THE INTERNATIONAL ACADEMY FOR PRODUCTION ENGINEERING

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CIRP ANNALS 1995

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 STC A 

Assembly planning software
S. Grewal, p. Tran, A. Bhaskare   / L. Farmer (1)
STC A,  44/1/1995,  P.1
Keywords: Assembling, Planning, Computer Aided Planning (CAP)
Abstract : A research programme at the CAIRO has led to the development of a professional software package for assembly system design and management. This product is now being trialed in various manufacturing organisations The research activity focused on part attributes for assembly, the generic assembly tasks involved, the issue of precedence in assembly, the equipment requirements, the assembly times, and the line balancing for single and mixed model productions This paper presents an overview of this development.
Estimation of production rate in flexible assembly systems
H. Makino (1), M. Tominaga  
STC A,  44/1/1995,  P.7
Keywords: Assembly Machine, Flexibility, Productivity
Abstract : Production planning of a new product starts from the estimation of the production volume per month or per year. The construction of the standardized flexible assembly systems should be designed to satisfy the required cycle time. Because a flexible assembly system consists of several sub-systems such as feeding, transport, assembly and transfer ones, the total cycle time of the whole system depends upon the cycle times and repeating numbers of each operation. In this report the cycle time and the consequent production rate are estimated for typical flexible assembly systems. Each factor affecting the results is discussed.
Grouping of used products or cellular recycling systems
C. Hentschel, G. Seliger (2), E. Zussman   / E. Lenz (1)
STC A,  44/1/1995,  P.11
Keywords: Group Technology, Fuzzy, Disassembly
Abstract : This paper presents an approach to recycling system planning for used products at their end-of-life phase We focused on the design of cellular recycling systems by using group technology. Current approaches employ design and process attributes for group formation in manufacturing. The recycling process of a product, however, is characterized by uncertainties due to usage influences on the product. We introduce in this paper usage attributes in addition to those mentioned above. In order to consider the usage attributes, fuzzy-set theory is applied. The approach is illustrated by designing a cellular system for the recycling of Cathode Ray Tubes (CRT) from used monitors and TV sets.
A process model for elastomer-metal-pressfits
S. Neu, G. Seliger (2)  
STC A,  44/1/1995,  P.15
Keywords: Assembling, Modelling, Press
Abstract : This paper describes an analytical and numerical process model for elastomer-metal-pressfits. Based on the mathematical description of the fitting process, methods and experiments to identify the values of relevant process parameters are presented. Linear independence of process parameters is checked by statistical comparison. Besides analytical process description, numerical methods like Boundary Element Methods (BEM) are used. Sliding friction coefficients for a number of elastomer-metal-pressfits are examined experimentally. The results of the examination of all parameters and the general applicability of the model are discussed using the example of an elastomer-metal absorbing spring.
Direct soldering of electronic components on molded devices
K. Feldmann (1), M. Gerhard  
STC A,  44/1/1995,  P.19
Keywords: Soldering, Electronic, Quality assurance
Abstract : Using the great potential of the three-dimensional Molded Interconnect Devices (3-D MID) necessitates the adaption of the conventional soldering methods in electronic assembly. The different characteristics of the soldering technology determine the suitability of various engineering thermoplastics as substrate material. So several investigations on application of different thermoplastic materials have been carried out. Furthermore, the geometric design of the molded carriers and the impact on the temperature distribution on the board during the soldering process will be discussed and the possibilities and the limitations of conventional soldering equipment will be shown.
A cooperative assembly system using two manipulators with precise positioning devices
T. Arai (2), H. Osumi, T. Fukuoka, K. Moriyama  
STC A,  44/1/1995,  P.23
Keywords: Assembly, Cooperative Control, Robots
Abstract : This paper proposes an assembly system with double industrial manipulators. Each manipulator consists of precise and coarse positioning devices. Compliance is introduced to accommodate positioning errors between the double manipulators. A cooperative control scheme for the two manipulators is studied. The results of experiments verify the effectiveness of the proposed scheme. This system is well suited for assembly of large-sized parts.

 STC C 

Analysis of three dimensional burr formation in oblique cutting
M. Hashimura, K. Ueda (2), D.A. Dornfeld (2), K. Manabe  
STC C,  44/1/1995,  P.27
Keywords: Burr Formation Analysis, Cutting, Finite Element Method (FEM)
Abstract : The results of cutting experiments and computer simulation of oblique cutting conducted in order to understand three dimensional burr formation and the effect of the tool inclination angle are presented. Cutting experiments were carried out in a scanning electron microscope with a micro machining device. Two types of burr were observed: exit burr on the exit edge of the workpiece and side burr on the side of the workpiece. The exit burr in oblique cutting was smaller than in orthogonal cutting, while the side burr in oblique cutting was larger than its orthogonal counterpart. A three dimensional finite element method program was also developed to predict three dimensional burr formation. The simulation showed good qualitative agreement with experimental data on both burr shape and cutting forces.
Ultrasonic elliptical vibration cutting
T. Moriwaki (1), E. Shamoto  
STC C,  44/1/1995,  P.31
Keywords: Cutting, Ultrasonic Vibration, Ultraprecision Cutting
Abstract : A new cutting method named ultrasonic elliptical vibration cutting is proposed and applied to cutting of metals by utilizing a new vibrator to vibrate the cutting tool elliptically at ultrasonic frequency. It is confirmed experimentally that the cutting performance, in terms of the cutting force and the chip thickness, is improved significantly by applying the elliptical vibration to the cutting tool. The experimental results prove that the method can be applied to practical ultraprecision cutting of metals.
High speed milling of dies and moulds. Cutting conditions and technology
H. Schulz (1), St. Hock  
STC C,  44/1/1995,  P.35
Keywords: Milling, Tool, Wear
Abstract : Due to the high feed rates, high speed milling (hsm) provides a great potential of rationalization for machining free formed surfaces like dies and moulds. The knowledge of the cutting conditions is decisive for tool life and workpiece quality. By machining with ball end mills, unfavourable cutting conditions can be avoided by using a tilt angle. This paper gives a report on a geometrical model to describe the cutting process by using ball end mills with a tilt angle. Based on this theoretical model, wear process and optimized cutting conditions for high speed milling of free formed surfaces can be determined. Practical experiments confirm the model.
An improved model of the chip thickness in milling
S.A. Spiewak (2)  
STC C,  44/1/1995,  P.39
Keywords: Cutting, Milling, Predictive Maintenance
Abstract : A new class of comprehensive models proposed in this paper integrates and expands essential features of previously developed analytical and numerical models The employed systematic modeling methodology facilitates a stepwise and orderly increase of the model's sophistication until the desirable level of performance is achieved. Application of the developed class of models can lead to substantial improvement of the speed, accuracy and reliability of monitoring and control applied to the machine, tool and cutting process. The accuracy of representative models is compared under realistic machining conditions.
Computer-aided predictive cutting model for forces in face milling allowing for tooth run-out
E.J.A. Armarego (1), J. Wang, N.P. Deshpanede  
STC C,  44/1/1995,  P.43
Keywords: Modelling, Milling, Cutting
Abstract : In this paper the development of a predictive cutting model and software module for the average and fluctuating force components, torque and power in Face milling operations is outlined and discussed. The model, which is based on the mechanics of cutting approach and incorporates the many tool and cut process variables as well as the inevitable tooth run-out, has been assessed by numerical simulation and experimental testing. The model has been verified qualitatively and quantitatively and has highlighted the importance of the tooth run-out on the force fluctuations. This work provides a further step towards establishing machining on a sound scientific, predictive and quantitative basis.
A new parametric approach for the assessment of comprehensive tool-wear in coated grooved tools
I.S. Jawahir (2), P.X. Li, R. Ghosh, E.L. Exner  
STC C,  44/1/1995,  P.49
Keywords: Tool, Machining, Wear
Abstract : This paper presents a new methodology for evaluating tool-wear in grooved tool inserts, based on experimental analysis of chip flow Machining experiments using high speed filming techniques and scanning electron microscopy reveal the strong influence of chip-grove parameters on tool-wear. Four different grooved tool inserts, each with four different coatings, are tested under a wide range of cutting conditions A new tool life relationship, including the effects of chip groove parameters and tool coatings, has been developed and validated for a range of machining conditions on steel 1037M work material.
Improvement of tool life through variable feed milling of Inconel 600
M. Balazinski, V. Songméné   / L. Kops (1)
STC C,  44/1/1995,  P.55
Keywords: Feed, Tool, Wear
Abstract : A new approach for improving the cutting tool life by varying the feed throughout the cutting process has been developed at Ecole Polylechnique de Montreal. This paper presents the study leading to the selection of the optimal feed variation parameters for the face milling of Inconel 600. The experimental results indicate that the most influential factors are the amplitude and duration of each feed variation step. A ten percent sinusoidal feed variation cycle about the optimal feed, with five seconds incremental steps, increases the cutting tool life by a minimum of 30 percent. The comparison was based on a constant material removal rate.
Real-time tool breakage monitoring for NC milling process
J.M. Lee (1), D.K. Choi, J. Kim, C.N. Chu  
STC C,  44/1/1995,  P.59
Keywords: Milling, Fracturing, Detecting
Abstract : This paper presents real-time tool breakage detection in NC milling process by monitoring cutting force. Cutting force was indirectly measured by the feed drive AC motor current. Modeling of the feed drive system and calibration with a tool dynamometer show that the sensitivity of the feed drive motor current is sufficient to characterize tool breakage. AR 1 model with tool-runout is used to determine tool breakage. 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.
The energy quanta and the entropy - New parameters for identification of the machining processes
J. Peklenik (1), S. Dolinsek  
STC C,  44/1/1995,  P.63
Keywords: Identification, Energy Quanta, Entropy
Abstract : The contribution presents some new findings in search for a more comprehensive description of the machining processes, such as turning, milling and drilling. The experimentally determined power spectra of the input, transformation and output energy are used for computing the energy quanta and the entropy of the processes. It is shown, that the change of the entropy allows to explain some of the process behaviours. By introducing the energy quanta, as a derivative of the energy power spectra, a new parameter has been confirmed which contributes to better understanding of the machining process physics.
On a thermo-mechanical model of shear instability in machining
Z.B. Hou, R. Komanduri (1)  
STC C,  44/1/1995,  P.69
Keywords: Machining, Cutting, Shear
Abstract : Shear instability was observed experimentally in machining some of the difficult-to-machine materials, such as hardened alloy steels, titanium alloys, and nickelbase superalloys yielding cyclic chips. Recht in 1964 developed a classical model of catastrophic shear instability in machining. In this investigation, based on the analysis of cyclic chip formation in machining, possible sources of heat (including preheating effects by these heat sources) contributing toward the temperature rise in the shear band were identified. The temperature rise was calculated using Jaeger's classical solutions of stationary and moving heat sources. Recht's original catastrophic shear instability model for shear localization was extended by predicting analytically the conditions for the onset of shear localization.
Optimization of tangential tool shift in gear hobbing
K.D. Bouzakis (1), A. Antoniadis  
STC C,  44/1/1995,  P.75
Keywords: Hobbing, Gear, Wear, Optimization
Abstract : Gear hobbing is an efficient method of gear manufacturing. Due to the fact that during the cutting process, every hob tooth always cuts in the same generating position, where the formed chip has different geometry, the resulting tool wear is not uniform on any particular hob tooth. In order to overcome this problem, the hob is shifted tangentially after a certain number of cuts. The optimum selection of the shift displacement and the number of gears (shift amount), after which the hob has to be shifted, leads to a uniform tool wear and consequently increases the amount of the hobbed gears per tool regrinding, until the maximum permitted tool wear is reached. In the present paper, an experimentally verified computational procedure is presented, which enables the determination of optimum values for the shift displacement and for the corresponding shift amount, by considering the wear behaviour of the hob teeth in the individual generating positions.
Mathematical model for the establishment of the materials machinability
S. Enache (1), E. Strajescu, C. Opran, C. Minciu, M. Zamfirache  
STC C,  44/1/1995,  P.79
Keywords: Machinability, Mathematical Model, Titanium Alloys
Abstract : This paper presents a new mathematical model for the establishment of the partial and global machinability. The model is basal on the evaluation criteria of the material's machinability and permits the establishment of the best material, who can be utilised from the point of view of the machinability. Also, it permits the establishment of the machining condition regarding cutting process, at wich the machinability is optimal from the point of view of the productivity and of the economic efficiency. Are shown, the results of the experimental researches in the case of titanium alloys cutting with turning tools.

