
Abstract : Using molecular dynamics computer simulation, a feasibility study is made for the quest of ultimate quality of machined surface attainable in diamond microcutting of copper with a fine cutting edge under hypothetically perfect machine motion. Based on the analyses, the surface generation. process and microstructure of worksurface are well understood from atomistic point of view. In cutting of monocrystalline copper, the worksurface which is free from residual distortion can be obtained and ultimate surface roughness is estimated to be less than 1 nm. In cutting of polycrystalline cooper, nanometrically distorted layer inevitably remains on worksurface. However, the ultimate surface roughness is estimated to be at the same level as that of monocrystalline copper.
Distribution of cutting tool contact loads along rake and flank surface
V. Ostafiev (1), D. Ostafiev, K. Mukhmudov  
STC C,  43/1/1994,  P.55
Keywords: Curve Generation, Contacts, Loads
Abstract : The distribution of contact loads along race and flank surfaces is determined by integration of geometrical and physical parameters of cutting process. The chip formation model has been proposed as trapezium shape lamellar structure formation process. This model has described chip curves, its contact length and contact loads distribution taking into account both plastic and elastic chip deformation. The contact loads distribution on the flank surface has calculated in connection with contact loads value on rake surface. The obtained results are in a good agreement with experiments.
Effects of drill vibrations on cutting forces an torque
D.M. Rincon, A. Galip Ulsoy   / B. Kaftanoglu (1)
STC C,  43/1/1994,  P.59
Keywords: Cutting, Drilling, Vibrations
Abstract : Drill bit vibrations can have an adverse affect on drilling performance resulting in lobed holes, burr formation and tool breakage. An analytical model for predicting torque, thrust and radial forces in drilling has been developed. The model includes the effects of the drill hit transverse deflections which lead to variations from the mean values in the cutting forces. Simulations for a drill, exhibiting increasing elliptical translational motion due to drill vibrations, indicate a significant increase in the ranges of the torque and thrust while maintaining essentially constant mean values. The same qualitative trends are also observed experimentally. The model, when drill vibrations are negligible, reduces to previous models for predicting the mean torque and thrust in drilling. The mean drilling torque and thrust values predicted are in good agreement with experimental data and with previously published models.
Modifications of the cutting edge geometry and chip formation in milling
R. Wertheim (1), A. Satran, A. Ber (1)  
STC C,  43/1/1994,  P.63
Keywords: Milling, Chip Formation, Tool Geometry
Abstract : The research describes the development of milling inserts with new cutting-edge geometries, three-dimensional chipformer configurations, and non-straight and non-continuous cutting edges. The investigation can lead to optimization of the cutting edge and the rake and clearance faces while improving tool life, accuracy, surface quality and chip flow. Results with molded chipformers, helical cutting edges and constant rake and clearance angles are discussed. The geometries include continuous helical and non-continuous, serrated cutting edges for chip splitting and improved force distribution. Higher machining stability, lower forces and improved chip formation can be achieved. With the serrated edge, the chip splits depending on feed and machining direction. Measured chip thickness is larger than the calculated one while chip length is smaller.
Selective transfer built-up layer displacement in high speed machining. Consequencies on tool wear and cutting forces
J.C. Hamann, F. Le Maître (1), D. Guillot  
STC C,  43/1/1994,  P.69
Keywords: Cutting, High Speed Machining, Force
Abstract : The appearance and stability of the selective transfer built up layer (BUL) is studied from a mechanical point of view by its effects on cutting forces in the turning of two austenitic stainless steels with improved machinability. We point out that a displacement of the stable BUL from the face to the flank of the tool as the cutting speed increases enables to keep an acceptable tool life in high speed cutting conditions providing that the tool geometry is appropriate.
Cutting temperatures evaluation in ceramic tools : experimental tests, numerical analysis and S.E.M. observations
S. Lo Casto, E. Lo Valvo, E. Lucchini, S. Maschio, M. Piacentini, V.F. Ruisi   / P. Lonardo (1)
STC C,  43/1/1994,  P.73
Keywords: Cutting Temperatures, Ceramic Tools, SEM
Abstract : The authors propose a multiple approach for the evaluation of cutting temperatures in ceramic tools. The first approach was the experimental evaluation of equitemperature lines, obtained in three-dimensional cutting by employing constant melting point powders scattered on planes parallel to rake face. In the second approach, a numerical finite element analysis was performed. At this step the determination of the percentage of total heat produced in the operation that flows into the tool was considered and, consequently. the temperature distribution within the whole volume of the insert. Finally, the examination of the crater zone with SEM microscopy confirmed the temperature levels as previous estimated.
Characterization of manufacturing processes based upon acoustic emission analysis by neural networks
I. Grabec, E. Kuljanic (1)  
STC C,  43/1/1994,  P.77
Keywords: Manufacturing, Neural Network, Acoustic
Abstract : This article describes the application of a Gaussian neural network for the monitoring of manufacturing processes. The network memory is formed by a self-organized learning process which is stimulated by a multi-component input comprised of acoustic emission (AE) signals and process parameters. By using a trained memory and a non-parametric, multi-dimensional regression the process parameters are associatively estimated from AE signals alone. In this article the on-line estimation of surface roughness during grinding, and the classification of tool sharpness in a drilling process are described. The dynamical forecasting of the AE signal generated in drilling is also demonstrated.
Real time tool breakage monitoring for NC turning and drilling
J.M. Lee (1), D.K. Choi, C.N. Chu  
STC C,  43/1/1994,  P.81
Keywords: Acoustic Emission, Cutting Forces, Fracture
Abstract : This paper presents real-time tool breakage detection by sensor fusion concept of an acoustic emission sensor and a built-in force sensor in turning and drilling processes. Miniature piezoelectric force sensors were inserted in the tool turret housing of an NC lathe and in an auxiliary mounting plate of a machining center. These built-in sensors are economical and do not disturb machining operations. When a tool breaks, a burst type AE signal is followed by a significant drop of cutting force in turning or thrust force in drilling. The AE burst signal was used to trigger cutting force (thrust force) inspection. The algorithm was implemented on a Digital Signal Processing (DSP) board for real-time tool breakage monitoring. Experimental works showed an excellent real-time monitoring capability of the proposed tool breakage detection system.
In-process prediction and prevention of the breakage of small diameter drills based on theoretical analysis
T. Nagao (2), Y. Hatamura, M. Mitsuishi  
STC C,  43/1/1994,  P.85
Keywords: Drilling, Breaking, Predictive Maintenance
Abstract : The in-process prediction and prevention of the breakage of small diameter drills has been investigated. A series of drilling tests has been carried out with newly developed torque-thrust sensors. It has been determined that it is possible to predict and prevent drill breakage by monitoring the torque and the thrust, since these force components rise suddenly and exceed threshold values just before the breakage. To determine the appropriate threshold values, the stress due to the torque, the stability of drill motion and the temperature rise at the drill tip have been analyzed theoretically. From these calculations, the maximum shear stress in the drill, the combinations of angular velocity and thrust values which lead to instability and an expression for the temperature rise at the drill tip have been obtained.
Wear characteristics of cermet cutting tools
H.K. Tönshoff (1), H.G. Wobker, C. Cassel  
STC C,  43/1/1994,  P.89
Keywords: Cermet, Wear
Abstract : Turning tests were carried out with different cermet grades and workpiece materials. Real production processes with permanently changing mechanical and thermal loads were simulated by cut-in/cut-off cycles. The wear behaviour of cermets used in cyclic cutting is not governed by the same laws as in continuous cutting. This is due to the effect that in cyclic cutting the tool life depends both on the wear rate and the occurence of cracks and microchipping. The cracks are caused by the alternating thermal load. This was proved by corresponding simulations with a laser device. As the occurence of microchipping is more or less accidental, the reliability of the wear behaviour decreases with increasing frequency of load cycles. Furthermore, the influence of cermet compound, tool geometry, workpiece material and coolant on the wear behaviour was investigated. Worn cutting tips as well as annealed cermet/steel-sandwiches were analysed with regard to the chemical interaction between tool material and workpiece material.
Turn-milling of hardened steel - An alternative to turning
H. Schulz (1), T. Kneisel  
STC C,  43/1/1994,  P.93
Keywords: Turn-Milling, Hard Cutting, CBN
Abstract : Turn-milling with parallel axes is a relatively new method for precision machining of rotationally symmetrical workpieces. Here the kinematic conditions and their influence on the design of tools and the choice of technological parameters are shown. Using CBN while cutting hardened steel (> 62 HRC) a tool life is achievable which clearly exceeds that of the hard-turning process. Surface qualities beneath R_Z < 2 ?m can be achieved.
Relation between process energy and tool wear when turning hardfacing alloys
K. Weinert   / L. Cronjäger (1)
STC C,  43/1/1994,  P.97
Keywords: Turning, Plasma, Wear
Abstract : When turning weld deposited cobalt-based alloys with PCBN-tools, there exists an optimum of cutting speed concerning the tool wear. The amount of this cutting speed depends on the cutting conditions. In the succession of continuous cut, machining with unsteady depth of cut, and intermittent cut, the cutting speed optimum increases from 90 m/min up to 330 m/Min. Using a plasma arc to heat up the workpiece in front of the tool, the minimum of tool wear can be shifted to lower cutting speeds. Together with the minima of flank wear, minima of the total cutting force occur. Compared to conventional machining, the total cutting force can be reduced.
Chip Flow and notch wear mechanisms during the machining of high austenitic stainless steels
H. Chandrasekaran (2), J.O. Johansson  
STC C,  43/1/1994,  P.101
Keywords: Turning, Wear, Stainless Steel
Abstract : Notch wear at the depth of cut line is a serious problem during the machining of high-austenitic stainless steels. The mechanism of such notch wear was investigated through special step-turning tests involving four high austenitic stainless steels with cemented carbide tool. Chip studies and micro-hardness measurement of work material at the chip flow region, alone with SEM studies were carried out to elucidate the role of work hardening and chip flow upon wear. These clearly showed severe localised shear and chip side flow and its strong adhesive interaction with the tool material in the notch region. The critical initiation of the notch seems to he related to factors such as, transverse stress and temperature distribution and chemical interaction. Subsequent progress of notch was often through the interaction of the localised shear region of the chap and the exposed binder phase o£ the tool. Direct evidence between the strain hardening index of the work materials and the level of notch wear was also observed.

