Assembly of large products
G. Boothroyd (1), M. Fairfield  
STC A,  40/1/1991,  P.1
Keywords: Assembly, Design, Acquisition, Handling
Abstract : The need for a method of estimating assembly times for large products during the product design phase is discussed. An approach to the development of a database of part acquisition and handling times is described and some preliminary results are presented. Comments and conclusions are made regarding the feasibility of the proposed approach.
Pre-fabricated carbide tips handlin
D. Milutinovic, M. Pilipovic   / M. Kalajdzic (1)
STC A,  40/1/1991,  P.5
Keywords: Handling, Carbide Inserts, Manipulation System
Abstract : The solving of the problem of automated handling of pre-fabricated carbide tips aimed at improving and maintaining the quality, productivity and humanization of work is a very complex engineering task. The complexity of the problem of automated handling primarily relates to the possibility of easy damageability of pre-fabricated tips very limited space and short time cycle for their taking out of the press. The paper in detail analyses this problem and presents a developed concept of a manipulation modular-based system. In comparison with the existing systems the basic advantage was achieved i.e. the flexibility and sophisticated control. This developed system solves the problem of the handling of pre-fabricated tips in small companies.
Kinematic calibration of SCARA robot with condition number and error Map method
S. Toyama, S. Hatae, T. Haga   / K. Kinoshita (1)
STC A,  40/1/1991,  P.9
Keywords: Assembly Machines, Calibration, Error Analysis
Abstract : This paper presents a new kinematic calibration method based on condition number and an error map method for SCARA robots. The geometric parameters can be identified more precisely by measuring the positions of a hand with minimum condition number configuration. Furthermore. the error map method improves the accuracy of geometric parameters. The experimental results demonstrate that this calibration method made the maximum absolute positioning error of a typical SCARA.DD robot less than 0.25 mm all over the working area, while the maximum error was 2.20 mm in the case of the conventional method.
Choice of optimal configurations for flexible (readjustible) assembly lines by purposeful search
A.I. Dashchenko   / T.N. Loladze (1)
STC A,  40/1/1991,  P.13
Keywords: Assembly, CAD
Abstract : A comprehensive CAD system is outlined for grouped assembly processes in the automobile industry. The ideology is described more thoroughly of developing a configuration choosing module. Examples are reported of designing assembly lines for car electric systems.
Robotized assembly of modular fixtures
F. Giusti (1), M. Santochi (2), G. Dini  
STC A,  40/1/1991,  P.17
Keywords: Assembly, Planning, Fixtures
Abstract : A prototype plant for the robotized assembly of modular fixtures for NC machining centers is described. After presenting a brief summary of the present tendencies relative to the design, preparation and management of the fixtures, the plant and its components are described in their general structure, posing particular focus on the geometric and functional features of the modular elements, designed in order to facilitate the automatic operations of manipulation and assembly. The plant is controlled by a software structured for design of fixture configuration, planning of the assembly sequence and off-line programming of the robot. Results obtained in assembly tests are also discussed, and emphasis is placed on the more critical aspects linked to the automation of this important operation. In conclusion, the possible applications of the automatic assembly of fixtures for FMS plants are proposed.
SMD reflow soldering : a thermal process model
P.P. Conway, A.O. Orgunjimi, P.M. Sargent, A.C.T. Tang, D.C. Walley, D.J. Williams   / A.W.J. Chisholm (1)
STC A,  40/1/1991,  P.21
Keywords: Assembly, Electronics, Soldering
Abstract : This paper presents a number of numerical process models of the infra-red reflow soldering process, the major joining process for surface mount electronic assemblies. The aim of this work is to investigate the key process and design variables and their effect on joint quality in the final assembly. The paper includes models of a bare printed circuit board and "J and Gull-Win," leaded components on a printed circuit board all passing through an infra red oven. The process models are based on the IDEAS modeling suite and TMG thermal solver and are likely to find application process design.


Computerized end-milling force predictions with cutting models allowing for eccentricity and cutter deflections
E.J.A. Armarego (1), N.P. Deshpande  
STC C,  40/1/1991,  P.25
Keywords: End-Milling, Eccentricity, Cutting Forces, Milling, CAD/CAM
Abstract : In this paper further developments of computer based mechanics of cutting models and software modules for the prediction of the average and fluctuating force components and torque in End milling are considered and assessed by numerical simulation and experimental testing. Three modes are considered namely, the 'ideal' model for rigid cutters with no eccentricity, the rigid cutter 'eccentricity' model and a more comprehensive 'deflection' modes allowing for both eccentricity and cutter deflections. It is shown that the 'idea:.' model provides useful qualitative tends for the average forces and torques which /are /similar for a:1 three models but yields poor qualitative force fluctuation predictions. The 'eccentricity' model yields good predictions of the average forces and torque while the fluctuation predictions are also good out deteriorate for unfavourable cutter deflection while the 'deflection' model provides the best predictions and correlation with the 350 experimental test results but at the expense of excessive computer processing time. The practical Implication of these models and the importance of both eccentricity/ /and cone- deflection en the force fluctuations are discussed.