 STC Dn 

Computer-aided optimal design strategy of power transmission systems
B. Kaftanoglu (1), E. Ulugül, N. Carkoglu  
STC Dn,  44/1/1995,  P.83
Keywords: CAD, Design, Optimization
Abstract : A mechanical power transmission system consists of mainly shafts, gears and bearings, where each machine element can be optimally designed. However in a power transmission system each design variable such as pitch diameters of gear and diameters of bearings have certain constraints. These constraints effect the design of the other member like the shaft. A design strategy is developed for the optimal integrated design of a mechanical power transmission system including the constraints of each member and with the view to satisfy a global optimum for the system.
Light robot arm based on inflatable structure
N. Salomonski, M. Shoham (2), G. Grossman  
STC Dn,  44/1/1995,  P.87
Keywords: Robot, Flexible, Mechanism
Abstract : This paper deals with a new kind of mechanical structure for robotic arm based on elements made of thin, inflatable shells. This approach offers the advantage of increasing the strength-to-weight ratio of the robot. Moreover, it allows compact packaging and ease of robot deployment, critical in hard-to-reach spaces, where volume and weight are of utmost importance. In addition, the robot is safer due to less damage in case of collision. At this work we test the feasibility of using that new kind of mechanical structure to a practical implementation, by simulation and by operative experiment.
An intelligent object oriented approach to the design and assembly of press tools
H.S. Ismail, K.K.B. Hon (2), K. Huang  
STC Dn,  44/1/1995,  P.91
Keywords: Design, Expert Systems, Object Orientation
Abstract : In recent years, research communities and industries have started to develop knowledge-based tooling design systems to tackle the common difficulties that most companies have. The most widely used strategy is accommodating the know-how into an expert system and linking it with a CAD system This paper describes the structure and operation of a prototype intelligent system for progressive die design and manufacturing. The system is developed using X Window C programs to create the interface linking the CAD package, AutoCAD, and the expert system shell, Kappa. AutoCAD is used for the input of the piece part geometry, creating the temporary drawings and final design drawings of the tool parts and assembly. Kappa is used to create the knowledge base, the databases of the standard tool parts, and the menu system for entering design data. C programs are also used for some intensive computations, for example, calculating the best material utilisation.
Guaranteeing manufacturability of CSG operations
W.A.H. De Vries, F.L.M. Delbressine, A.C.H. Van Der Wolf (1)  
STC Dn,  44/1/1995,  P.97
Keywords: Modelling, Computer Aided Design (CAD), Computer Aided Process Planning (CAPP)
Abstract : The paper deals with the integration of design, process planning and manufacturing using Constructive Solid Geometry (CSG) design operations. This integration is achieved by mapping CSG design operations onto manufacturing operations. The mapping is realised such that the manufacturability of the current design can be guaranteed while designing and that a right-first-time production can be realised. Especially the mapping of the CSG operator "unite two solids" onto the material removal manufacturing technique milling will be dealt with extensively in this paper. The chosen approach is described and explained using an example.
An interaction mechanism for 3D object-oriented feature-based models in interactive design and simulation
A. Fischer, K.K. Wang (1)  
STC Dn,  44/1/1995,  P.101
Keywords: Feature, Object Oriented Programming, CIM
Abstract : In engineering applications such as interactive design and simulation, some of the main object manipulations include feature interaction. Today's CAD systems provide object oriented structures which can explicitly represent functional and geometrical interactions among features. However, conventional interaction algorithms for manipulating these structures cannot cope with non-geometrical information such as feature functionality. Interaction among features plays an essential role in defining functionality. In this paper, a new method is described which focuses on implementation of an interaction mechanism for design and simulation. Two interaction categories are handled: (1) neighbouring interaction, which is primarily geometrical (blending and trimming) and (2) functional interaction (machining). Since most interactions are performed in a sub-domain rather than in the entire domain, the advantage of the locality property is considered in both cases.
On the support of design process management in integrated design environment
W.J. Zhang, C.A. Van Luttervelt (1)  
STC Dn,  44/1/1995,  P.105
Keywords: Design Process, Management, Computer-Aided Design
Abstract : The computer-aided design process management is noticed as an intelligent feature of modern integrated CADCAM systems. This paper addresses this problem in the context of developing an integrated software environment for designing and manufacturing of mechanical systems. Emphasis is placed on the discussion of the design process management concepts and computer (or data) model which structures and represents various kinds of design process related information An experimental implementation for CADCAM of compound cam mechanisms has been made, which gives verification of the idea.
Active data driven design using dynamic product models
D.S. Domazet, F.N. Choong, D. Sng, N.C. Ho, S.C.Y. Lu (2)  
STC Dn,  44/1/1995,  P.109
Keywords: Product Development, Product Modelling, Concurrent Engineering
Abstract : In this paper a new approach to event-driven product design is proposed. It is based on active data of dynamic product models. The dynamic product model contains ECA (Event-Condition-Action) rules that trigger execution of tasks or propagate updates to the product data. When certain states of the product design are reached, new design tasks are initiated or a new product model state is automatically reached as the result of a design change propagation. This approach is very suitable for concurrent engineering where the order of design tasks can not be specified in advance. Dynamic product models are stored in an object-oriented database system accessible by all concurrent engineering participants through a software layer that manages the ECA rules. Syntax for the ECA rules and their use in driving concurrent engineering are proposed in this paper.
Representing background information for product description to support product development process
F. Kimura (2), H. Suzuki  
STC Dn,  44/1/1995,  P.113
Keywords: Design, Product Development, Product Modelling
Abstract : This paper describes an attempt to capture and to represent product information, which is used for generating product definition, but is not explicitly represented in product description. In this paper, such information is called background information. It includes requirements, specifications, assumptions, constraints, decision history, trial-and-error processes, and "rationale" in general. It plays an important role by providing information about underlying reasoning for product development. The information is to be captured by interaction with practical design processes, and to be represented by a structural framework based on an object oriented approach.
Facility model for life cycle maintenance system
S. Takata (2), H. Hiraoka, H. Asama, N. Yamaoka, D. Saito  
STC Dn,  44/1/1995,  P.117
Keywords: Computer Models, Maintenance, LifeCycle
Abstract : For bringing out full capabilities of manufacturing facilities, various maintenance activities are necessary throughout the facility life cycle from design to the end of its life We have been proposing the necessity of a support system for achieving efficient and consistent life cycle facility management based on a facility model In this paper, the structure of the facility model is presented. The model can represent the hierarchical structure of facilities. It also provides flexible means to represent various technical information relevant to the facility management. The effectiveness of the model is shown by a deterioration evaluation system of the facility.
Actual conceptual design process for an intelligent machining center
Y. Hatamura, T. Nagao (2), M. Mitsuishi, M. Nakao  
STC Dn,  44/1/1995,  P.123
Keywords: Conceptual Design Process, Intelligent Machining Center
Abstract : The conceptual process in design proceeds in the order "Performance Mechanism Structure;" and advances through "Application and Evaluation" in what may be thought of as a conceptual development spiral. In actual designs, these spirals are repeated and the process proceeds in the order "Conceptual sketch- Plan drawing-Final plan drawing." Progress in the conceptual process corresponds to equivalent progress in the detail design operation. "Eight design principles for machines" and "Six design principles for intelligent manufacturing systems" are proposed. By using these principles, a fundamental structure for intelligent manufacturing systems is established and applied to the design of an intelligent machining center that has been built and tested. Testing and evaluation of the machining center that was developed verified the validity and the effectiveness of the proposed concepts.
A proposal to a product modelling language to support conceptual design
K. Andersson, p. Makkonen, J.G. Persson (2)  
STC Dn,  44/1/1995,  P.129
Keywords: Conceptual Design, Design Language, Mechanisms
Abstract : Computer aid for conceptual design has so far only been available for some specialized domains. The main reason for this is that conceptual design work is a very complex process that is difficult to represent in computer models. One approach to support this type of design work is the CANDLE modeling language which enables the use of engineering terminology for modeling early design work. This paper describes a further development of the CANDLE modeling language in order to support the early design phases of mechanisms and manipulator systems. This can be accomplished by expanding the basic taxonomies of engineering terminology with physical and solution principles that are specific for design of mechanisms and manipulator systems.
A new interface for conceptual design based on object reconstruction from a single freehand sketch
H. Lipson, M. Shpitalni (1)  
STC Dn,  44/1/1995,  P.133
Keywords: CAD, Conceptual Design, Interface
Abstract : A new system has been developed for improving user interaction with CAD systems, particularly in the conceptual design stage. The system is based on interactive, part-by-part formation of a geometrical model using freehand sketching. A single 2D inaccurate projection is entered in the form of a line drawing. The system analyzes and interprets the input and then reconstructs a 3D model of the object most likely to be represented by the sketch. This 3D model can be further manipulated or modified, and more parts can be sketched. This approach provides a fluent and intuitive tool for conceptual design. In the paper, the proposed system is presented and the basic ideas are discussed and exemplified.
Conceptual Modelling for Industrial Design
F.-L. Krause, J. Lüddemann, A. Striepe  
STC Dn,  44/1/1995,  P.137
Keywords: Conceptual Product Design, Interactive Industrial Design System, Geometric Modelling
Abstract : Conceptual product data in packages, digital mock-ups or layout plans are the basis for designing the shape of a product. A system approach is presented which allows for the incorporation of these restrictive data in an appropriate manner for computer-aided styling tasks. The highly interactive and easy-to-use system components support the abstraction, modification and verification of conceptual data for preparation as well as the creative and intuitive modelling of three dimensional shapes. Characteristic of the new modelling approach is the strong analogy with the traditional, still predominant clay modelling process in the field of industrial design.