 STC Dn 

Application of the theory of inventive problem solving to design and manufacturing systems
V.R. Fey, E.I. Rivin (1), I.M. Vertkin  
STC Dn,  43/1/1994,  P.107
Keywords: Design Algorithm, System Development
Abstract : The paper presents basics of a little known in the West algorithmic system for solving engineering problems developed by G. S. Altshuller and his school in the former USSR. The algorithmic system provides a powerful tool for solving conceptual design problems. It is based on the formulated Laws of Evolution of Engineering Systems and consists of three subsystems: the Algorithm for Inventive Problem Solving, the Standard Solutions to Inventive Problems, and the Database of Physical, Chemical, and Geometrical Effects. Several examples of application of this system for obtaining non-obvious solutions to real life engineering problems are described.
Basic layout design with multiple-layered decision making and transit evaluation
H. Shinno, Y. Ito (2), H. Tadano  
STC Dn,  43/1/1994,  P.111
Keywords: Design, Decision Making, Machine Tool
Abstract : In the design procedure, mature designers always analyze and synthesize various requirements and conduct necessary information processing so as to have the moss suitable result. In order to rationally automatize such a synthetic procedure, it is necessary to effectively transplant the information processing function of the designer into a computer system. Thus, in this paper, a novel decision making methodology has been proposed to establish a future intelligent CAD system for the basic layout. The proposed methodology is based on the multiple-layered decision making with the transit evaluation function, and its validity has also been verified through case studies on the design of a main spindle system in machine tools.
An interactive refinement methodology for early stage exploration of design space during system design
S.Y. Reddy, S.C.Y. Lu (2)  
STC Dn,  43/1/1994,  P.115
Keywords: System Design, Computer-Aided Design, Concurrent Engineering
Abstract : The design of large engineering systems requires the quick exploration of design space. Though simulation models have been used to support optimal design of individual subsystems, similar approaches cannot be used for system design, because of the difficulties in using the disparate simulation models for different subsystems and perspectives together, in addition to the ensuing excessive computational requirements. This paper presents a methodology for system design, called Hierarchical and Interactive Decision Refinement (HIDER), which combines machine learning based adaptive modeling, multiple-objective optimization, and interactive refinement techniques to provide decision support for quickly exploring the design space. The paper also presents results from the application of HIDER to the system design of a wheel loader. In this example, complex simulation models for cycle time analysis and stability analysis are used for the design of the wheel loader simultaneously from these two perspectives.
An integrated modeling environment using the metamodel
H. Yoshikawa (1), T. Tomiyama, T. Kiriyama, Y. Umeda  
STC Dn,  43/1/1994,  P.121
Keywords: Computer Aided Design, Modelling, Knowledge Based System
Abstract : One of the central issues of intelligent CAD is building a modelling mechanism that deals with multiple models. The basis on which a model is built, which we call ontology, may vary over domains of modelling, abstraction and approximation levels, and granularities. This paper discusses integration of design object models over multiple ontologies. The key idea is the use of meta level model about relationships among models. The meta-level model, which we call the metamodel, is used for reasoning about how models should he generated and modified so that consistency among them can be maintained. The use of the metamodel is illustrated by an example of modelling a hydrofoil.
Conceptual graphs in CAD
O.W. Salomons, F. Van Slooten, G.W.F. De Koning, F.J.A.M. Van Houten (2), H.J.J. Kals (1)  
STC Dn,  43/1/1994,  P.125
Keywords: CAD, CAPP, Features
Abstract : This paper elaborates on the use of conceptual graphs in a prototype of a computer based support system for re-design. Re-design support involves the modelling of assemblies and components. The requirements of the components to be modelled are a compromise between the functioning of the assembly and the manufacturability of the individual components. Conceptual graphs provide for an elegant way of representing both functioning and manufacturing aspects. In the prototype system, conceptual graphs are used for representing and defining assemblies, components and features as well as the relations between these entities. Constraints, such as kinematic, tolerance and manufacturing constraints are also represented using conceptual graphs.
Application of constraint propagation in part family modelling
M. Mäntylä, K. Lagus, T. Laakko   / G. Sohlenius (1)
STC Dn,  43/1/1994,  P.129
Keywords: Computer Aided Design (CAD), Knowledge Based Systems, Constraints
Abstract : The paper describes the use of an incremental constraint propagation technique for feature-based modelling of group technological part families. The constraint representation is based on a multigraph where nodes represent constrained variables and multiarcs the various constraints. Through the variables, the multigraph is integrated with a LISP frame based feature representation. A constraint specification language for representing constraint types in feature and part family definitions is also discussed. The system has been implemented in the context of the EXTDesign feature based modelling system developed at the Helsinki University of Technology. The work is considered a contribution to computer-aided design methodology.
3-D interacting manufacturing feature recognition
S.R.T. Kumara (2), C.Y. Kao, M.G. Gallagher, R. Kasturi  
STC Dn,  43/1/1994,  P.133
Keywords: Manufacturing Feature Recognition, CAD/CAM, Neural Network
Abstract : Automatic recognition of machining features such as slots, holes and pockets is one of the major tasks of CAD/CAM. This research proposes the super relation graph (SRG) method for extracting shape features. The nodes of the SRG represent the faces in depressions, the links represent either super-concavity or face-to-face relationships which are generated from a set of new definitions of relationships between two faces. Hypotheses are generated from a combination of graph-based and neural network approaches. These hypotheses are verified using computational geometry techniques. The SRG method is implemented in an object oriented paradigm and the results obtained are proved to be better than the ones generated from most of the prominent existing methods.
Application of fuzzy set theory to set-up planning
S.K. Ong, A.Y.C. Nee (1)  
STC Dn,  43/1/1994,  P.137
Keywords: Computer Automated Process Planning, Jigs and Fixtures, Fuzzy Set Theory
Abstract : Computer-aided process planning and computer-aided fixture planning have been widely researched in the last two decades. Most of these computer-aided systems are, however, either dealing only with process planning or fixture design. This paper advocates set-up planning as a link between these two functions. A set-up planning system for the machining of prismatic parts on a 3axis vertical machining centre is proposed. This system formulates set-up plans based on the initial, intermediate and final states of a part. The system uses the fuzzy set representation, along with production rules and object representation. This hybrid representation scheme aptly depicts the inexact relationships among features required on a final part, and with those currently present on the part. These inexact relationships, which greatly affect set-up planning, are manifestations of the various process and fixture planning constraints in the system. The consideration of these features' relationships together with the intermediate states of a part, allow the system to plan forward without the need to backtrack. Through this representation, the set-up planning problem is formulated using the fuzzy set theory. Using this approach, the proposed system is able to generate set-ups that fulfil the process and fixture planning requirements that are commonly practised by experienced planners.
Configuration and dimensional synthesis in mechanical design : an application for planar mechanisms
P. Makkonen, J.G. Persson (2)  
STC Dn,  43/1/1994,  P.145
Keywords: Design, Synthesis, Mechanism Optimisation
Abstract : An approach to synthesis of mechanical systems in the conceptual and dimensional phase is done by combining topological and dimensional design with graph theory. The topological synthesis is done in two parts. First, part and joint number synthesis is done from the Grübler equation. The synthesis is continued by a grammatical approach. The theory of generative grammar has been applied to mechanisms, and by using this approach, a "grammar of mechanisms" has been formulated. The level of grammar is specified and grammatical rules have been derived from the constraint equations. An example of topological synthesis of mechanisms utilising the developed grammar is presented. Finally, the dimensional synthesis of the mechanism topologies is done utilising non-linear programming (the gradient method) with addition of a penalty-function to avoid discontinuities.
Distribute product design
F.L. Krause (2), T. Kiesewetter, S. Kramer  
STC Dn,  43/1/1994,  P.149
Keywords: Concurrent Engineering, Product Design, Project Management
Abstract : Distribution of design tasks is a measure to accelerate the product design process. In a distributed design environment based on broadband communication network it is feasable to split the design task into functional and shape related subtasks. Under the supervision of a project management system the design tasks can be worked out in parallel and independently. The product model of the design system can include information about design space, design constraints and connections to other design subtasks.
The utilization of hypermedia based information systems for developing recyclable products and for disassembly planning
D. Spath   / H. Weule (1)
STC Dn,  43/1/1994,  P.153
Keywords: Product Design, Disassembling, Information Systems
Abstract : When products are considered in the context of their overall life-cycle, there is an increased requirement fo; information on the various life-phases involved. Information on disposal options determines the product design concept, and conversely the product design parameters affect the degree of rationalization achievable in disassembly. The resultant need to provide ecologically relevant product data both for development engineers and for disassembly planners in the context of the specific requirements concerned entails the necessity of using computer-aided information systems. This paper presents an information concept of this kind for supporting development engineers in implementing recyclable product designs, plus a procedure for planning and supporting manual disassembly. In methodological terms, systematized approaches are employed for design evaluation and procedures for qualification-oriented disassembly planning. Initial software developments are indicated for practical applications based on Hypermedia.