 STC E 

Pulsed laser materials processing, ND-YAG versus CO2 lasers
F.O. Olsen   / L. Alting (1)
STC E,  44/1/1995,  P.141
Keywords: Laser, Welding, Cutting
Abstract : Pulsed laser materials processing is widely applied in fine cutting, welding and hole drilling. In this paper pulsable C02-lasers and ND-YAG-lasers are compared for pulsed laser cutting, welding and hole drilling. In laser cutting the performance of a superpulsed C02-laser in Aluminium cutting is described and compared to typical ND-YAG-laser cutting data. In pulsed laser welding, experimental investigations in welding AISI 316 stainless steel, where hot cracking sensitivity has been addressed, applying a ND-YAG laser and a superpulsed C0_2 -laser, will be described. Finally metal, polymer and ceramics laser drilling applying different C0_2 -lasers will be described and compared to ND-YAG-laser performance.
About the application of fuzzy controllers in high-performance die-sinking EDM machines
M. Boccadoro, D.F. Dauw (2)  
STC E,  44/1/1995,  P.147
Keywords: EDM, Die Sinking, Fuzzy control
Abstract : The paper deals with the problematics of die-sinking optimization and control systems As it is known, Electric Discharge Machining is partly stochastic in nature In the past, various optimization control algorithms have been developed and implemented to improve the overall performance of EDM die sinkers. AGIE has introduced Adaptive Control Optimization (ACO) algorithms as well as Adaptive Control Constraint (ACC) regulators To satisfy the customers requirements even better, new techniques have been studied, and the use of fuzzy controllers is now reality In the paper, a description of fuzzy controllers is given, its principles and results on commercial EDM AGIE die sinkers It is proven that in comparison with traditional controllers, fuzzy regulators are definitely well suited in an EDM environment.
Recent developments in laser system tehnology for welding applications
P. Hoffmann   / M. Geiger (1)
STC E,  44/1/1995,  P.151
Keywords: Laser, Welding, Quality Assurance
Abstract : Further spreading of laser welding technology essentially needs an improvement of the reliability of the welding systems and an enlargement of applicability even at complicated workpiece structures. With this paper measures are proposed in order to meet these goals: - stabilization of the laser source by a closed loop control of the laser power - optimization of the laser beam guiding and forming by use of Adaptive Optics.
Benchmarking of rapid prototyping techniques in terms of dimensional accuracy and surface finish
R. Ippolito (1), L. Iuliano, A. Gatto  
STC E,  44/1/1995,  P.157
Keywords: Rapid Prototyping, Accuracy, Roughness
Abstract : Dimensional accuracy and surface finish are the cornerstone of Rapid Prototyping (RP) especially if the models will be used for the production of tools as mould or EDM electrodes. The paper deals with the development, manufacture and testing of benchmark to investigate dimensional accuracy and surface finish. A new technique of checking the machine quality of a RP workpiece according to the ANSI-ISO standards is presented. Moreover the surface of RP model were observed by SEM microscope.
Surface modification of steel by a small diameter plasma arc
T. Miyazaki, S. Yoshioka, T. Kimura, A. Komatsu, N. Kinoshita (1)  
STC E,  44/1/1995,  P.161
Keywords: Plasma, Hardening, Alloy
Abstract : A plasma arc, which is produced through a small diameter nozzle, is applied to surface modification of steel. The nozzle diameters are 0.2 and 0.3 mm; the arc diameter is so small that the power density is of the order of 10^6 W/cm2. This is applicable to small area surface modifications. In case of surface hardening due to self-quenching, Vickers hardness of 1000 is obtained for AISI 1045; melting does not occur. In case of alloying with SIC particles, Vickers hardness of 1200 is obtained for AISI 1010; furthermore, the wear resistivity is increased by a factor of several tens.
Electrode wear process in electrical discharge machining
N. Mohri, M. Suzuki, M. Furuya, N. Saito   / A. Kobayashi (1)
STC E,  44/1/1995,  P.165
Keywords: Electrical Discharge Machining, Electrode, Wear
Abstract : This paper deals with a synthetic consideration of electrode wear phenomena in electrical discharge machining. Time dependence of an electrode shape was observed through on-the-machine measurement. While the electrode wears at the edge portion in the beginning of machining, it grows at the flat portion in the longitudinal direction. In the stationary state of machining, the wear rate of an electrode is affected by the materials of work piece. Taking account of the precipitation of turbostratic, carbon on the electrode, the presence of catalyst in the work piece material is considered. The turbostratic carbon on the surface of electrode prevents the electrode from spark erosion in EDM.
Study of the white layer of a surface machined by die sinking Electro Discharge Machining
J.P. Kruth (1), L. Steven, L. Froyen, B. Lauwers  
STC E,  44/1/1995,  P.169
Keywords: Electro Discharge Machining (EDM), Surface Integrity
Abstract : Electro discharge machining (EDM) causes a white layer at the surface of a workpiece. The research work, described in this paper, aims to acquire a profound knowledge of this layer. The influence of workpiece material, electrode material and type of dielectric on the composition and the metallographic phases of the white layer is discussed. The measurements yield that the use of an oil dielectric increases the carbon content in the white layer. A water dielectric on the other hand, causes a decarbonisation. The carbon in the white layer machined in an oil dielectric appears as iron carbides (Fe3C) in columnar, dendritic structures. This is a result of the very rapid re-solidification of the molten material. In between the carbide dendrites, rest austenite and also some ferrite can be found.
Modular method for microparts machining and assembly with self-alignment
H.H. Langen, T. Masuzawa (1), M. Fujino  
STC E,  44/1/1995,  P.173
Keywords: EDM, Micromachining, Assemblies
Abstract : A low-cost prototype has been developed for modular machining and assembly of 3D microparts with self-alignment Microparts and/or their microtools were machined and temporarily stored in a mini-worktable of a MMA (modular machining assembly) unit where further machining and/or (sub)assembly techniques were applied WEDG (wire electrodischarge grinding), micro-EDM and reverse micro-EDM were used for material machining, and additionally enabled automatic microparts alignment for further assembly purposes Ultrasonic vibration was applied during (micro)parts assembly. The machining and assembly of a micropipe and macrocylinder combination is given as a fabrication example.
Modelling and monitoring interelectrode gap in pulse electrochemical machining
K.P. Rajurkar, B. Wei, J. Kozak, J.A. McGeough (1)  
STC E,  44/1/1995,  P.177
Keywords: Electrochemical Machining, Modelling, Accuracy
Abstract : Pulse electrochemical machining (PECM) provides an economical and effective method for machining high strength, heat resistant materials into complex shapes such as turbine blades of titanium alloys. The dimensional accuracy of PECM can be improved if a small interelectrode gap is maintained. This paper presents an interelectrode gap model for estimating machining parameters for the minimum gap size under the limit of electrolyte boiling A specially-built PECM cell and a high speed data acquisition system are used to acquire the pulse current signal for developing a non-line monitoring strategy. A stochastic analysis of the current signal indicates a linear correlation between the gap size and the variance of the filtered current signal. An on-line monitoring system based on this correlation is proposed for the PECM process.
On-line monitoring of the solidification front in metal casting
J.H. Chun, R.C. Lanza, N. Saka, M.M. Hytros   / N.P. Suh (1)
STC E,  44/1/1995,  P.181
Keywords: Casting, Control, Sensor
Abstract : In the continuous and semi-continuous casting of metals and alloys, the shape and location of the solidification front greatly affect the quality of castings. Yet, there is no real-time sensor available to the casting industry for monitoring the solidification front. A recently invented three-dimensional imaging technique for tracking the liquid/solid interface in the solidifying casting is presented. Issues involved in the application of the technique to the feedback control of continuous casting processes are also addressed.

 STC F 

Some applications of the Barlat 1991 yield criterion
F.A.C.M. Habraken, J.H. Dautzenberg (2)  
STC F,  44/1/1995,  P.185
Keywords: Aluminium, Yield, Anisotropy
Abstract : Nowadays the accuracy of (FEM) analyses of forming processes is to a large extent determined by the assumption of realistic constitutive equations for the description of the material and its interface with tooling/ Concerning aluminium alloys there are reasons for attention to the first topic these alloys often show significant anisotropy and in general have the reputation of being troublesome in analyses of forming processes. Through some applications, it will be shown that a yield criterion proposed by Bbarlat t al. (1991) gives good results. Last criterion is based on the generally accepted framework of a yield surface and associative flow. It thereby preserves simple operational use.
The inverse approach for the determination of constitutive equations in metal forming
J.C. Gelin (1), O. Ghouati  
STC F,  44/1/1995,  P.189
Keywords: Identification, Material, Finite Element Method
Abstract : An inverse identification method for material parameters estimation is proposed in this paper. This method allows an accurate identification by avoiding the usual assumptions made in order to convert experimental measures into constitutive variables. A sensitivity analysis is developed to evaluate the effect of parameters variations on the material response. This analysis is based on a direct differentiation method allowing an accurate sensitivity determination with a low computational cost compared to a finite difference method. This inverse identification procedure is applied to the determination of the viscoplastic behaviour of aluminium alloys in hot working using both the plane strain compression test and the axisymmetric compression test. The results obtained with both tests are the same.
An explicit model for the thermal-mechanical analysis of hot metal forming processes
F. Micari (2), L. Fratini, N. Alberti (1)  
STC F,  44/1/1995,  P.193
Keywords: Hot, Forming, FEM
Abstract : In the paper the authors propose a new finite element code for the coupled thermal-mechanical analysis of hot metal forming processes. As regards the mechanical problem, an explicit algorithm based on the solution of the dynamic equilibrium equation and an explicit time integration scheme is used, while the heat transfer analysis is based on the solution of the thermal equilibrium equations; in order to put the thermal problem in an explicit linear form a three level scheme has been employed for the discretization of the time variable. The model is based on a staggered procedure, in which the mechanical and the thermal analysis are carried out with respect to different time horizons; in fact while the analysis of the mechanical problem is performed increasing the velocity of the process, as it is usual when an explicit formulation is used, such an artifice cannot be accepted for the thermal problem which is strongly time dependent.
Fractal geometry used for the characterisation of sheet surfaces
E. Doege (1), B. Laackman, B. Kischnick  
STC F,  44/1/1995,  P.197
Keywords: Sheet Metal, Surface, Friction
Abstract : Common technical roughness parameters are not able to characterise technical surfaces clearly. Only the specification of additional parameters may allow a statement about the surface character. Based on the Weierstiraß-Mandelbrot function a fractal model for the characterisation of surface profiles was developed. Only two parameters are needed to distinguish different surfaces. Thereby a surface profile is measured by means of a surface profiler. To find a suitable fractal description for a given surface, the power spectra of the function and the empirical data are used. Afterwards the empirical power spectrum is interpreted as the power spectrum of a Weierstiraß-Mandelbrot fractal function with fractal parameters to be determined. Additionally this technique also allows the qualitative reconstruction of a previously measured profile. Series of measurements using the materials X5 CrNi 1810, St12 03, and A/Mg3 proved the model to be well applicable to sheet surfaces. Investigations were carried out in order to verify the influence of parameters relevant for sheet metal forming on the fractal model.
Evaluation of temperature and heat transfer conditions at the metal forming interface
W. Nshama, J. Jeswiet (2)  
STC F,  44/1/1995,  P.201
Keywords: Forming, Heat Transfer
Abstract : This work is part of an on-going study of the physics of the die-workpiece interface in metal forming. An experimental investigation has been conducted on the temperatures at the interface in metal forming. This work differs from others in that the temperatures are measured directly at the die-workpiece interface. The raison d'être for this work is the experimental data from these measurements can be used to derive accurate heat transfer coefficients (thermal resistances). For the experiments in this work two flat platens were used as dies with both hot and cold solid cylindrical billets. The results indicate that this method can provide a reliable means of predicting the contact resistance.
Low-speed mixed lubrication of metal forming processes
W.R.D. Wilson   / S. Kalpakjian (1)
STC F,  44/1/1995,  P.205
Keywords: Tribology, Lubrication, Metal Forming
Abstract : In the mixed lubrication regime, part of the interface load is carried by asperity contact and part by the pressurized lubricant in surface valleys. Under high-speed conditions, the lubricant is pressurized by wedge action in the inlet zone which lies upstream of the work zone. However, even under low speed conditions, where the inlet zone is inactive, significant lubricant pressures can be generated by wedge action in the work zone. The wedge is due to the reduction in average film thickness created by progressive asperity flattening as plastic deformation proceeds.
Direct observation of contact behaviour to interprete the pressure dependence of the coefficient of friction in sheet metal forming
A. Azushima   / H. Kudo (1)
STC F,  44/1/1995,  P.209
Keywords: Drawing, Friction, Lubrication
Abstract : In a previous work, for the determination of the relationship between coefficient of friction and contact pressure to be used in the numerical process simulation, the author found experimentally that the coefficient was constant in the lower pressure range, whilst over 0.3 s , it decreased with increasing pressure. In the present work, a flat tool drawing apparatus which consists of a transparent die of quartz, a microscope with a CCD camera and a video system is developed to observe in situ the contact behaviour at the interface directly. Thus, the lower average pressure regime is characterized by isolated contact zones, while the higher pressure regime by oil pockets and oil permeation into the contact zone Based on this lubricant mechanism, the above relationship can be qualitatively interpreted.
Tribology during hot, flat rolling of steels
P. Munther, J.G. Lenard (1)  
STC F,  44/1/1995,  P.213
Keywords: Friction, Rolling, Metal
Abstract : Tribology, defined to include the transfer of heat and forces at the surface of contact, is studied. The parameters affecting hot tribology are presented and discussed. An optical technique is used to monitor the forward slip during hot rolling, in air, of low carbon steel slabs. The forward slip is then related to the coefficient of friction by a finite element method. While previously published data indicate that the coefficient of friction increases, decreases, reaches a plateau before falling or remains steady with increasing temperatures, the current results clearly show that m decreases with temperature and increases with load. The coefficient of heat transfer is also strongly dependent on the process parameters. The data is used to shed new light on roll wear.
A new friction and lubrication test for cold forging
N. Bay (2), O. Wibom, J. Aa. Nielsen  
STC F,  44/1/1995,  P.217
Keywords: Forming, Friction, Lubrication
Abstract : This paper presents a new friction and lubrication test for cold forging The test allows controlled variation of the surface expansion in the range 0-2000%37;, the tool temperature in the range 20-270°C and the sliding length between 0 and infinite. Friction is decreasing with increasing temperature in the range 30-150°C. Above this temperature range friction increases. As regards lubricant performance Lubrication Limit Curves (LLC) are plotted in a sliding length-surface enlargement diagram with the tool temperature as a parameter. Larger tool temperature implies lower acceptable surface expansion and sliding length.
FEM simulation of hot forging with dynamic recovery process
S.I. Oh (2), S.H. Im  
STC F,  44/1/1995,  P.223
Keywords: Finite Element Method, Forming
Abstract : In metal deformation at elevated temperature, the strain hardening produced by the deformation tends to counteracted by dynamic recovery, and strain cannot be a proper variable to represent flow stress under this condition. In order to take into account the dynamic recovery process, constitutive equation should include a state variable which represents the internal microstructure. In this paper, FEM formulation has been established to accommodated the dynamic recovery process. Then non-isothermal simple compression processes by mechanical press and hammer were simulated. The results were compared to those by the conventional flow stress representation.
Preform design for forging rotationally symmetric parts
F.H. Osman, A.N. Bramley (1)  
STC F,  44/1/1995,  P.227
Keywords: Forging, Upper Bound, Simulation
Abstract : This paper describes an upper bound modelling based technique to design preforms for forging of rotationally symmetric parts. A reversing algorithm which results in improved metal flow in the final stages of filling the cavity is applied to the precision forging of bevel gears. The predicted preform has a simple rotationally symmetrical profile which accommodates the simultaneous filling of the gear teeth. Experimental results show that the preform designed by this technique requires less energy in the final stages of the forging.
Life estimation of extrusion dies
A.E. Tekkaya, A. Sonsöz   / K. Lange (1)
STC F,  44/1/1995,  P.231
Keywords: Fatigue-Crack, Extrusion-Dies
Abstract : The fatigue behaviour of cold extrusion dies is investigated The effective stress intensity factor at different locations of the die inlet of a typical axisymmetric extrusion die has been calculated by the finite element code method Applying the Paris/Erdo?an fatigue law to this calculated data, the crack growth has been simulated. From the crack-growth-rate the life of the extrusion die has been estimated. The agreement with the experimental results is satisfactory within the limits of experimental uncertainties. Furthermore, the experimentally observed behaviour of the crack growth, i. e stable-instable-stable growth with final fracture, is simulated perfectly.
Axial-radial forming of tubular components
D. Schmoeckel (1), F.D. Speck  
STC F,  44/1/1995,  P.235
Keywords: Process, Simulation, Tube
Abstract : The axial-radial forming process was developed at the Technical University of Darmstadt, combining elements of upsetting and rotary swaging. The process permits to produce defined thickness increases on tubular components, such as required for instance for the bearing seats of a transmission shaft. Axial-radial forming is performed on a modified rotary swaging machine additionally equipped with an upsetting unit and a heating station. The principle of the process will be presented and examples for the application potential will be shown. Parallely to the experimental research the process has been simulated with the finite-elements method.
Computerized numerical simulation of roll-forming process
M. Kiuchi (1), K. Abe, T. Onodera  
STC F,  44/1/1995,  P.239
Keywords: Roll, Forming, Simulation
Abstract : A computerized numerical simulation system for mid roll-forming was developed. It was applied to various roll-forming processes of ERW (electric resistance welded) pipes, light gauge section steels, deck-plates and others. Through simulations, effects of pass-schedule, geometry and position of roll, dimension of product and mechanical properties of metal sheet on deformation features of metal sheet at every forming stage, stress and strain occurring in it, roll separating force, roll driving torque and dimensional accuracy of product were clarified. The system is now being used for design and prediction of desirable profiles of forming rolls, roll positions and other operation factors. It is also being successfully used to design pass-schedules for newly requested products.
Controlled FEM simulation for determining history of blank holding force in deep drawing
K. Osakada (1), C.C. Wang, K.I. Mori  
STC F,  44/1/1995,  P.243
Keywords: Deep Drawing, Finite Element Method (FEM), Control
Abstract : To fully utilize the recent deep drawing machines with variable blank holding force, a method for determining an optimal history of the blank holding force is proposed. In this approach, a proper force which does not cause wrinkling and localized thinning is searched for at each deformation step by the finite element method. The result is supplied to the actual drawing machine. The effectiveness of the present method is demonstrated by the experiments of axisymmetric deep drawing with the so obtained history of blank holding force for aluminium sheets.
Control of blank holder force to eliminate wrinkling and fracture in deep drawing rectangular parts
M. Ahmetoglu, T.R. Broek, G. Kinzel, T. Altan (1)  
STC F,  44/1/1995,  P.247
Keywords: Deep Drawing, Wrinkling, Fracture
Abstract : The predominant failure modes In stamping of sheet metal parts (deep drawing and stretch forming) are wrinkling and fracture. In many cases these defects may be eliminated by appropriate control of the Blank Holding Force (BHF). This paper summarizes the results of a recent study on the formability of rectangular parts from aluminum alloy 2008-T4. Wrinkling and fracture limits have been determined and BHF control methods have been developed to eliminate defects, improve part quality, and increase the draw depth.
Closed loop control system for blankholderforces in deep drawing
K. Siegert (2), E. Dannenmann, S. Wagner, A. Galaiko  
STC F,  44/1/1995,  P.251
Keywords: Forming Press, Hydraulic Equipment, Control System
Abstract : When drawing non-axissymmetric sheet metal parts it is necessary to control the flow of material between the lower and upper binder in such a manner that prevents the occurrence of both tears and wrinkles in the drawn part. One possibility for the control of the material flow is through the deliberate adjustment of the normal forces. If one can measure the flow-in of the material in the die as a function of punch penetration with a special sensor, and if this information can be used to produce an average empirical desired flow-in curve, then with the implementation of modern hydraulic drawing facilities in the press table and/or the implementation of special dies with hydraulically supported segmented binders it is possible to build a closed-loop control system which allows for the automatic response of the drawing facilities or the hydraulic systems of the drawing die in light of changing friction conditions.
Investigation into manufacturing of very long cups by hydromechanical deep drawing and ironing with controlled radial pressure
D.Y. Yang (2), J.B. Kim, D.W. Lee  
STC F,  44/1/1995,  P.255
Keywords: Deep Drawing, Finite Element Method, Ironing
Abstract : High-quality cups of deep drawing ratio of more than four cannot be simply drawn by conventional drawing and redrawing process. In the present study, after the first deep drawing process, subsequent hydromechanical reverse redrawing with controlled radial pressure and final ironing to control the thickness and outer surface appearance are employed. In order to increase the deep drawing ratio much more than four, the radial pressure is controlled independently of the chamber pressure and thus an optimum forming condition can be found by varying the radial pressure. The final ironing process ensures the fine surface quality as well as improved deep drawing ratio without inducing any forming defect such as slight puckering and surface waviness. The process has been subject to finite element analysis by using the rigid-plastic material modeling considering all the frictional conditions induced by the hydrostatic pressure. The comparison of the computation with the experiment has shown that the finite element modeling can be conveniently employed for the design of the process with reliability from the viewpoint of formability.
Reduction of the residual stresses in a deep drawn cup by modifying the draw die profile
J. Danckert (2)  
STC F,  44/1/1995,  P.259
Keywords: Deep Drawing, Residual Stress, FEM
Abstract : Cylindrical deep drawing has been simulated using the FEM-code Dyna2D and has been analysed experimentally. The FEM simulations show that the residual stresses in the cup wall are mainly caused by the unbending of the material when the material leaves the draw die profile. FEM simulations show that by modifying the draw die profile in such a way that the unbending occurs gradually instead of instantaneously as in conventional deep drawing, a substantial reduction of the residual stresses can be achieved. The modified draw die profile also leads to a substantial improvement in the dimensional accuracy of the deep drawn cup. The experimental findings are in close agreement with the results obtained using FEM.