Challenges in product strategy, product planning and technology development for product life cycle design
V.A. Tipnis (2)  
STC Dn,  43/1/1994,  P.157
Keywords: Product Strategy and Planning, Environmental Impact, Technology Development
Abstract : The growing emphasis on design for sustainability requires that the harmful side effects to workers, users, and local and global natural ecosystems must be minimized by reducing the rate of material and energy consumptions that lead to the harmful side effects. As corporations face stricter regulations on emissions, effluents, and solid waste disposal, they are forced to develop technologies for disassembly, re-manufacturing, and recycling as well as for higher energy efficiency products and processes. The challenge of design for sustainability has, therefore, forced corporate product strategists and product development planners to address the following series of questions: How to formulate a competitive product strategy for environmentally-safe product life cycle design? What should be the product life cycle? How long? Should the product be 'sold' or 'leased'? How to set correct competitive targets for product function, features, performance. quality and reliability? How should the product realization process be organized to ensure designed-in' quality into products without missing the product introduction target timing or target cost? Environmentally-safe product life cycle design requires the product design and manufacturing expertise at the stage of the product strategy formulation itself. A methodology for the formulation of competitive product strategy is presented as a starting point for design for sustainability.
Linear and geometric accuracies from layer manufacturing
T.H.C. Childs (2), N.P. Juster  
STC Dn,  43/1/1994,  P.163
Keywords: Concurrent Engineering, Inspection, Manufacturing Processes
Abstract : A benchmark component has been designed to test the geometrical capabilities of the photo-polymerisation, selective laser sintering, laminated object manufacturing and fused deposition modelling layer manufacturing rapid prototyping processes. It assesses not only linear accuracies but geometric tolerances, repeatability, resolution limits and the ability to create manufacturing features such as fillets and draft angles. Repeatability measurements on the benchmark show that the layer manufacturing technologies rank differently in the small scale (less than 5mm), the medium scale (20 to 25mm) and the large scale (up to 250mm). The superiority of the photo-polymerisation processes in the small scale is lost at medium and large scales. Measurement ranges are mainly from 0.05 to 0.5mm.


Linear shaped YAG laser beam with uniform power density distribution applied to machining of ceramics
T. Miyazaki, Y. Tanaka, T. Tokunaga   / N. Kinoshita (1)
STC E,  43/1/1994,  P.167
Keywords: Laser Beam Machining, Ceramics
Abstract : A single mode YAG laser beam is transformed into a linear beam of uniform power density distribution, which is shaped through a shaping mask, a convex lens and a cylindrical lens. The mask eliminates the surrounding part of the beam with low power density and generates the uniform density distribution. The convex lens converges the beam and generates a high power density beam. The cylindrical lens transforms the circular beam into the linear shaped beam. A ditch with sharp edge can be obtained by scanning the shaped beam; the ditch depth can he controlled by varying the focusing position of the beam. This optical system is applied to produce profiles of saw blade and notch in ceramics with numerical control systems for the workpiece.
Laser material interaction : absorption coefficient in welding and surface treatment
G. Ricciardi (2), M. Cantello  
STC E,  43/1/1994,  P.171
Keywords: Laser, Welding, Surface Treatment
Abstract : Efficient energy coupling between beam and material is fundamental for any effective application of laser technology. Qualitative & quantitative experimental assessments on laser radiation absorption phenomena during moth high power density (welding) and low power density operations (surface treatments) are providing useful information on process energy balance in order to achieve a deeper understanding of the absorption mechanism, and to collect a wide amount of data, a starting point for any consistent modelling of results.
Ultrasonic-aided laser drilling of aluminium-based metal matrix composites
W.S. Lau (1), T.M. Yue, M. Wang  
STC E,  43/1/1994,  P.177
Keywords: Ultrasonic, Laser Beam Machining, Composite
Abstract : In pulsed Nd:YAG laser drilling of aluminum-based metal matrix composites (MMCs), it is well known that there are problems of limited maximum depth-of-drill, non-cylindrical hole profile and the presence of excessive re-cast material which are associated with the conventional process. A novel combined ultrasonic-laser machining technique has been developed to improve the overall quality of laser drilled holes. It has been proven that this ultrasonic-aided laser machining technique not only increase the depth-of-drill, but also improves the quality of the hole. A mathematical model is proposed to describe the shape of the machined hole.
Magnetic abrasive finishing of rollers
M. Fox, K. Agrawal, T. Shinmura, R. Komanduri (1)  
STC E,  43/1/1994,  P.181
Keywords: Superfinishing, Roller, Polishing
Abstract : Advanced ceramics, such as silicon nitride are increasingly being considered for structural applications, such as ceramic bearings for high speed spindles. The requirements of high finish and accuracy and minimal surface defects, such as cracks, combined with the difficulty of finishing them by conventional methods of grinding and polishing cost effectively, necessitated the investigation of alternate manufacturing technologies. Magnetic field assisted polishing is one such technology which is capable of generating (a) very high finish and accuracy, (b) very little or no surface damage, such as microcracks to the components during the finishing operation due to extremely low level of forces, and (c) the finishing operation can be significantly faster than by conventional techniques due to the possibility of using higher spindle speeds. In this paper, this technique will be briefly reviewed followed by an experimental investigation of the application of this technology for finishing of stainless steel (non-magnetic) rollers to simulate non-magnetic silicon nitride. Surface finish (Ra) of the order of 10 nm can be obtained. Some of the parameters of the process that effect the finish and material removal rate are discussed.
Magnetic fluid grinding - A new technique for finishing advanced ceramics
N. Umehara   / S. Kalpakjian (1)
STC E,  43/1/1994,  P.185
Keywords: Polishing, Ceramics, Ferromagnetic Materials
Abstract : Most advanced ceramics are finished by conventional grinding followed by polishing. However, due to the brittle nature of these materials. the grinding process introduces surface defects, such as cracks which can significantly reduce the strength and reliability of the parts in service. Also expensive diamond abrasives and long polishing times add significantly to the cost of manufacture. To address these concerns, a new polishing technique, known as magnetic fluid grinding, was developed that uses controlled low level force during polishing. The process is found to produce more accurate surfaces at significantly less time than conventional polishing. The paper presents the principles of this technique, design of magnetic fluid grinding cell, salient features of the process, and results of finishing balls, rollers, and plates using his technique.
A combined electrical machining process for micronozzle fabrication
T. Masuzawa (2), C.L. Kuo, M. Fujino  
STC E,  43/1/1994,  P.189
Keywords: Electrical Machining, Micro-Machining, Hole
Abstract : Smaller diameters are required for various types of precision nozzles. However, the accuracy of nozzle holes is a problem in mechanical machining processes and the choice of inner shapes is limited. A combined process with EDM, ECM and electroforming is proposed for the production of nozzles with small diameters and various inner shapes. Nozzle holes with the diameters of 6-100 micrometers were successfully produced with good concentricity to the outer profile. Some technical characteristics of the process were also investigated.
High precision wire-EDM by on-line wire positioning control
D.F. Dauw (2), I. Beltrami  
STC E,  43/1/1994,  P.193
Keywords: Wire EDM, Accuracy, Precision
Abstract : The paper deals with a technical realization to improve the Wire EDM accuracy. The system which is readily available on commercial wire EDM machines is based on the on-line tracking and control of the wire position. The deviation of the wire position relative to the programmed wire path position is continuously measured and corrections are being made during the machine cutting. This technique allows to cut complex shapes, arc paths and contours at a much faster cutting speed as compared to conventional wire EDM machines. Practical examples are discussed and the economical relevance is emphasized.
WEDM identification and adaptive control for variable height components
K.P. Rajurkar, W.M. Wang, J.A. Mc Geough (1)  
STC E,  43/1/1994,  P.199
Keywords: Physical and Chemical Machining, Wire EDM, Adaptive Control
Abstract : Wire rupture in wire EDM is caused by high temperature due to high power density determined by discharge frequency and workpiece height. This paper reports a new WEDM adaptive control system that monitors and controls the spark frequency according to the on-line identified workpiece height. The workpiece height is estimated by using a non-linear discrete model relating cutting speed with spark frequency. This system controls the spark frequency at optimal levels to avoid wire rupture and to maintain the maximum productivity. The error of the workpiece height identification is 1 mm and the response to changes in workpiece height is 1 second.
On-the-machine measurement in EDM process by a calibration system with polyhedra
N. Mohri, H. Takezawa, N. Saito   / K. Osakada (1)
STC E,  43/1/1994,  P.203
Keywords: Electrical Discharge Machining, Measuring Instruments, Calibration
Abstract : In order to realize electrical discharge machining (EDM) with high precision, it. is necessary to take into account of the change of the shape of electrode and workpiece with machining time. This paper deals with on-the-machine measurement of an electrode and a workpiece in electrical discharge machining (EDM). A newly developed calibration system with polyhedra is installed on the machine. The probe can he detached from the machine in machining stage and it is attached to the machine in measuring stage at any attitude according to the portion being measured. The position of the edge of a measuring probe is determined with the equations of planes on the polyhedron. This paper describes the principle of calibration method and the change of complex shape of in electrode and a workpiece measured in the process of machining.


Prediction of ductile fractures in metal forming processes : an approach based on the damage mechanics
N. Alberti (1), A. Barcellona, L. Cannizzaro (2), F. Micari (2)  
STC F,  43/1/1994,  P.207
Keywords: Failure, Forging, Damage
Abstract : The Authors propose a new approach for the prediction of ductile fractures in bulk metal forming processes: the approach is based on a numerical analysis able to take into account damage occurrence and evolution in constitutive equations. The model supplies the distribution of the void volume fraction in the workpiece during the deformation path: consequently, the comparison to a critical value, determined by means of a simple tension test, allows to predict the growth of defects. The proposed approach has been applied to the drawing process: the numerical results have been compared with a set of experimental tests showing a good predictive capability of the model.
Formability of rapid solidification processed hypereutectic Al-Si alloys
F.A.C.M. Habraken, J.H. Dautzenberg (2)  
STC F,  43/1/1994,  P.211
Keywords: Forming, Ductility, Aluminium
Abstract : Rapid Solidification Processing (RSP) offers significant advantages when applied to hypereutectic aluminium-silicon alloys: If compared to cast Al-Si alloys, higher strength levels, lower thermal expansion and increased wear resistance can be obtained. The materials studied are Al19Si5Fe, Al18Si5Fe2Ni, Al17Si3.5Cu2Ni and Al22Si3.5Cu2.5Ni (wt. %37;) made by the 'Melt Spun Ribbons'-process and Al25Si5Fe2Ni produced by spray-deposition. At this moment, these materials are applied in e.g. pistons for high performance engines. For economical use in mass-production, these materials have to be formed into their (semi-) final shape. This formability is subject of the paper. It gives an overview of this property for a variety of forming conditions, ranging from extrusion to sheet metal forming. The formability of the materials is quantified. A comparison with conventional materials is made and various formed parts are shown.
Extended capabilities in metal forming processes by a new interdisciplinary FEM-code
M. Herrmann   / M. Geiger (1)
STC F,  43/1/1994,  P.215
Keywords: Forming, Process Modelling, Finite Element Method
Abstract : The design and implementation of a new software system within a joint interdisciplinary project was initiated to offer new, extended capabilities in the field of nonlinear finite element analyses. Flexibility, portability and expandability are important qualities of the new software system. Modern relational database software was introduced as an interface to the environment and as a material data base. A technique of handling thermomechanically coupled problems with independent FEM meshes is presented. A new method to model history-dependent interface behaviour based upon the surface representation by segments has been implemented.
Application of the slab-finite element method for improvement of rolled bar surface quality
K. Sawamiphakdi, G.D. Lahoti (2)  
STC F,  43/1/1994,  P.219
Keywords: Bar, Finite Element Method, Rolling
Abstract : This paper presents a methodology to improve bar surface quality by using the slab-finite element method. The improper design of roll geometries and roll pass sequences may lead to underfilled or overfilled conditions in the finished bars. The analysis was conducted using the special purpose slab-finite element program TASKS with some modifications. The parametric analysis was performed by using several roll geometries. The potential roll geometry to produce an excellent bar surface quality was selected for an in-plant trial and excellent bar surface quality was consistently obtained.
Optimization of a cooling system : The cooling of pilgered seamless tubes
W.E. Carscallen, J. Jeswiet (2), P.H. Oosthuizen  
STC F,  43/1/1994,  P.223
Keywords: Cooling, Rolling, Pilgering
Abstract : This paper describes the design of a cooling system for Pilger Rolling. The design changed a turbulent flow regime (a mist) to a laminar one with an improved method of delivery. Also, the new design led to production improvements and increased capabilities in the company; for instance: increased production rates [10-20%37;], with an increase in quality; extended tool life [mandrel and rollers], hence less downtime and increased productivity; increased consistency in the product, hence less quality problems and rework; significant improvements in the production environment - cleaner air in the factory.
Investigation into nonsteady-state three-dimensional extrusion of a trocoïdal helical gear by the rigid-plastic finite element method
D.Y. Yang   / K. Lange (1)
STC F,  43/1/1994,  P.229
Keywords: Forming, Extrusion, Finite Element Method
Abstract : In metal forming, there are problems with recurrent geometric characteristics and without explicitly prescribed boundary conditions. In such problems, so-called recurrent boundary conditions must be introduced. The present study deals with non-steady-state three-dimensional finite element analysis for extrusion of a trocoidal helical gear through a curved die. The boundary-directed remeshing scheme based on the modular remeshing technique is developed to reduce the errors arising in fitting old and new mesh systems. The computed extrusion pressure in reaching the near steady-state loading stage is compared with the results of the experiment and the steady-state analysis. The three-dimensional deformed pattern involving warping at the extruded end due to torsional deformation mode is demonstrated.
Finite element analysis of three-dimensional metal flow in cold and hot forming processes
W.T. Wu, G.J. Li, J.P. Tang   / T. Altan (1)
STC F,  43/1/1994,  P.235
Keywords: FEM Simulation, Cold and Hot Forming
Abstract : Two-dimensional FEM (Finite Element Method) codes capable of solving axisymmetric and plane strain industrial forming problems, are widely and routinely used in the metal forming industry. In most practical cases, however, to solve 3D problems, the engineers must handle them in a 2D manner, which is only an approximation. To deal with 3D real world problems more accurately, a 3D-FEM code was recently developed. In this paper, the current capabilities and features of this 3D code are briefly described with examples and by comparing, whenever possible, the numerical predictions with experimental measurements. Future work will include the development of a 3D automatic mesh generator, a more efficient computational method, and a more user friendly post-processor.
FE-simulation of the precision forging process of bevel gears
E. Doege (1), H. Nägele  
STC F,  43/1/1994,  P.241
Keywords: Forging, Bevel Gear, Finite-Element Method
Abstract : Up to date high precision parts like bevel gears are manufactured by warm or hot forging with a subsequent cold calibration for the determination of the exact geometry. At the IFUM a precision forging technology has been developed for the manufacturing of bevel gears whereby the cold calibration operation of the workpieces can be eliminated, which leads to considerable costsavings. With the aid of the Finite-Element Method forging processes can be simulated realistically, thus reducing the number of necessary experiments. This paper presents the results of the FE-analysis of the manufacturing process and the comparison with experimental results.
A new method to design blockers
S.I. Oh (2), S.M. Yoon  
STC F,  43/1/1994,  P.245
Keywords: Metal Forming, Die Design, Digital Filter
Abstract : This paper investigates a new method to design blocker geometry in rib-web type closed die forging. By examining various forging and blocker geometries, it was found that blocker geometry can be generated by eliminating high frequency mode from finisher geometry. In order to formalize the procedure, low pass filters, which can convert finisher to blocker geometry, are proposed. Also discrete Fourier transform is used for computational efficiency. The blocker geometry designed by the present method are compared with the one by an experienced designer. The blocker geometries are also validated by using FEM simulation. Present results shows that the frequency approach may offer a promising method to design blocker automatically.
The residual stress distribution in the wall of a deep drawn and ironed cup determined experimentally and by FEM
J. Danckert (2)  
STC F,  43/1/1994,  P.249
Keywords: Deep Drawing, Residual Stress, FEM
Abstract : A two stage axisymmetric deep drawing process followed by ironing of the cup wall has been simulated with the explicit FEM code LS-Dyna2D. The results show that thee ironing process causes a drastic change in the residual stress distribution; the residual stresses are lowered and a much more favourable distribution with regard to fatigue and stress corrosion is obtained. The FEM results cornpare favourably with experimental results.
Forming limits in hydromechanical deep drawing
N. Bay (2), S.S. Jensen, M.P. Malberg, S. Grauslund  
STC F,  43/1/1994,  P.253
Keywords: Hydromechanical Deep Drawing, Forming Limits
Abstract : A systematic approach predicting the possibility of forming complex shapes in hydromechanical deep has been developed The method is based on knowledge about the limiting curve of drawing-in of the flange caused by fracture, adopting different initial drawing ratios, when drawing circular, cylindrical cups. This limiting curve is called the master curve. Using geometrical considerations the curve representing drawing-in of the flange in hydromechanical deep drawing of a complex shape is constructed and compared with the master curve. Successful predictions of the possibility of forming or fracture in drawing stepped and control cups in stainless steel were obtained.
Development of a computer-controlled drawbead simulator for sheet metal forming
K.J. Weinmann (2), J.R. Michler, V.D. Rao, A.R. Kashani  
STC F,  43/1/1994,  P.257
Keywords: Sheet Metal Forming, Tooling, Computer Control
Abstract : A multiple-action hydraulic sheet metal strip drawing test device has been constructed for the purpose of studying the effectiveness of feedback controls in sheet metal forming. The apparatus simulates the flow of sheet metal in the blankholder and over the die shoulder during the stamping of sheet metal panels. Its special features consist of the ability to adjust both blankholder force and drawbead penetration while the strip is being drawn. A force transducer was developed to measure the forces in the sheet on either side of the die shoulder. Measurements from this unique transducer determine both the drawbead restraining force in the simulator and friction between the sheet and the die shoulder. Data demonstrating the capabilities of the equipment are presented.
Improving workpiece quality in swivel bending with new tools and a 2-D tool path
E. Von Finckenstein (1), L. Kessler, M. Kleiner, G. Reil, R. Schilling, R. Warstat  
STC F,  43/1/1994,  P.263
Keywords: Bending, Tools, Simulation
Abstract : Swivel bending has become a widely used industrial forming process for larger bent part. By a new tool construction the movement of the tool relative to the sheet can be minimized, which leads to a better surface of the sheet and a better surface of the bending line. A 2-D controlled tool path of the Swivel clamp, whore the control data come from a process simulation, can improve the quality of the workpiece as well. Both improvements of the forming process are shown with experimental and simulation results.
Compensation of tilting and horizontal displacement of upper die, relative to the lower die at out of center forming load by a closed loop control system
K. Siegert   / D. Schmoeckel (1)
STC F,  43/1/1994,  P.267
Keywords: Forming Press, Hydraulic Equipment, Control System
Abstract : This paper presents a new method of compensation, including a closed loop control system for the tilting and horizontal displacement of the ram. At the Institute for Metal Forming at the University of Stuttgart, a floating clamping plate, attached to the ram by hydraulic cylinders, was developed. This clamping plate can be horizontally and vertically positioned by a closed loop control system using proportional valves. By experimental research, done with a hydraulic 4000 kN single acting press, it was shown that compensation of the tilting and horizontal displacement of the upper die relative to the lower die is possible.
A new method to detect solid fractions of mushy/semi-solid metals and alloys
M. Kiuchi (1), S. Sugiyama  
STC F,  43/1/1994,  P.271
Keywords: Forming, Metal, Semi-Solid
Abstract : A new method to detect so-called solid fractions of mushy or semi-solid metals and alloys is proposed. Firstly, the relationships between electric resistance ( or electric potential difference ) and temperature in the range from solid-line to liquid-line are measured with respect to binary alloys and multi-component alloys. Secondly, the relationships between solid fractions of mush or semi-solid binary alloys and their temperatures are obtained by referring their equilibrium phase diagrams. By combining both results, the unified relationship between normalized electric potential difference and solid fraction is obtained for all of the tested binary alloys. This relationship is used to determine the solid fractions of multi-component alloys from their measured normalized electric potential differences. The assumed values are verified by the rapid solidification method.