 STC G 

Subsurface evaluation of ground ceramics
B. Zhang, T.D. Howes (2)  
STC G,  44/1/1995,  P.263
Keywords: Ceramics, Grinding, Damage, Diamond
Abstract : Subsurface damage evaluations are performed using a combination of scanning electron microscopy and damage inspection techniques on silicon nitride, alumina, and silicon carbide ground by diamond wheels with various grit sizes. Two forms of subsurface damage are identified, material pulverization in the superficial layer forming a powder regime and void generation in the subsurface layer. Both forms of damage are assessed and characterized with respect to type of workpiece material and grit size of grinding wheel. The penetration depth of subsurface damage is shown to be predictable using an analytical model.
Energy partition to the workpiece for grinding of ceramics
B. Zhu, C. Guo, J.E. Sunderland, S. Malkin (1)  
STC G,  44/1/1995,  P.267
Keywords: Grinding, Ceramic, Temperature
Abstract : An investigation is reported of the energy partition to the workpiece for grinding of silicon nitride with diamond wheels The energy input to the workpiece was obtained by measuring the temperature response in the subsurface using a two-color infrared detector and matching the results to analytically computed values Temperature measurements obtained with a two-color detector should be independent of the emissivity of the workpiece material, which is an important advantage over a single-color detector. Measured temperature responses were in good agreement with analytical predictions for a moving heat source with a triangular distribution at the grinding zone. It was found that about 16 to 24%37; of the energy is transported as heat to the workpiece for wet grinding and 59%37; for dry grinding.
Chipping in high-precision slot grinding of Mn-Zn ferrite
Y. Ohbuchi, T. Matsuo (1), M. Sakata  
STC G,  44/1/1995,  P.273
Keywords: Grinding, Electronic Ceramic, Micro-Fracturing
Abstract : High-precision slot grinding was carried out on Mn-Zn ferrites to investigate the chipping mechanism and optimum slotting condition by measuring the chipping size at the slotted edges. The slot grinding was performed using a high-precision slicing machine with an air spindle and different type of 2mm wide diamond wheels. The size (width, length) of all chippings was measured by a specially designed form tracer with a knife edge pickup. Grinding forces were also measured. It is evident that chipping size depends on removal per grain and some ductile fracture modes are observed at lower removal rate ranges. Therefore, chipping size can be reduced largely by decreasing removal per grain.
Effect of grinding parameters on surface finish of ground ceramics
J.E. Mayer (2), G.P. Fang  
STC G,  44/1/1995,  P.279
Keywords: Grinding, Ceramics, Surface Finish
Abstract : Experimental research has been conducted into the effect of grinding parameters on surface finish 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 relationships between surface finish and the grinding parameters of grit sae, grit depth of cut, surface scallop height, chip cross-sectional area, and theoretical cutting edge spacing are explored. Two unique relationships appear to exist between surface finish and chip cross-sectional area; one below chip cross-sectional area of 0.1 pm' and another above this value. The relationship between surface finish and theoretical cutting edge spacing shows the best fit for all test data.
Basics of process parameter selection in grinding of advanced ceramics
G. Warnecke, U. Rosenberger   / J. Milberg (1)
STC G,  44/1/1995,  P.283
Keywords: Ceramic, Grinding
Abstract : The operational properties and the performance of components consisting of advanced ceramic materials, for example silicon carbide and silicon nitride, are mainly influenced by processing technology and process conditions. In grinding operations grain engagement and process kinematics determine the resulting surface topography as well as the degree of potential rim defects. The modelling of grain engagement and the computation of uncut chip thickness describe suitable ranges for process parameters resulting in minimized subsurface damages of the ceramic part. By means of single grain diamond scratch tests the limiting uncut chip thickness at the transition between plastic deformation of workpiece material and the occurrence of brittle microchippings during chip removal is evaluated. Based on theoretical models and experimental investigations a contribution to practical applications in grinding of advanced ceramics is explained.
Analysis of mirror surface generation of hard and brittle materials by ELID (Electrolytic In-Process Dressing) - Grinding with superfine grain metallic bond wheels
H. Ohmori, T. Nakagawa (1)  
STC G,  44/1/1995,  P.287
Keywords: Damage, Dressing, Grinding, Removal Mechanism
Abstract : Mirror surface grinding operators were conducted by using ultrafine grain metallic bond wheels with electrolytic in-process dressing (ELID) Workpieces of hard and brittle materials, such as monocrystalline silicon, glass, and ceramic, were ground. Wheel abrasive grains used mainly were diamond of several microns down to sub-microns Ground surface roughness versus grit size was shown. SEM and AFM were adapted to analyze ground mirror surface generation, and surface topographies due to grit size were compared. Subsurface damage was evaluated through X-ray, angle-polish and step-etching. High surface accuracy, good surface finish, and low subsurface damage were all successfully achieved. The advantage of a constant in-feed pressure in ultrafine grinding was shown, and Ra of several angstroms was achieved.
Porous fine CBN stones for high removal rate superfinishing
Y. Onchi, N. Ikawa (1), S. Shimada (2), N. Matsumori  
STC G,  44/1/1995,  P.291
Keywords: Superfinishing, Cubic Boron Nitride, Porosity
Abstract : For obtaining better finish comparative to that by But aluminum oxide stones, recommendation is made for the use of finer CBN stone. In order to prevent possible loading on the working surface of fine CBN stones, a porous structure is proposed The porous stone is composed of fine CBN grain and vitrified bond in which art dispersed intrinsic residual pores and extra pores the diameters of which are one to an order of magnitude as large as grain size for easier chip flow. By the use of appropriate stones under proper cutting condition, fine superfinishing with higher stock removal rate and much longer tool life are achieved than that by conventional aluminum oxide stones.
Investigation of surface integrity by molecular dynamics simulation
R. Rentsch, I. Inasaki (1)  
STC G,  44/1/1995,  P.295
Keywords: Abrasion, Surface, Simulation
Abstract : Difficulties in measurements at the abrasive/work contact when machining materials, as well as in determining the integrity of machined surfaces, have led to an increased attention in Molecular Dynamics (MD) simulation as it can provide a more detailed insight in the process and the machined surface. By means of MD simulation, the possibility ho investigate the influence of abrasive processes on the integrity of machined surfaces will be discussed. The surface integrity will be described in terms of dislocation building, surface roughness, residual stresses, and crack initiation in particular. For the first time, it was possible to simulate crack initiation in indention on brittle materials.
Characterization of dressing processes by determination of the collision number of the abrasive grits
E. Brinksmeier (2), M. Cinar  
STC G,  44/1/1995,  P.299
Keywords: Dressing, Grinding, Cubic Boron Nitride (CBN)
Abstract : A mathematical model is developed to determine his collision number between the diamond grits of a rotating dresser and his grits of a CBN grinding wheel. This model considers the kinematical influences of the dressing process and the specifications of both tools. A collision number i_d is defined which takes into account the specifications of the CBN wheel and the diamond dressing tool and also the overlap factor U_d and the speed ratio q_d during dressing. Comparisons between theoretical calculations and practical investigators show that the active surface topography of the grinding wheel after dressing strongly depends on his collision number i_d.
Appropriate conditioning strategies increase the performance capabilities of vitrified-bond CBN grinding wheels
F. Klocke, W. König (1)  
STC G,  44/1/1995,  P.305
Keywords: Cubic Boron Nitride (CBN), Dressing, Grinding
Abstract : A considerable improvement in the performance of grinding wheels can be achieved by means of ultra-hard abrasive materials, such as cubic boron nitride (CBN) A growing range of applications can be noted in particular for vitrified-bonded CBN grinding wheels An essential criterion for an efficient CBN grinding process is suitable conditioning of the grinding wheel. Investigations were carried out into various truing and dressing proves providing a broad range of variation for the preparation of vitrified-bonded grinding wheels. On the basis of there investigators, strategies and parameters for conditioning operations are discussed win the aim of establishing appropriate process contemptuous.
CBN grinding with small wheels
H.K. Tönshoff (1), H.G. Wobker, G. Brunner  
STC G,  44/1/1995,  P.311
Keywords: Cubic Boron Nitride (CBN), Residual Stresses, Temperatures
Abstract : Vitrified bonded CBN wheels have proved their benefits in industry mainly in internal grinding processes The present paper describes a strategy for an economical application of CBN in external grinding, with an adapted CBN technology employing small wheel diameters to reduce the initial costs. Compared to conventional grinding with an adapted CBN grinding strategy tool life, productivity, workpiece roughness and residual stress state of the workpiece can be improved significantly. However, even with CBN thermal damage of the workpiece surface can occur. In order to avoid thermal damage of the workpieces and to exploit the potential of CBN a temperature model to predict residual stresses of the workpiece surface based on the grinding parameters is developed.
Grinding assisted by Nd : YAG lasers
E. Westkämper (2)  
STC G,  44/1/1995,  P.317
Keywords: Grinding, Conditioning, Laser
Abstract : High-performance lasers can be actively used to assist grinding and conditioning (truing, dressing and cleaning) processes, and for an integrated heat treatment. The advantages of laser-assisted conditioning are the force-bee working principle and no necessity of expensive conditioning tools. In laser-assisted grinding, the workpiece area is heated directly before the grinding wheel is engaging, thus reducing the temperature gradient as well as surface layer damage. Moreover, the method permits high stock removal rates. This paper deals with the fundamentals of this method and presents a number of results from laser assisted conditioning of resin-bonded CBN grinding wheels as well as from laser-assisted machining of metal and ceramic components.
Model of gear grinding process
B.W. Kruszynski   / L. Nawara (1)
STC G,  44/1/1995,  P.321
Keywords: Grinding, Gear, Thermal
Abstract : The mathematical model of a generating gear grinding process is presented in the paper Detailed analysis of the creation of the tooth profile resulted in evaluation of the shape of a material layer being removed in a particular generating stroke of a grinding wheel and consequently in calculation of grinding forces, power density distribution on a wheel/workpiece interface and in calculation of temperature distribution in gear tooth during grinding This in turn may be utilised to predict such surface integrity parameters as residual stress, micro-hardness distribution, burns or cracks. Some experimental results, which confirm the model, are also presented in the paper.
Thermal behaviour of cutting grain in grinding
T. Ueda, M. Sato, T. Sugita, K. Nakayama (1)  
STC G,  44/1/1995,  P.325
Keywords: Grinding, Temperatures, Measurements
Abstract : Temperature at the interface between the cutting grain and a workpiece is measured using a two-color pyrometer with a fused fiber coupler. For the cutting grain, a conical tool of translucent alumina is used. The infrared rays radiated from the interface and transmitted through the conical tool are accepted by a fused fiber coupler and led to two infrared detectors of different spectral sensitivity. The temperature increases rapidly and reaches a saturated value after a short time (about 0.1 ms). The saturated temperature measured increases with the increase in the cutting speed up to the melting point of the work material.
Experimental investigation of heat transfer in grinding
W.B. Rowe (1), S.C.E. Black, B. Mills, H.S. Qi, M.N. Morgan  
STC G,  44/1/1995,  P.329
Keywords: Grinding, Temperature, Damage
Abstract : New findings are presented for temperatures, heat flux distribution and the implications for workpiece damage and partition ratio. Workpiece temperatures were measured using a 25 mm single pole thermocouple assembly. It was found that the critical temperature for the onset of temper colours for ferrous materials lies within the range 450 to 500 deg. C. Measured temperature distributions in the contact zone compared best with theory assuming a square law heat flux. The effective contact length for vitrified CBN and alumina wheels was confirmed to be greater than the geometric value. Substantially lower partition ratios were found with CBN compared to alumina.
Grinding fluid application system design
J.A. Webster, C.L. Cui, R.B. Mindek   / R.P. Lindsay (1)
STC G,  44/1/1995,  P.333
Keywords: Grinding, Fluid, Design
Abstract : Coolant application in grinding processes is becoming more important as stock removal rates are increased and higher quality is demanded. This study has analyzed the limitations of current application systems and used fluid mechanics to develop flow conditioners to compensate for bends in pipes. New nozzle designs are presented that give long coherent jets, up to 45 m/s, maximizing the application of fluid into the grinding zone. The influence of nozzle position, jet velocity, and distance from the grinding zone is presented. A 26.596 increase in wheel life as a result of coolant application optimization during grinding of an aerospace component is reported.
Semi-ductile grinding and polishing of ophtalmic aspherics and spherics
Z. Zhong, V.C. Venkatesh (1)  
STC G,  44/1/1995,  P.339
Keywords: Ductile-Grinding, Polishing, Brittle Materials
Abstract : Ductile grinding yields surfaces whose precision is far beyond that expected of ophthalmic requirements. This process requires machine tools and cutting tools that are manufactured to sub micron tolerances and which require clean rooms, thus making its cost prohibitive. While fracture mode grinding, followed by lapping and polishing have been successful, this paper presents results of semi-ductile grinding that is followed by reduced polishing time without an intervening lapping operation. Using conventional CNC machining centres and/or dedicated machines, silicon, germanium and glass were ground by metal bonded and/or diamond bonded diamond wheels followed by conventional polishing techniques.
Precision finishing
M.C. Shaw (1)  
STC G,  44/1/1995,  P.343
Keywords: Grinding, Cutting, Nanotechnology
Abstract : The ultraprecision diamond grinding (UPDG) of hard brittle materials such as glass involves two important characteristics: unusually high values of effective negative rake angle and high ratios of radial to tangential components of mean force per grit. Reasons are given why the mean normal force per grit is a useful criterion relative to subsurface damage. Also discussed is why the term ductile machining for the related process - single point diamond turning (SPDT) is misleading.