Deterministic injection molding for quality plastic parts manufacturing
K. Yamazaki (2), K. Shoda, M. Fujikawa  
STC F,  43/1/1994,  P.275
Keywords: Injection Molding Machine, Quality Control, High Precision Injection
Abstract : The paper deals with a study on the injection molding system for manufacturing high quality plastic products. The problems of the conventional in-line screw injection machine were analytically and experimentally studied. To solve problems, a new injection machine with the mechatronics control system was designed and developed. The developed system features a sim_p lified pre-plasticating type mechanism with new control system using full-software closed loop servo control with neuro-fuzzy control. The developed system demonstrated an excellent stability by which a product can be manufactured with very consistent quality and accuracy for long time without human operator intervention.


Heat affected zones in grinding steel
M.C. Shaw (1), A. Vynas  
STC G,  43/1/1994,  P.279
Keywords: Grinding, Surface Damage, Thermal Damage
Abstract : Two well known forms of metallurgical damage of ground surfaces involve untempered and overtempered martensite. Both of these forms of metallurgical damage involve martensitic transformations. This paper reviews the nature of such transformations and the special characteristics that pertain in grinding where the time at temperature before quenching is unusually short.
Analytical and experimental investigation of burn-out in creep-feed grinding
C. Guo, S. Malkin (1)  
STC G,  43/1/1994,  P.283
Keywords: Grinding, Thermal, Creep
Abstract : Creep-feed grinding operations require a copious fluid flow for cooling at the grinding zone. Cooling effectiveness in creep-feed grinding depends upon a critical burn-out limit beyond which fluid film boiling occurs, cooling becomes ineffective, and the temperature rises catastrophically. In the present paper, a thermal analysis is presented to predict the burn-out heat flux limit at a critical temperature for Film boiling. The thermal model considers the transient workpiece and fluid temperatures during a grinding pass and the energy partition to the workpiece. Measurements of the burn-out heat flux are found to be in good agreement with theoretical predictions over a wide range of creep-feed grinding conditions.
A general thermal model for grinding with slotted or segmented wheel
H.W. Zheng (1), H. Gao  
STC G,  43/1/1994,  P.287
Keywords: Grinding, Thermal Model, Temperature
Abstract : Grinding with shined or segmented wheel as one of affective ways to reduce grinding thermal damage, has keen utilized in many fiend. In this paper two thermal models for periphery grinding with slotted wheel and vertical spindle face grinding with segmented wheel are established respectively in order to choose the slotting or segmental parameters more reasonable and predict grinding temperature. Further more a general thermal modal is developed which not only unifies the above theoretical models but also contains the J-C..Jaeger's and Des.Ruisseaux's thermal models. Experimental results are also given to verify the models developed in this paper.
Dimensional characterization of grinding wheel surface through acoustic emission
J.F. Gomes De Oliveira, D.A. Dornfeld (2), B. Winter  
STC G,  43/1/1994,  P.291
Keywords: Grinding, Grinding Wheel Measurement, Acoustic Emission
Abstract : An approach is proposed for measuring the grinding wheel geometric characteristics by using the dressing tool as a touch probe and the acoustic emission level generated in the contact as a trigger for the dimensional measurement. The interaction between the dressing tool and the grinding wheel is experimentally studied. Three interaction levels are observed: turbulence, elastic and brittle. In the elastic contact the grinding wheel surface is not damaged by the dressing tool. This condition is investigated based in the topographic characteristics of the interacting surfaces. The analysis shows that it is possible to measure grinding wheel characteristics using this system.
An approach to monitoring of the grinding process using acoustic emission (AE) technique
W. Hundt, D. Leuenberger, F.H. Rehsteiner, p. Gygax (1)  
STC G,  43/1/1994,  P.295
Keywords: Monitoring, Acoustic Emission, Grinding
Abstract : For optimization and control of the grinding process it is necessary to monitor the process state and the wear state of the grinding wheel. In a European project for this purpose AE was measured during the process and analyzed in a frequency range up to 3.5 MHz. Single grain experiments showed different wear phenomena to be readily distinguishable by their individual AE signature at these frequencies. The high grain contact frequency of a real process. however, produces strongly overlapping AE signals. A strategy was developed to separate and describe several different AE sources. Their correlation to physical events is the object of further research.
Acoustic emission for process control and monitoring of surface integrity during grinding
J.A. Webster, I.D.Marinescu, R.T. Bennet   / R. Lindsay (1)
STC G,  43/1/1994,  P.299
Keywords: Acoustic Emission, Grinding, Surface Integrity
Abstract : This study suggests that acoustic emission sensing may be a useful tool for controlling the grinding process, and the following observations can be made: fluid coupling to the grinding zone is easy to implement and is effective; AE is superior to force for detecting wheel/work contact at start of cycle:: using RMS signal processing may result in the loss of important surface cracking and contact data; most AE sensors distort the signal from the process but deconvolution can restore the signal; normal force/AE ratio shows a good correlation with cross-lay surface roughness.
Material removal mechanisms in grinding ceramics
B. Zhang, T. Howes (2)  
STC G,  43/1/1994,  P.305
Keywords: Grinding, Ceramics, Mechanism
Abstract : This paper discusses material-removal mechanisms in grinding of ceramics using single-point diamonds and diamond wheels. The ground lavers were analyzed using_ SEM, FLM and other inspection methods. Material pulverization was discovered on the surface layer of ground ceramics. A powder regime was observed which appeared to result from pulverization, which was the dominant material-removal mechanism as long as depth of cut was smaller than a critical value. Material flowed sideways in single-point grinding, forming pile-ups on both sides of a groove. The size of the powder regime and the coefficient of pile-up were measured in various grinding conditions.
Effect of grit depth of cut on strength of ground ceramics
J.E. Mayer Jr., G.P. Fang   / R.L. Kegg (1)
STC G,  43/1/1994,  P.309
Keywords: Grinding, Ceramics, Strength
Abstract : Experimental research has been conducted into the effect of grit depth of cut on the flexural strength of ground hot pressed silicon nitride. Wheel grit size and machine parameters of wheel depth of cut and workspeed in surface grinding have been investigated. The results indicate that the primary factors which control the strength of ground ceramics are grind direction and the grit depth of cut. The findings point the way to grinding conditions to achieve maximum strength grinding of ceramics and to maximum specific material removal rates at these conditions. Additionally, the most appropriate method for computing the wheel grit depth of cut was identified.
On performance of brazed single-layer CBN wheel
A.K. Chattopadhyay (2), H.E. Hintermann (1)  
STC G,  43/1/1994,  P.313
Keywords: Grinding, CBN, Loading
Abstract : In brazed single layer CBN wheel, high grit exposure but with strong grit-bond adhesion is known to be the most distinguished feature The present investigation has, however, revealed that in spite of having a large grit protrusion, the consistency of performance of such a wheel may be affected by the manner how the density as well as the uniformity of grit distribution are regulated in the monolayer configuration. This is particularly true when a chip accommodation problem leading to wheel loading exists. Experiments with monolayer CBN wheel varying in grit density and under various grinding conditions have further revealed that pre-brazing placement and fixation of CBN grit on the tool substrate with an even distribution and adequate inter-grit spacing may remarkably enhance the flexibility of application of a high protrusion single-layer CBN wheel.
Development of highly homogeneous pellets applying electrophoretic deposition of ultrafine abrasives for nanometer grinding
J. Ikeno, Y. Tani, H. Sato (1)  
STC G,  43/1/1994,  P.319
Keywords: Grinding Wheel, Abrasives, Mirror
Abstract : This paper is concerned with how to fabricate highly homogeneous pellets for nanometer in grinding. The realization of a. minute grain depth of cut is an important feature for obtaining a smooth surface by grinding. Hence i is profitable to apply a grinding wheel composed of ultrafine abrasives of diameters of 10 to 20s. T ^-, .P, grinding wheel with suitable bonding strength brings about grain-sized self-sharpening in a grinding process. Hence it can prevent the occurrence of swarf loading and grain dulling which weaken the grinding ability. As a result, the highly homogeneous grinding ti feel earl yield a smooth surface of less than 10nm,p-v for both hard and brittle materials. Ultrafine abrasives which are negatively charged can be deposited uniformly on an anode 'Dy applying electrophoretic deposition. Hence a homogeneous ultrafine grinding wheel can be fabricated by applying this technique.
Generation of parabolic and toroidal surfaces on silicon and silicon based compounds using diamond cup grinding wheels
Z. Zhong, V.C. Venkatesh (1)  
STC G,  43/1/1994,  P.323
Keywords: Diamond Grinding, Aspheric Optical Surfaces, Silicon
Abstract : This paper presents the methods and experimental results using diamond cup wheels and CNC machining centers for grinding parabolic and toroidal surfaces made of Si and SiC, the former for use as a thermal imaging lens and the latter for synchrotron radiation facilities. Generation of aspheric surfaces, by zonal material removal, on Si using cup grinding wheels and a 5-axis machining center was investigated. Theoretical and experimental investigation of the grinding and material parameters that influence ductile grinding are discussed. Ductile grinding is possible with wheels having small grit size and with proper combination of feed and unit normal load; a resinoid bonded wheel promotes this more easily than a metal bonded wheel, though at the expense of profile accuracy. Profile analysis, surface integrity, and examination of grinding swarf using digital imaging are discussed. Also, generation of toroidal surfaces on SiC using metal-bonded cup wheels, a 3-axis machining center and a micro-displacement table with piezoelectric actuators was studied. Toroidal SiC mirrors were ground with good shape accuracy, mirror finish, and low surface roughness. The time consumed in the process is very short. The machines used are inexpensive and not specially designed for ultra-precision grinding.