 STC M 

Kinematics, frictional characteristics and wear reduction by PVD coating on ball screw drives
D. Spath, J. Rosum, A. Haberkern   / H. Weule (1)
STC M,  44/1/1995,  P.349
Keywords: Coating, Kinematic, Tribology
Abstract : As the kinematic knowledge gained from roller bearings cannot be applied to the ball screw drive, a separate description of the velocities in the pitch points is required. This makes it possible to indicate the friction components (rolling, bore and sliding friction) and the resulting wear mechanisms. The specific measures for wear reduction are derived from these. It is experimentally proven how PAD coatings optimized in accordance with this approach improve the frictional and wearing characteristic. The use of PAD coated ball screw drives allows reduction of idle times in machine tools by increasing the rapid traverse speeds.
Effect of low friction guideways and leadscrew flexibility on dynamics of high speed feed machines
Y.C. Chen, J. Tlusty (1)  
STC M,  44/1/1995,  P.353
Keywords: Path Errors, Feedforward Control
Abstract : Rolling type as well as hydrostatic guideways generate very little damping in the direction of the feed motion. The ballscrew/nut flexibility driving a mass of a table, as a spring-mass system attached to the servodrive spoils both the transient response to the NC command and the response of the driven mass to the cutting force. The improvements obtainable by various measures including feedforward, accelerometric feedback and tuned damper are discussed.
Analytical prediction of stability lobes in milling
Y. Altintas (2), E. Budak  
STC M,  44/1/1995,  P.357
Keywords: Chatter, Stability, Milling
Abstract : A new method for the analytical prediction of stability lobes in milling is presented. The stability model requires transfer functions of the structure at the cutter - workpiece contact zone, static cutting force coefficients, radial immersion and the number of teeth on the cutter. Time varying dynamic cutting force coefficients are approximated by their Fourier series components, and the chatter free axial depth of cuts and spindle speeds are calculated directly from the proposed set of linear analytic expressions without any digital iteration. Analytically predicted stability lobes are compared with the lobes generated by time domain and other numerical methods available in the literature.
A fuzzy variable structure adaptive control design for robot manipulators
D.B. Zhao, J.Y. Zhu (1)  
STC M,  44/1/1995,  P.363
Keywords: Robotic Manipulators, Fuzzy Logic, Optimization
Abstract : The increasing demand on robotic system performance leads to the use of advanced control strategies. This paper proposes a method of nonlinear feedback control introducing fuzzy inference into variable structure adaptive control for the nonlinear robot manipulator systems. The fuzzy inference is introduced to treat the nonlinearities of the control systems. The fuzzy logic control approach enhances the proposed variable structure adaptive control since it gives robust property against system uncertainties and external disturbances, and also expert's experience can be added into the controller in parallel. The controller is an intelligent one. An automated design technique to numerically optimize membership functions for the fuzzy controller is discussed. In addition, the method is capable of handling the chattering problem inherent to variable structure control simply and effectively. A simulation study of a robot manipulator with three degrees of freedom is presented to demonstrate these features of the method.
Development of ultra-precision machining center with close-loop structure and its control
K. Sawada, Y. Takeuchi (2), T. Sata (1)  
STC M,  44/1/1995,  P.369
Keywords: Ultra-Precision, Milling Machine, Stiffness
Abstract : A high stiffness is required to reduce the relative displacement between workpiece and cutting tool due to the cutting force even for ultra-precision machine tools. Thus, a lathe-type ultra-precision milling machine was designed with a pseudo ball endmill as a cutting tool. The study deals with the further improvement of stiffness by upgrading the milling machine to that with a closed-loop structure. Thus, two constraint axes are employed to form the closed-loop structure, and are able to move in cooperation with X and Z-axis movements. The effect of the closed-loop structure is confirmed experimentally as well as with FEM analysis.
A strategy for the compensation of errors in five-axis machining
S.C. Veldhuis, M.A. Elbestawi (1)  
STC M,  44/1/1995,  P.373
Keywords: Machining, Thermal, Compensation
Abstract : This paper outlines a strategy for error compensation in five-axis machining. The strategy uses a neural network model for compensation of errors due to changes in temperature and axis motion. Long term errors due to wear will be addressed with an adaptive approach. A method based on the analysis of the neural network weights is used for selecting the most relevant thermocouple inputs. Preliminary results show the strategy to be capable of holding the error to within 0.020 mm in the Z direction and 0.002° in the q_x direction. Similar results are obtained during a cutting test.
Five-axis surface interpolators
Y. Koren (1), R.S. Lin  
STC M,  44/1/1995,  P.379
Keywords: Numerical Control, Interpolator, Machine Tools
Abstract : A new interpolator architecture for surface machining on five-axis CNC machines was developed and tested This interpolator can handle quid: and precise production of both convex surfaces by using endmills and ruled surfaces by using flank-mills The main ideas are (1) Decomposing the surface into curves, (2) continuously maintaining the cutter axis perpendicular to convex surfaces (end mills) or parallel to ruled surfaces (flank mills) by calculating corresponding axial reference positions at each sampling period of his interpolator This real-time approach produces smoother surfaces and requires substantially less machining time compared to conventional off-line approaches.
Toolholder spindle interfaces for CNC machine tools
J. Agapiou, E. Rivin (1), C. Xie  
STC M,  44/1/1995,  P.383
Keywords: High-Speed Machining, Interfaces, Tools
Abstract : The paper describes designs and tests of two novel tool holder/spin die interfaces. Interface WSU-1 provides improved axial and radial accuracy, higher stiffness, insensitivity to high rpm, and the potential for being used without keys, while being compatible with standard 7/24 spindles and toolholders. lnterface WSU-2 is an inexpensive modification of the standard 7/24 interface with improved axial accuracy and stiffness characteristics. Cutting tests have confirmed the advantages of these interfaces.
OPERA - A new approach to robot programming
M. Weck (1), R. Dammertz  
STC M,  44/1/1995,  P.389
Keywords: Manufacturing, Robotic, Programming
Abstract : This paper presents a new, graphical approach to the definition of complex robot program structures, based on a task description by means of flowcharts. Thus the PC-based OPERA system relieves the user as far as possible from learning a programming language and simplifies a better structuring of robot programs. Parameters for statements and procedure calls are defined within dialog boxes. As the program code is generated automatically, different robot languages are no problem for the user. Based on this approach OPERA offers various functions to add user defined procedure libraries as well as new robot control statements. New functions can be integrated like standard statements. They are graphically represented by user defined icons and even new dialog boxes can be included. Features for debugging and the generation of application specific user interfaces complete OPERA to a structure oriented programming tool, addressing the needs of end users as well as those of application specialists.
Intelligent integrated diagnostics : development of the diagnostics system for on-line quality control of powder injection molding
S.R.T. Kumara (2), J.W. Lee  
STC M,  44/1/1995,  P.393
Keywords: Powder Injection Molding, Fault Diagnosis, Causality Network
Abstract : In this research the authors propose an integrated intelligent diagnostics scheme for the on-line quality control of the Powder Injection Molding (PIM) process. In specific, this paper concentrates on the computational methodologies related to the process diagnostics A causality network model and its underlying mathematics to represent the domain and case specific diagnostic knowledge of PIM process are discussed. Alternatives of hypothetical explanations to the product defects am generated by network conversion technique and abductive reasoning. Diagnostic solutions ere generated by applying verification criteria for the hypotheses. The effectiveness of the proposed methodologies are verified by testing real-life problems.