Molecular dynamics simulation for abrasive processes
R. Rentsch, I. Inasaki (1)  
STC G,  43/1/1994,  P.327
Keywords: Micro-Machining, Abrasion, Simulation
Abstract : Until today several applications of Molecular Dynamics in mechanical engineering fields have been carried-out, focusing on the simulation of indentation tests or cutting processes. In this paper the application of Molecular Dynamics for Abrasive Processes is discussed and the first results from simulations are presented which are targeting on the pileup phenomenon in abrasive machining. Particularly the differences and necessities in contrast to the simulation of cutting processes are taken into account. Some principal problems and components of the model representation as well as applied techniques in indentation and cutting simulations are discussed in more detail. Finally new methods to improve the model representation and to enhance the calculation speed for large models are given.


Comparison of limit surface approach with other approaches in fixture planning with friction
S.H. Lee, K.K. Cho (2)  
STC M,  43/1/1994,  P.331
Keywords: Fixture Planning, Limit Surface, Force Torque Space
Abstract : A fixture planning module is being developed as part of a computational system for concurrent product and process design. In general, three kinds of constraints such as geometric, kinematic, force constraints are considered to provide an appropriate fixturing for a given machining process. Since many fixture arrangements rely on friction to hold a part, the ability to reason about faction is an important component of fixture planning. Limit surface in force/moment space are introduced as a convenient formalism to check whether parts will slip and to help in specifying clamping forces. In this paper, the use of limit surfaces obtained either by scanning over the space of possible motions or by Minkowski sums is compared with other four approaches to establishing the relationships among applied forces and moments and the corresponding direction of sliding motion. Since the other approaches in the literature have only been applied to planar examples, the discussion in this paper will he confined to the case of a planar pressure distribution.
Vibrations and surface generation in slab milling
U. Heisel   / J. Milberg (1)
STC M,  43/1/1994,  P.337
Keywords: Machine Tools, Dynamic, Surface Generation
Abstract : In slab milling the quality of the machined surface is directly influenced by the dynamic behaviour of the machine tool. In addition to the cycloidical microgrooves, the dynamic relative motion between the workpiece and tool is superimposed on the machined surface. In general these vibrations cannot be directly identified by investigating the machined surface. By the application of a special purpose milling cutter, microgrooves are generated which are identifiable and from which the relative motions in the cutting zone can be determined by surface topography measurement. It is shown how the groove structure is produced as a function of the kinematics of the process and the relative motions in the zone of cutting. An example based on experimental investigation is used to illustrate the procedure used to determine these relative motions based on analysis of the workpiece surface.
New concept of machining by means of 6-axis control
Y. Takeuchi (2), M. Sato, H. Suzuki  
STC M,  43/1/1994,  P.341
Keywords: Machining Center, Control, Grooving
Abstract : The study deals with a new machining concept by making use of 6-axis control. 6-axis control implies that a cutting tool allows three rotational movements for positioning as well as three translational ones. A 6-axis control machining center equipped with a main spindle capable of tool orientation in addition to conventional 5-axis control structure is developed. A non-rotational cutting tool is mounted at the main spindle to carry out the 6-axis control machining, which allows a variety of machining possibilities. In the study, a control software for grooving with an asymmetric cross section is presented together with experimental cutting results.
New interface machine/tool : hollow shank
M. Weck (1), I. Schubert  
STC M,  43/1/1994,  P.345
Keywords: Interfaces, Tools, High Speed Machining
Abstract : The 7124-taper shank no longer complies to the demands of today's manufacturing technology. Therefore, together with tool and machine tool manufacturers and end users, the WZL at the RWTH Aachen developed a new interface between machine tool and tool, the hollow shank. This paper describes the possibilities and applicational limitations of the new interface, which became a DIN-Standard in 1993, with regard to the maximal permissible rotational speed, the possible bending and torsion moments and the stiffness and accuracy.
A hierarchical open architecture CNC system for machine tools
Y. Altintas (2), W.K. Munasinghe  
STC M,  43/1/1994,  P.349
Keywords: CNC Design, Adaptive Control, Tool, Monitoring
Abstract : This paper presents a hierarchical open architecture multi-processor CNC design for machine tools. The system's primary bus accommodates the computer modules which look after the user interface, machining process control and monitoring tasks. The secondary bus of a high performance CNC module is used for communication with dedicated micro-controller based drive control modules. There is an open flow of position, feed and machining commands and states between CNC master, machining process control and monitoring modules in the system. Sample test results for parallel implementation of NC tool path control, adaptive cutting force control and tool breakage detection are shown to illustrate the openness of the designed system for intelligent machining operations.
To accurately control the speed of motion along parameterized space curves. Principle and application of a new algorithm in CAM/CNC and robotics
G. Yu   / G.N. Levy (1)
STC M,  43/1/1994,  P.355
Keywords: Machines, CAM/CNC, Speed Control
Abstract : To accurately control the speed of motion along parameterized space curves is a common requirement in CAM/CNC, robotics and computer animation. Because of the usually non-linear relationship between the parameterizing variable and the arc length, it is very difficult to find an accurate specification for a given speed profile along a parameterized curve. The current solutions are unsatisfactory. In this paper we describe the principle of a new algorithm and the algorithm itself, without a brief mathematical derivation of the algorithm, by which the relative deviation of the approximated speed from the desired speed for any given speed profile along any parameterized space curve is ensured to be smaller than a given tolerance. In addition, the use of the algorithm in practice is simple and no extensive calculation is required.
Design and control of robot with flexibilities
W.H. Elmaraghy, H.A. ElMaraghy (1), A. Zaki, A. Massoud  
STC M,  43/1/1994,  P.359
Keywords: Robots, Control, Design, Flexibility
Abstract : Industrial and special robots are used increasingly in applications requiring fast motions and high accuracy, while manipulating large payloads. Joints and links flexibility limit the performance of such robots by introducing resonant frequencies in the range of the control bandwidth. Two robots were designed and built to better understand the dynamics and demonstrate the control of such robots under challenging operating conditions. One of the robots is a 3D anthropomorphic robot with two flexible links, and the other is a two link planar robot with changeable, built-in joint flexibility. Robust and adaptive control algorithms have been demonstrated. The experimental results illustrate the difference between various control algorithms in meeting the required goals.
New predictive solutions to very high speed machining
D. Dumur (2), P. Boucher (2)  
STC M,  43/1/1994,  P.363
Keywords: Machine Tools, CNC, Control System
Abstract : Improving performances of machine-tools can be achieved with predictive control laws instead of classical P.I.D. controllers. Previous studies dealing with Generalized Predictive Control (G.P C.) have proved that a better efficiency is possible. coupled to a simple implementation due to autotuning procedures. However, the limitations of these techniques may be reached with strong specifications of very high speed machining. This paper presents new gradual solutions to the cascade control of C.N.C, machines with very severe objectives. First a multirate predictive algorithm, attractive to benefit of the different dynamics of the loops, can be considered as a positive answer to an increase of rapidity, thus a decrease of the sampling period, only of possible use if a cascade structure is required. The second solution develops, in case of very Small sampling periods, a version of G.P.C. using the delta operator instead of the time shift operator, to avoid oversampling and sensitivity to the accuracy of the transfer function coefficients. The possibilities of these two versions are analysed on an experimental benchmark and compares to results obtained with "classical" G.P.C. algorithms.
Accurate motion controller design based on an extended pole placement method and a disturbance observer
H. Van Brussel (1), C.H. Chen, J. Swevers  
STC M,  43/1/1994,  P.367
Keywords: Automation, Continuous Path Control, Algorithms
Abstract : The paper describes an innovative integrated design method for accurate tracking in motion control applications, in the presence of external disturbances like friction, cutting forces, etc. First, an extended pole placement method is developed to design feedforward controllers for applications with known future input commands, like in feeddrives for machine tools. It results in a noncausal reference model with a low-pass characteristic with selectable bandwidth and zero phase shift. A new feedback design approach, based on a state and disturbance observer is introduced. A loop transfer recovery procedure tunes the observer gains to compromise optimally between performance and robustness.
Stochastic modeling and on-line adaptive control of cutting forces in turning
L. Harder, M. Nicolescu   / B. Lindström
STC M,  43/1/1994,  P.373
Keywords: Cutting Forces, Real-Time Identification, Adaptive Control
Abstract : This paper presents the development of a new parameter-adaptive control system for on-line cutting force control in turning. The control system adjusts the feedrate in-process in order to compensate for the varying machinability of the cutting process. Since the machining system -consisting of the cutting process and the machine tool structure - is a system with time-variable dynamics, it is necessary for the control system also to identify the process parameters and adapt the regulator correspondingly in real-time in order to avoid instability problems. The system presented in this paper is based upon stochastic modeling, recursive identification and pole-assignment design. The paper includes a theoretical analysis, and the applicability of the system is demonstrated by experimental test results.


Random manufacturing system : a new concept of manufacturing systems for production to order
K. Iwata (1), M. Onosato, M. Koike  
STC O,  43/1/1994,  P.379
Keywords: Optimization, Flexible Manufacturing System, Decision Making
Abstract : Manufacturing systems are now required to have a capability to cope with the changes of manufacturing conditions and to carry out efficient production continuously. The concept of Random Manufacturing System (RMS) is proposed in order to realize flexible and adaptive production for dynamically-changing orders. RMS consists of machine agents each of which can decides its own schedule. The operation of RMS is carried out according to the tender-based decision making. In this paper; the basic concept, architecture, and operation procedure of RMS are introduced, and methods for improving RMS performance and two simulation systems are explained.