 STC O 

A modelling and simulation architecture or virtual manufacturing systems
K. Iwata (1), M. Onosato, K. Teramoto, S. Osaki  
STC O,  44/1/1995,  P.399
Keywords: Manufacturing, Modelling, Simulation
Abstract : Virtual manufacturing systems are integrated computer models that represent the precise and whole structure of manufacturing systems and simulate their physical and logical behavior in operation Since each virtual manufacturing system is an aggregation of various computer hardware and software, it is necessary to develop a system architecture which defines functional components required for modelling and simulation, interfaces between components, virtual-real interactions, and system infrastructure This paper deals with a modelling and simulation architecture for virtual manufacturing systems for the practical development and describes a method of modelling and simulation for distributed simulation of virtual manufacturing systems.
A methodology for an integrated design and process planning based on a concurrent engineering reference model
W. Eversheim (1), H. Ozengeld, W. Bochtler, R. Graessler  
STC O,  44/1/1995,  P.403
Keywords: Concurrent, Engineering, Methodology
Abstract : Based on Concurrent Engineering approaches a reference model and a methodology have been developed which support the integration of design and process planning The reference model consists of four partial models These are the activity model, the information model, the object model as well as the model of integration methods. Using activity, information and object model, the methodology enables a concurrent processing of design and process planning activities considering different objects of a product. Furthermore, the methodology supple an early transmission of information to following activities and a feedback of information to previous activities within the process chain of design and process planning making use of the model of integration methods.
Order control by a hierarchical, self-organizing computer system
H. Bley, J. Jostock, K. Rech   / K.G. Günther (1)
STC O,  44/1/1995,  P.407
Keywords: Production, Logistics, Scheduling, CAPP
Abstract : Job processing on the typical shop floor is normally influenced by technical or organizational dependent disturbances. Due to growing efforts to meet the customers' demands with respect to short notice changes to orders (product variants and delivery dates), MRP-systems and subordinate shop floor control systems such as scheduling systems have to deal with these disturbances. This forms the basis for a new approach to order control systems implementing cascaded control loops starting with customers' orders and regarding the aspects of real-time rescheduling, process plan alternatives as well as simulating the impacts on future machining and delivery shop order sequences. Reactions to disturbances are offered by a knowledge-based module. This paper describes a concept to help solve the problems encountered by the subcontractor. This concept is based upon a hierarchically organized distributed computer network enabled to reorganize itself in case of a computer or interface failure.
An evaluation system of order acceptability under consideration of machine loading in die manufacturing
M.S. Lee, H.M. Rho (2), M.J. Kang  
STC O,  44/1/1995,  P.413
Keywords: Die, Order Evaluation, Machine Loading
Abstract : In die manufacturing factories, orders are often accepted without reasonable evaluation. This incurs difficulties to generate an appropriate production schedule. By exploring some characteristics of die manufacturing, this paper proposes heuristic method for quick order acceptance evaluation which considers of both real and potential loads at the order evaluation phase. This method is implemented into a quick order evaluation system as a part of the integrated production management system, and can perform the order evaluation quickly by comparing all the standard operation times for main parts of a die set with available capacity of machines.
Machining economics in FMS by a fuzzy approach
S. Noto la Diega (2), A. Passannanti, G. Perrone  
STC O,  44/1/1995,  P.417
Keywords: Cost Analysis, FMS, Fuzzy Optimization
Abstract : In a conventional manufacturing system, cutting parameters have to be fixed in order to pursue the economical and productive target related to each cutting operation. In a Flexible Manufacturing System (FMS), as a consequence of the unbalanced workload due to the mutual interaction among the shared resources, the optimization of each operation does not allow the optimum of the global production system to be reached. A fuzzy programming model is developed in this paper in order to select cutting speeds of the operations in the production plan as a satisfying compromise solution between single operation and the integrated system targets.
Application of control theory for production logistics - Results of a joint project
G. Pritschow (1), H.P. Wiendahl (1)  
STC O,  44/1/1995,  P.421
Keywords: Production Logistics, Control, Modelling
Abstract : The area of production logistics has become a key issue for the success of a company in increasingly dynamic and competitive markets. For a better reaction to short term market changes and disturbances of the production process a transition from a static to a dynamic view, from an open to a closed-loop controlled system is necessary. Control theory based models have been developed allowing the prediction of control parameters and the logistic behaviour of closed control loops in quality and quantity. Studies of the dynamic properties of closed control loops reveal potentials for a better compliance with the logistic objectives.
Modelling and analysis of non-linear dynamics in autonomous heterarchical manufacturing systems control
V.V. Prabhu, N.A. Duffie (2)  
STC O,  44/1/1995,  P.425
Keywords: Manufacturing, System, Control
Abstract : Heterarchical architectures characterized by fully distributed control and cooperation among loosely-coupled autonomous entities have been proposed for controlling automated manufacturing systems. A non-linear, control-theoretic analytical model is developed in this paper to represent the dynamical behavior of closed-loop distributed controllers in autonomous part-driven heterarchical systems The model and the control law introduced for adjusting arrival times of parts to be processed allows the dynamics of these highly distributed, highly non-linear control systems to be analyzed Analytical and numerical results are used to validated the model and illustrate robustness to uncertainties such as new part arrivals and machine failures of the fully distributed, heterarchical system control.
The integration of process planning and shop floor scheduling in small batch part manufacturing
W.H.M. Zijm   / H.J.J. Kals (1)
STC O,  44/1/1995,  P.429
Keywords: Scheduling, Process Planning, Critical Path Method
Abstract : In this paper we explore possibilities to cut manufacturing leadtimes and to improve delivery performance in a small batch part manufacturing shop by integrating prowls planning and shop floor scheduling Using a set of initial process plans (one for each order in the shop), we exploit a resource decomposition procedure to determine schedules to determine schedules which minimize the maximum lateness, given these process plans. If the resulting schedule is still unsatisfactory, a critical path analysis is performed to select jobs as candidates for alternative process plans. In this way, an excellent due date performance can be achieved, with a minimum of process planning and scheduling effort.
Multi objective process planning in environmentallyconscious manufacturing : a feature based approach
P. Sheng, M. Srinivasan   / S. Kobayashi (1)
STC O,  44/1/1995,  P.433
Keywords: Machining, Environment
Abstract : Environmental factors have become important in manufacturing planning due to governmental regulations and a growing preference for "green" products. However, planning decisions must also consider traditional dimensions such as production rate and quality. Major issues for environmentally-conscious planning are (1) comparative assessment of waste stream and (2) computational complexity of evaluating multiple processing alternatives. Environmental impact of dissimilar waste streams is analyzed through a scoring system which evaluates factors such as toxicity, carcenogenesis, irritation, flammability, and reactivity. Complexity of processing alternatives is reduced through a feature-based approach, where the component environmental impact is decomposed into "micro" analysis of individual features and "macro" analysis of feature interactions.
Autonomous process planning with real-time machining forproductive sculptured surface manufacturing based on automatic recognition of geometric features
K. Yamazaki (2), Y. Kawahara, J.C. Jeng, H. Aoyama  
STC O,  44/1/1995,  P.439
Keywords: Sculpture Surface Manufacturing, Process Planning
Abstract : The paper deals with a study on technologies to enhance the manufacturing productivity of a product consisting of sculptured surfaces. A process planning system coupled with real time machining is proposed such that the productive machining plan and tool motion can automatically be generated once available resources and machining know-how are given for the metal cutting-EDM mixed environment. The system proposed consists of geometry feature recognition, cutting mode and tool selection, real time tool path generation with adaptive feedrate generation using concurrent real time machining simulation. The system was prototyped to verify the feasibility. Successful results were obtained.
Determination of the optimum tool set for a given batch of turned components
J.H. Zhang, S. Hinduja (2)  
STC O,  44/1/1995,  P.445
Keywords: Optimum, Tool, Batch, Balancing
Abstract : This paper describes a procedure to determine the optimum tool set for a batch of turned components, the optimisation criterion being either the minimum machining cost or minimum number of machine stoppages or a combination of both. A too-operation-cost table is constructed wherein the costs of machining an operation with individual tools are stored and the optimum tool set is obtained by searching this table exhaustively The wear rate of each tool is adjusted so that it machines an integral number of components, to reduce the machine stoppages, tool wear rates of the leading and shadowing tools are further adjusted so that tool changes are synchronised The factors considered in the optimisation include the number of turret positions, batch size and performance of individual and sister tools. To demonstrate the system, tool sets have been determined for a turned component for different optimisation criteria.
Future direct manufacturing of metal parts with free form fabrication
L.A. Killander, G. Sohlenius (1)  
STC O,  44/1/1995,  P.451
Keywords: Laser Sintering, Free Form Fabrication, TIPS
Abstract : In this paper manufacturing of metal parts with Free Foam Fabrication FFF is discussed. Thoughts and ideas has been inspired by the Theory of Inventive Problem Solving TIPS. Principles and effects based on work by Altshuller has been combined with knowledge on FFF. The time frame has been limited to what is likely to be achieved within the next two years Some promising ideas are the introduction of vibration and the use of multi phase materials.

 STC P 

Atomic-scale precision motion control stage (The Angstrom stage)
M. Holmes, D. Trumper, R. Hocken (1)  
STC P,  44/1/1995,  P.455
Keywords: Precision Motion Control
Abstract : This paper describes a magnetically-suspended six-degree-of-freedom precision motion control stage with sub-nanometer positioning stability inside a 100 mm cube of travel. This stage utilizes multiple electromagnetic actuators and capacitance probes to provide control forces and position feedback respectively. The suspended platen (3 kg mass) is floated in oil to enhance the performance of the magnetic bearings. The stage has been designed for use as a sample positioning stage for scanning-tunneling microscopy. We present images obtained by scanning-tunneling microscopy which show that the positioning noise of the stage is below 0.2 nm peak-to-peak over 5 seconds. These data demonstrate the utility of this stage as a new concept for precision motion control.
A 3D probe for measuring small blind holes
G.X. Zhang (1), S.M. Yang  
STC P,  44/1/1995,  P.461
Keywords: Measurements, Probe, Compensation
Abstract : A 3-D probe for measuring the diameter and form errors at any particular section for small blind holes or slots with diameter or width down to 0.2 mm and depth to diameter ratio up to 20 was developed. Since optical methods are difficult to use for measuring the diameter of blind hole at any cross section, a method with mechanical stylus was used. The stylus is treated as an elastic element and a theory of elastic transmission was developed. The stylus can be introduced to small holes automatically and the deflection of the measuring stylus is compensated. Experiments show that the accuracy is better than l mm.
Development of high-speed and high-accuracy straightness measurement of a granite base of a CMM
Y. Tani, K. Katsuki, H. Sato (1), Y. Kamimura  
STC P,  44/1/1995,  P.465
Keywords: CMM, Optical Measurement, Straightness
Abstract : The flatness of a granite base affects the volumetric accuracy of a probe in a CMM. Therefore a new optical straightness measurement with high speed and high accuracy is proposed in thus paper. High speed was attained by gliding the measurement head over the granite surface through the action of an aerostatic bearing pad. High accuracy was obtained by measuring the position of a laser beam on photodetectors. The straightness was estimated in terms of the vertical displacement and the integrated inclination of the slider, and the latter coincided well with the value measured using an electric level.
Assessment of dynamic errors of CMMs for fast probing
W.G. Weekers, P.H.J. Schellekens (2)  
STC P,  44/1/1995,  P.469
Keywords: CMMs, Dynamic, Error
Abstract : Due to the demand for shorter cycle times of measurement tasks, fast probing at CMMs becomes more important and the influence of dynamic errors of CMMs will increase. This paper presents an assessment of dynamic errors due to carriage motion. Based on the analysis of the dynamic errors of a specific CMM a practical approach was chosen. In this approach the major joint defections due to accelerations are measured with position sensors. Possibilities for estimating other joint defections by analytical modelling of CMM components are discussed. Using a kinematic model of a CMM, the influences of the measured and estimated joint defections on the probe position are calculated. A description of a measurement setup for one axis of a CMM is given to illustrate the approach. The results show that measurement and estimation for at least pad of the dynamic errors is possible.
Effects of arbitrary coefficients of CMM error maps on probe qualification
A. Balsamo (2)  
STC P,  44/1/1995,  P.475
Keywords: CMM, Multi-Stylus
Abstract : For a consistent definition of the geometrical error functions of a CMM some of their low-order parameters must be set arbitrarily. When a multiple stylus configuration is not used for the measurement of the error parameters, the available information is not complete and compensation errors may be generated by a subsequent use of multiple styli. However, these errors can be avoided by taking some precautions in the probe qualification. The theoretical as well as experimental importance of this is pointed out, and the consequences in the probe qualification and in the simulation of CMMs (virtual CMMs) are discussed.
Results of international comparison of ball plate measurements in CIRP and WECC
H. Kunzmann (1), E. Trapet, F. Wäldele  
STC P,  44/1/1995,  P.479
Keywords: Coordinate Measuring Machines (CMM), Calibration, Inspection
Abstract : A comparison was conducted for the calibration of commercially available ball plates. Twenty six metrology laboratories from fifteen countries participated with a total of thirty eight individual measurements. The method of measurement was strictly prescribed and the results were evaluated by the PTB as the reference laboratory in comparison to the reference values. The measurements showed a high degree of conformity of about 2*10^-6 in over 60%37; of all cases. In 30%37; evident problems which can easily be overcome were the reasons for less good results. The ball plates showed sufficient dimensional stability overtime of about l*10^-6 per year (m the worst case) Findings resulting from the inter-comparison suggest ways to improve the stability of ball plates by better design details.
On-line failure detection in face milling using discrete wavelet transform
N. Kasashima, K. Mori, G. Herrera Ruiz   / N. Taniguchi (1)
STC P,  44/1/1995,  P.483
Keywords: Monitoring, Milling, Diagnostic Routine
Abstract : This paper describes an application of the Discrete Wavelet Transform (DWT) to detecting tool failures in face milling operations. The wavelet transform uses an analyzing wavelet function which is localized in both frequency and time to detect subtle time localized small changes in the input signals. In this paper, the DWT is used to detect tool failures such as small chipping and breakage of an insert tip including eccentricity of the tool rotation center. The results indicate that the DWT can extract tool failures with much greater sensitivity than the FIT even when the amount of chipping is very small. In addition, the DWT enables the analyst to determine which insert tip failed, since it yields time localized signal information. On-line diagnosis of tool failures are demonstrated in both simulated and actual cutting force signals by using simple pattern recognition technique.
Nanometer measurement of silicon wafer srface texture based on Fraunhofer diffraction pattern
T. Miyoshi, Y. Takaya, K. Saito (2)  
STC P,  44/1/1995,  P.489
Keywords: Surface Texture, Ultra-Precision, Optical Measurement
Abstract : A new optical measuring method which can be applied to in-process measurement of surface defects as well as microroughness of ultra-fine finished surfaces with an accuracy of nanometer order is presented in this paper. The principle of our method is based on the Fraunhofer diffraction theory taking account of Gaussian laser beam propagation. The feasibility of the proposed optical method is verified by measurements of the ultra-fine polished silicon wafer surfaces. Consequently, the Fraunhofer diffraction method makes it possible to not only measure microroughness of less than 1 nm Rrms, but also detect distinctively micro-scratches, pinholes and particles.
Generalized aspects of multiple-wave length techniques in optical metrology
T. Pfeifer (2), R. Tutsch, J. Evertz, G. Weres  
STC P,  44/1/1995,  P.493
Keywords: Metrology, Optical Measuring Instruments, Dimensional Measurement
Abstract : Various optical measurement techniques are based on mathematical equations that have a common formal structure. A characteristic feature of a so-called fundamental interferometric equation of this nature is the limitation imposed on the unambiguous measurement range by the periodicity of the trigonometric functions. Back at the end of the 19th century, Michelson developed the concept of multiple-wavelength interferometry in an effort to overcome this problem. Nowadays, the availability of powerful microcomputers permits generalized multiple wavelength techniques to be used in a wide variety of fields of application including optical shop testing, fringe projection profilometry and TV holography. The basic concept and new developments are discussed in this paper, giving examples of current applications.
The shadow Moiré method applied to 3D model copying
A. Del Taglia, A. Paolucci   / M. Santochi (1)
STC P,  44/1/1995,  P.497
Keywords: Dimensional Measurement, Image Processing, Moiré Pattern
Abstract : The paper-deals with the problem of testing, measuring, or copying JD shapes from a physical object using a digital elaboration based on a telecamera image. Utilising the shadow moire method, light and dark interference fringes are created on the image of the object end each fringe relates to a well defined depth; this information, together with the image plane measurement, fan be used to obtain a complete 3D shape model reconstruction Descriptions of the principal problems encountered and the solutions adopted are discussed. Problems include a need to improve poor resolution and precision resulting from off-the-shell instrumentation, as well as difficulties related to the automatic hinge analyses and to the creation of a mathematical model to be imported in a CAD system However, considering that only commercially available and low cost instrumentation has been used, the method, though not feasible for all applications, produces a satisfactory overall performance
Metrological limitations of optical probing techniques for dimensional measurements
L. De Chiffre (2), H.N. Hansen  
STC P,  44/1/1995,  P.501
Keywords: Dimensional Metrology, Optical Probe, Accuracy
Abstract : Based on experimental results from a series of investigations, this paper deals with the metrological limitations of optical probing techniques in the field of dimensional metrology. The optical probing systems considered herein comprise an optical coordinate measuring machine, an experimental optical roundness tester and an optical measuring station for dimensions which is under development for integration in a production line. In all these cases, a single measurement micrometer accuracy is required but hard to achieve. The influences from sensor, optical system, illumination, object, background, and mechanical system, are evaluated. Guidelines are suggested which can be used to optimize the accuracy in measuring situations.

 STC S 

Application of the filter with dynamically controlled transmission band in surface texture analysis
T. Klimczak (2), Z. Handzel-Powierza  
STC S,  44/1/1995,  P.505
Keywords: Surface, Roughness, Filter
Abstract : In some issues of engineering surfaces characterization it is necessary to separate topographical features of surface. If we are dealing with multi-scale features of surface topography conventional surface filtering techniques are limited. The paper presents method of controlling of filter transmission band over the data space. The method used originally in image processing was adopted for identification and localization of topographical features on engineering surfaces. This method of filtering allows for proper separation of features of different scales which, for its different functional meaning, should be analyzed separately. The method applied to three-dimensional topographical data demonstrates its usefulness in preparing data for pattern analysis of surface features such as grooves, contact spots, lay, defects etc.
Analysis of machined surfaces through diffraction patterns and neural networks
P.M. Lonardo (1), A.A. Bruzzone, A.M. Lonardo  
STC S,  44/1/1995,  P.509
Keywords: Surface, Diffraction, Neural Network
Abstract : The analysis of diffraction patterns obtained from machined surfaces can be used to characterise the microgeometry and, consequently, the production process. Unfortunately, the analysis applied to real surfaces is rather complex. In this paper a new approach based on the technique of the neural networks is proposed to recognise turned surfaces. The diffraction images are acquired and the distributions of the light intensity are used as inputs to the networks. The ability of supervised networks of classifying the surfaces according to the received training is assessed With unsupervised networks a classification of the surfaces in quality levels is performed.
Assessment of subsurface damage in ultraprecision machined CdS by ion channeling
D.A. Lucca, R.L. Rhorer,C. Maggiore, Y.W. Seo   / R.R. Donaldson (1)
STC S,  44/1/1995,  P.513
Keywords: Cutting, Surfaces, Ultra-Precision Machining
Abstract : The depth of the subsurface damaged layer in ultraprecision machined CdS was examined by studying the interaction of energetic ions with the workpiece surface Single crystal (0001) oriented CdS was diamond turned at depths of cut of 01 and 1 25 mm, and subsurface lattice disorder was examined for regions cut parallel to, and 30 degrees off, a preferred cleavage plane. The energy spectrum of 2 MeV ^4 He^+ ions backscattered from the crystal surface was used to obtain a depth of the disorder Results were compared to there obtained for chemo-mechanically and hydroplane polished surfaces.
Roughness parameters of surfaces by atomic force microscopy
K. Carneiro, C.P. Jensen, J.F. Jorgensen, J. Garnoes   / P.A. McKeown (1)
STC S,  44/1/1995,  P.517
Keywords: 3D Surface Topography, Roughness, Atomic Force Microscopy
Abstract : We present a standardized measurement report for surfaces investigated by scanning probe microscopy (SPM), which include twenty three-dimensional roughness parameters to characterize the surface topography. The examples are some polished copper samples and the scan size is 5 um x 5 mm. Some of the parameters are generalizations of two-dimensional standards, and some are three-dimensional parameters normally used at larger scan sizes (mm x mm). Furthermore, there are some newly developed parameters extracted from Fourier analysis that reflect the directionality of surface texture. The parameters are discussed and it is shown that not all parameters are giving meaningfully information on um-range scans.
Brittle-Ductile transition phenomena in microindention and micromachining
S. Shimada (2), T. Inamura, N. Takezawa, H. Ohmori, T. Sata (1), N. Ikawa (1)  
STC S,  44/1/1995,  P.523
Keywords: Micro Machining, Ductile Transition, Brittle Material
Abstract : A generalized hypothesis for the brittle to ductile transition in micromachining and microindentation of brittle materials is proposed By the hypothesis, complicated transition phenomena observed in practical machining processes are well explained Experimental results on microturning, ELID grinding of monocrystalline Si and LiNb03 support the applicability of the hypothesis Microindentation testing is shown to evaluate the intrinsic ductility and critical scale of machining for ductile mode machining To analyze the machining prowssin extremely small scale, molecular dynamics computer simulations of microindentation and cutting are made on a defect-free surface These results suggest that any material, in spite of their ductility, can be machined in ductile mode under the sufficiently small scale of machining.