Workflow modelling for advanced manufacturing concepts
H. Rozenfeld, A.F. Rentes   / W. König (1)
STC O,  43/1/1994,  P.385
Keywords: Integration Methodology, Modelling, Work Flow
Abstract : This paper proposes a metamodel based on CIM-OSA principles representing the enterprise operation. It leads to workflows constructs through a meta data base derivation. lt is proposed also a methodology for manufacturing integration. It supports a business process reengineering allowing workflow modelling. In this context a software tool for enterprise modelling was developed. So it is possible to get a better understanding of business process. supplying subsidies for [SO 9000. for supporting system benchmarking and other applications.
Decentral production scheduling of assembly systems with genetic algorithm
H.P. Wiendahl (1), R. Garlichs  
STC O,  43/1/1994,  P.389
Keywords: Production Scheduling, Monitoring, Genetic Algorithm
Abstract : In todays companies the shifting of functions from central divisions to the production areas leads to new requirements in the field of production planning. Flexible planning systems using algorithms which are adapted to the needs and the objectives of the different production areas are necessary to fulfill these new demands. Therefore a graphical-oriented decision support system for the decentral production scheduling of assembly systems is presented. The scheduling algorithm of this system is a genetic algorithm.
Cellular manufacturing in highly specialised supply industries
R. Rössle, R. Züst   / B. Schumacher (1)
STC O,  43/1/1994,  P.397
Keywords: Cellular Manufacturing, Group Technology, Order Processing
Abstract : Cellular Manufacturing describes the realisation of new product oriented organisational structures. Traditional Methods of Group Technology are often unsuitable to receive such structures if parts have to be manufactured based upon customers orders and design. These methods are based upon static aspects. "Make-to-Order" suppliers are highly determined by dynamical aspects. The variety of products is continuously changing, the behaviour of such manufacturing systems is effected by a large diversity of customer orders and customers demands. This paper presents an approach to Cellular manufacturing based on dynamical aspects. A model using external effects is proposed. These are the System of Objectives, the Variety of Orders and the Variety of Products.
Engineering a dialogue between Science and Society
J. Peters (1)  
STC O,  43/1/1994,  P.401
Keywords: Human, Engineering, Society
Abstract : Engineering and technology stay as a permanent "closed loop" between Science and Society. This regenerative process can become unstable when unbalances take place between the different elements. In particular present economic situation calls for a far-going disconnection between human labor and machine work, provided the goods produced by the machines are honestly redistributed within the global human society. The notion of profit also must be reconsidered in all its dimensions as well as the manufacturing system as such which has been subjected to a profound change due to the impact of the information technology upon the closed system mentioned above.
Zero-defect manufacturing by means of a learning supervision of process chains
E. Westkämper   / H.J. Warnecke (1)
STC O,  43/1/1994,  P.405
Keywords: Optimization, Quality Assurance, Modelling
Abstract : Highly productive and low-stock or "just-in-time" manufacturing systems require safe manufacturing also in the process chain. Starting from a systematic analysis of defects and their causes in single-product and series production, a method has been developed enabling the supervision of quality in the process chain as well as its optimization by means of a learning management system. For this, quality data collected are evaluated and represented in mathematical process models. From these data, logic patterns are derived by means of cluster analyses or statistical analyses, which provide information on the causes and the assessment of nonconformities. Based on this and with the help of high-performance parallel computing, it has become possible to realize zero-defect manufacturing in process chains by means of a knowledge and neuronal-network-based learning system.
A systematic method for renewal of production technology
A. Bilberg, L. Alting (1)  
STC O,  43/1/1994,  P.409
Keywords: Optimization, Logistic, Productivity
Abstract : Productivity is important for all manufacturing companies, but even so many fail to utilize their resources due to poor management. organization, planning, layout etc. A study carried out at 10 Danish companies reveals that a large improvement potential exists. The paper will discuss the results of this studio and will present a systematic method for productivity improvement. In all companies more than 10%37; productivity improvement has been obtained through more effective layouts, logistics policies, better organization, application of information technology etc. The conclusion in most cases is that a minor non-expensive change can have a major effect on the overall performance of the companies. The method combines traditional business tools with the newest research tools, such as simulation and monitoring aiming at setting diagnosis, generating plan of actions and demonstrating the consequences before the improvements are implemented.
Efficient automated geometric feature recognition through feature coding
P.K. Venuvinod, C.F. Yuen   / E. Merchant (1)
STC O,  43/1/1994,  P.413
Keywords: Feature Recognition, Feature Coding, Process Planning
Abstract : Automated geometric feature recognition (GFR) is a commonly encountered task in the creation of any process planning or design for manufacturing software, This paper describes a new method based on feature coding for automated GFR. An enhanced winged edge data structure including surface type labels and a Multi-Attributed Adjacency Matrix (MAAM) is generated from the CAD model of the given object. The MAAM fully captures the topology and coarse geometry of the object for the purposes of GFR. A simple algorithmic method extracts each feature from the object-MAAM. the feature-MAAM is then processed to generate 'a unique code which is recognised and interpreted by matching it with entries in a Feature Database. The method is significantly superior to previous GFR methods in terms of computational efficiency and the reduced need to invoke expert rules. Unlike previous methods. the system car handle objects with plane, cylindrical as well as other analytically definable curved faces and can recognise both simple and complex features i.e. those formed by interactions amongst simple features.
Computer aided process planning techniques for complicated aircraft structural parts
J.K. Li (2), Z.H. Huang, H. Shen  
STC O,  43/1/1994,  P.417
Keywords: Optimization, Computer Automated Process Planning (CAPP), Expert System
Abstract : Since the complexity of the aircraft structural parts, which are key parts to be machined in aircraft production, they can not be involved by any existing CAPP system. This paper deals with the techniques used for the development of a CAPP system for aircraft frames, ribs and beams. Integrate with a CAD system, this CAPP system inputs part information from the CAD outputs and transforms them into feature data by the aid of part coding. A 6- orientation, hierarchical and frame structure is used for the description of part features and their connections. Process planning decisions are made by an expert system according to structural and technological features of parts. Process documents are automatically generated including a part sketch in each operation.
Tolerancing and sheet bending in small batch part manufacturing
L.J. De Vin, A.H. Streêm, H.J.J. Kals (1)  
STC O,  43/1/1994,  P.421
Keywords: Tolerancing, Sheetmetal, CAPP
Abstract : Tolerances indicate geometrical limits between which a component is expected to perform its function adequately. They are used for instance for set-up selection in process planning and for inspection. Tolerances must be accounted for in sequencing and positioning procedures for bending of sheet metal parts. In bending, the shape of a part changes not only locally, but globally as well. Therefore, sheet metal part manufacturing presents some specific problems as regards reasoning about tolerances. The paper focuses on the interpretation and conversion of tolerances as part of a sequencing procedure for bending to be used in an integrated CAPP system.
A new approach of group technology part families optimization
K.K. Hon (2), H. Chi  
STC O,  43/1/1994,  P.425
Keywords: Manufacturing Systems, Group Technology, Genetic Algorithms
Abstract : The key question of forming a group technology (GT) based manufacturing system has attracted numerous attempts in applying various optimization techniques. This paper presents a new approach of optimizing GT part family formation by genetic algorithm (GA) which is based on the principles of natural selection. A genetic algorithm model combining a coding design, a penalty factor and a scaling operation wan developed for this purpose. Results generated from four case examples, and comparisons with three other heuristic methods demonstrated that the genetic algorithm approach provides a powerful and effective numerical tool for the optimization of GT part-families.
Information modelling for technology oriented tool selection
W. Eversheim (1), M. Lenhart, B. Katzy  
STC O,  43/1/1994,  P.429
Keywords: Feature, Cutting Tool, Information Modelling
Abstract : Based on the feature approach a new method for selection and configuration of tools is developed for turning, drilling and milling operations. This method takes into account mainly technology factors besides the workpiece geometry and the process strategy. Selection rules are developed and transformed into real tool parameters according to the new standardization aspects on tool characteristics. The planning functions are integrated into an object oriented engineering database. In this context the required resource models and the STEP (Standard for the exchange of Product Model Data) based information models are explained. The potentials of the implementation are discussed in regard to rationalization targets.
Optimal tool selection based on genetic algorithm in a geometric cutting simulation
Y. Mizugaki, M. Hao, M. Sakamoto   / H. Makino (1)
STC O,  43/1/1994,  P.433
Keywords: Optimization, CAM, Tooling
Abstract : This paper presents new methods of offset surface generation and milling tool selection. Firstly the calculation of a workpiece's area cut by a tool is done by detecting contact points between the tool and the workpiece in a lattice space model. Secondly the tool selection is made by Genetic Algorithm to minimize the total machining time and the uncut area. A tool set is coded as a binary hit string. It is assumed the tools would be used in the descent order of radius and cut their corresponding area as entirely as possible. Simulations and conclusions are briefly described.
Computer-aided constrained optimization analyses and strategies for multipass helical tooth milling operations
E.J.A. Armarego (1), A.J.R. Smith, J. Wang  
STC O,  43/1/1994,  P.437
Keywords: Milling Optimization Strategies, Multipass Milling Optimization, Machining Optimization Software
Abstract : The development of computer-aided constrained optimization analyses and strategies for multipass peripheral and end-milling operations are outlined and discussed. The constrained optimization is based on criteria typified by the maximum production rate and includes a range of practical constraints of relevance to rough milling such as the machine tool limiting power, torque, feed force and feed-speed boundaries. It is shown that a combination of mathematical optimization analyses and limited use of numerical search techniques provides clearly defined computer-aided strategies which guarantee the final global optimum solutions. Simulation studies have verified the software and demonstrated the superiority of multipass over single pass.
Optimisation and dynamic adaptation of the cutter inclination during five axis milling of sculptured surface
J.P. Kruth (1), P. Klewais  
STC O,  43/1/1994,  P.443
Keywords: Milling, Tool Path, Sculptured Surfaces
Abstract : Five axis milling allows to machine free form surfaces with cylindrical or toric cutters instead of ball nose cutter. This drastically reduces the machining time. Commercial CAM modules however require the NC-programmer to specify the appropriate inclination of the tool with respect to the work piece surface normal. This is difficult especially for complex parts with varying surface curvature. This paper presents five axis CAM software which varies the tool inclination during the tool path generation, in order to achieve the best combination of scallop height, workpiece accuracy, surface roughness and machining cost. Machining time to produce some free form workpieces, given a maximum scallop height, could be reduced by 50%37;.
Optimization of the process parameters of injection molding with neural network application in a process simulation environment
G.H. Choi, K.D. Lee, N. Chang, S.G. Kim (2)  
STC O,  43/1/1994,  P.449
Keywords: Injection Molding, Neural Networks, Simulation
Abstract : The process parameters of injection molding have been set by human operators based on their experience iteratively. Even with the sophisticated CAE software tools, at present time, the interpretation of the analysis results and the subsequent process parameter adjustment are being done based on the human expertise. A learning system has been developed to generate an optimum set of process parameters at the design stage with a minimum number of CAE simulation runs.


Angle interferometer cross axis errors
J. Bryan (1), D.L. Carter, S.L. Thompson  
STC P,  43/1/1994,  P.453
Keywords: Metrology, Angular Measurements, Calibration
Abstract : Summary: Angle interferometers are commonly used to measure surface plate flatness. An error can exist when the centerline of the double comer cube mirror assembly is not square to the surface plate and the guide bar for the mirror sled is curved. Typical errors can be one to two microns per meter. A similar error can exist in the calibration of rotary tables when the centerline of the double comer cube mirror assembly is not square to the axes of rotation of the angle calibrator and the calibrator axis is not parallel to the rotary table axis. Commercial double corner cube assemblies typically have non-parallelism errors of ten milli-radians between their centerlines and their sides and similar values for non-squareness between their centerlines and end surfaces. The authors have developed a simple method for measuring s these errors and correcting them by remachining the reference surfaces.
Improving the accuracy of angle measurement system with optical grating
G.X. Zhang (1), C.H. Wang, Z. Li  
STC P,  43/1/1994,  P.457
Keywords: Precision Engineering, Angular Measurements, Optical Gratings
Abstract : A new angle measurement system with optical grating is presented in the paper. Its distinguishing features are: (1) Gratings having sine function transmissivity are used as the index gratings. The harmonic errors of the Moire fringes are greatly reduced. (2) Errors caused by zero offsets, inequality in amplitude and nonorthogonality in phase of two Moire fringe signals are corrected by real time software error correction. (3) Four unequally spaced reading heads are used to eliminate the errors caused by the graduation error of optical grating and error motions of the spindle. The experimental device gives an accuracy about 0.2 arcseconds.
Development of an optical hole-diameter measuring instrument
H. Onikura, Y. Kuwabara, T. Nakamura, T. Sajima, Y. Imaseki, A. Katsuki   / A. Kobayashi (1)
STC P,  43/1/1994,  P.461
Keywords: Optical Measuring Instrument, Hole, Accuracy
Abstract : An optical hole-diameter measuring instrument has been developed. The instrument, which consists of two laser diodes, a photo sensitive detector, two condenser lenses and some mirrors, is intended to measure, based on trigonometry, the distances to the hole wall on two sides alternately. The fundamental analysis and experiment showed that it was possible to measure the distances to the object having not only a mirror-like plane surface but also a rough cylindrical surface, Using the instrument, which was manufactured on trial, it was found that the hole-diameter between 9.5 and 11.0 mm could be measured within accuracy of 23 ?m.
Task specific gauge for the inspection of coordinate measuring machines
T. Pfeifer   / G. Spur (1)
STC P,  43/1/1994,  P.465
Keywords: Bevel Gear, Calibration, CMM-Uncertainty
Abstract : Coordinate measuring machines (CMMs) frequently are used for measuring tasks at bevel gears even though probing at inclined tooth profiles causes enormous length measuring uncertainties. In order to analyse these faults on principle a master bevel -ear can be used, which however is very difficult to manufacture and to calibrate in a sufficient accuracy. Therefore a task specific gauge consisting of basic geometric elements has been developed, which can he calibrated with smallest uncertainties. After the tested CMM has probed a grid of defined measuring points, the maximum quality of bevel gears to be measured can he assessed.
Design of a fast, short stroke hydraulic actuator
H.D. Tran, D.B. De Bra (1)  
STC P,  43/1/1994,  P.469
Keywords: Ultra-Precision, Hydraulic Actuator, Non-Circular Cutting
Abstract : We developed a fast, short stroke hydraulic actuator, suitable for toolpost actuation, for spindle motion error correction or for non-circular cutting. The actuator has a throw of 180 ?m at 2 MPa. The dynamic response is limited by the hydraulic resonance (? 20,000 rad/s). The choice of servovalve and feedback design govern the dynamic response. It shows rise times of better than 25 ms, with accuracies suitable for ultraprecision machining. In a facing operation, a surface finish of better than 25 nm R_a was achieved, and for noncircular cutting, about 40 nm R_a .


Advantages and industrial applications of three-dimensional surface roughness analysis
L. De Chiffre (2), S. Christiansen, S. Skade  
STC S,  43/1/1994,  P.473
Keywords: Surface Roughness, Digital Analysis, Industrial Applications
Abstract : Based on more than a decade's work with digital surface roughness analysis techniques, this paper describes the advantages as well as the range of application of three-dimensional surface roughness analysis. Conventional as well as optical equipment is used for surface mapping, and a number of specially developed software packages perform the data processing, including three-dimensional surface filtering and computation of three-dimensional parameters to describe selected functional aspects of surface topography. Several cases of industrial applications are referred, ranging from seal leakage to die wear and human skin diseases.
Grinding mode identification by means of surface characterization
H. Trumpold (1), M. Hattori, C. Sutsumi, C. Melzer  
STC S,  43/1/1994,  P.479
Keywords: Surface, Ceramic, Ductile Transition
Abstract : A new method was developed to characterize ground ceramic surfaces. The method is based on the evaluation of planar areas caused by ductile mode conditions. The necessary three-dimensional topography data of the surfaces were obtained by SEM. Applying the evaluation method, surfaces ground by the two opposite grinding modes, ductile grinding and brittle fracture grinding, can be distinguished. Moreover, the percentage of ductile regime ground surface in mixed mode surfaces can be determined. The method was verified using ceramic samples of different material, machined applying different mesh numbers of grinding wheel and increase of depth of cut respectively.
A generalized model of the surface generation process in metal cutting
K.F. Ehmann (2), M.S. Hong  
STC S,  43/1/1994,  P.483
Keywords: Surface, Generating, Machining
Abstract : Machined surfaces are generated by a variety of processes. each of which produces a surface with its own characteristic topography. A method for the prediction of the topography of the generated surfaces has been developed based on general models of the machine tool's kinematics and a generalized model of deterministic and non-deterministic cutting tool geometries. The model termed the surface-shaping system accounts for not only the nominal or global motions of the machine but also takes into account errors during machining such as tool runout, machine deformation and vibration, as well as higher order motions. Based on the surface shaping system model a computer simulation system has been developed which facilitates the 3D graphical representation and evaluation of the topography of the generated surface.
Contractless surface measurement with a new acoustic sensor
G. Goch, R. Volk   / H. Kunzmann (1)
STC S,  43/1/1994,  P.487
Keywords: Surface, Acoustic Sensor, Contact-Free
Abstract : A standard diamond tip fixed to a micromechanical tuning fork (,32 kHz) is guided by piezo-electric actuators in a controlled distance of about 100 nm along the inspected surface. The small acoustic fork oscillation (constantly excited) is (mainly) damped by the air gap between diamond tip and surface. Thus, constant output signal of the high-C oscillatory circuit indicates that the tip traces the surface roughness in a constant distance. First results carried out at roughness standards, map the profiles obtained mechanically. Difficult materials like laquers, glasses, ceramics were investigated.
The minimum coefficient of friction : what is it ?
N.P. Suh (1), M. Mosleh  
STC S,  43/1/1994,  P.491
Keywords: Friction, Surface Engineering, Tribology
Abstract : For many decades, researchers have widely believed that the frictional force is mainly due to adhesion, an assertion that has not been supported by experimental results. On the contrary, it has been shown that much of the frictional force between dry sliding surfaces in a typical engineering application is due to mechanical interactions. In this paper, a means of reducing the contribution of mechanical effects on friction through surface engineering is presented. Friction coefficient as low as 0.05 between dry sliding surfaces has been achieved when the mechanical interactions are eliminated. This result has been achieved based on a hypothetical model of an ideal surface for low friction. Model experiments were done using a hard smooth surface coated with a sub-micron thick elastomer layer. Such low friction in engineering systems without lubricants can have a major impact on the design of many precision machine components.
Measurement of surface roughnesses and topography at nanometer levels by diffuse X-ray scattering
D.K. Bowen, M. Wormington   / P.A. McKeown (1)
STC S,  43/1/1994,  P.497
Keywords: Nanotechnology, Surface, Roughness
Abstract : Instrumentation for diffuse X-ray scattering has recently been improved to the point at which measurements may be made in a laboratory instrument in times that are competitive with stylus instruments for areal scans on high-quality surfaces. Theoretical models have also been implemented with efficient algorithms that permit rapid extraction of surface roughness, spatial bandwidth and correlation length from the data. The method is non-contacting, does not depend on detailed knowledge of optical constants, and gives information on roughnesses between 0.05 and 5 nm, on correlation lengths from sub-nanometre to tens of micrometres and on fractal dimensions between 2 and 2.95. The Xray method is compared to atomic-force microscopy, and is shown to give similar results for a specimen measurable by each technique, but also to have greater speed and vastly reduced data acquisition requirements when averaged data are sought. The X-ray methods have a lower cut-off length and are both non-contacting and non-destructive. An application to high-quality Zerodur surfaces is shown.