General end-milling force algorithms for CAD systems
Y. Altintas, A. Spence   / J. Tlusty (1)
STC C,  40/1/1991,  P.31
Keywords: Milling, Solid Modelling, Cutting Forces
Abstract : This paper presents an efficient milling mechanics simulation system for use with solid modeler based tool path generation algorithms. The technique provides computationally efficient cutting force predictions for end milling of general part shapes. First, the part is described using the Constructive Solid Geometry representation scheme. Along the cutter path the tool-workpiece interaction is represented using immersion arc segments obtained by intersecting the cutter with each part feature. Next, a cutting mechanics model is used to predict the instantaneous, average and peak forces, and maximum cutter deflections left on the finished part surface. By separating the cutter constants from the part geometry, the model allows automatic feed rate scheduling to satisfy end milling constraints. Verification of the method by both simulation and experiment is included.
A tool temperature - tool-life relationship covering a wide range of cutting data
B. Colding (1)  
STC C,  40/1/1991,  P.35
Keywords: Cutting, Temperature, Tool-life
Abstract : The paper shows that maximum tool-life, or minimum temperature, for any given metal removal rate of a cutting tool or grinding wheel is governed by the principle of minimum thermal energy, resulting in one single relationship between metal removal rate per unit cutting edge length and tool-life, or temperature, for each tool - work combination. A tool temperature relationship, of the same form as the author's tool-life relationship, is derived, the constants of which can be calculated from temperature tests and two tool-life calibration tests.
On-line estimation of groove wear in the minor cutting edge for finish-machining
Y. Yao, X.D. Fang, G. Arndt (1)  
STC C,  40/1/1991,  P.41
Keywords: Tool Wear, Cutting Edges, Statistical Analysis
Abstract : The paper investigates the effective detection and estimation of groove wear at the minor cutting edge, which has a vital influence on surface quality in finish-machining. During bar-turning experiments with different cutting conditions, a miniature 3-D accelerometer, mounted in close vicinity to the tool tip, was used to measure the multivariate vibration signal produced by the turning process. The stochastic signal was modeled as autoregressive vector difference equations, and multiple dispersion analysis was used to quantify the complex interactions among various variables. It was found that the characteristic ingredient of vibration in the thrust direction, complemented by that in the main cutting direction, signifies effectively the critical point at which grooves are being "chiseled out", surface roughness is deteriorating rapidly, and subsequently the finishing-tool needs to be replaced. The results are interpreted on a physically sound basis. The results also show that the algorithm developed is a feasible approach to on-line monitoring of minor cutting edge groove wear in finish-machining.
Tool life scatter when milling with TIN coated HISS indexible inserts
G. Byrne, B. Bienia   / G. Duelen (1)
STC C,  40/1/1991,  P.45
Keywords: Cutting, Milling, Tool Life Scatter, Coated Cutting Tools
Abstract : Results of experimental investigations into the tool life scatter which occurs in face milling with titanium nitride coated high speed steel indexible inserts are presented and discussed The tools investigated were coated under closely controlled conditions using Physical Vapour Deposition (PVD) technology. The scatter between the four corners of a single indexible insert was found to be very significant. Many important questions in relation to substrate preparation for coating, coating process conditions and method of cutting tool implementation in the machining process arise as a result of the analysis undertaken. It is shown that the orientation, location and method of fixing of the cutting tools in the coating chamber effect the tool life scatter.
Cutting performance and wear characteristics of an alumina-zirconia ceramic tool in high speed face milling
N. Narutaki, Y. Yamane, K. Hayashi   / T. Hoshi (1)
STC C,  40/1/1991,  P.49
Keywords: Cutting, Ceramic Tools
Abstract : High speed face milling for plain carbon steel S45C was carried out with ceramic tools. Pure alumina, TIC added alumina, and zirconia toughened alumina ceramic tools were mainly used. Among the tested ceramic tools, the zirconia toughened alumina ceramic tool sowed the largest crater wear resistance in high speed face milling. However, in turning the same steel, the crater wear resistance of the ceramic tool was almost the same degree as compared to the other ceramic tools. The superior wear resistance of the zirconia toughened alumina ceramic tool is based on its stability for the reaction to Fe0 at high temperature.
Investigation of face turning on NC lathes
E. Kuljanic (1)  
STC C,  40/1/1991,  P.53
Keywords: Cutting, Face Turning, CNC lathes, Productivity Increase, Tool Life, Surface Roughness
Abstract : This paper presents the results of a research on face turning on CNC lathes at constant cutting speed and at constant spindle revolutions. In both cases the surface roughness is examined by using different machine tools, with different tools, and at different cutting conditions, a comparison is made of cutting time in face turning at constant cutting speed and at constant spindle revolution. Furthermore, this paper deals with a comparison of tool wear, tool life, the area of machined surface and the gain for obtained at constant cutting speed and at constant spindle revolutions. The cutting time is shorter by approximately 45%37; when face turning os done at constant cutting speed.
Effect of micro-cracks in CVD coated layer on transverse rupture strength and chip resistance
S. Katayama, M. Hasimura, T. Tanaka, H. Imamura   / K. Uehara (1)
STC C,  40/1/1991,  P.57
Keywords: Cutting, Coated Carbides, Residual Stresses
Abstract : Micro-cracks were artificially induced in the CVD coated layers on a cemented carbide tool by a mechanical method. The cracks have beneficial effects on the transverse rupture strength and the chipping resistance during interrupted cutting. With decreasing mean value of distances between cracks from 400 to 20 mm, the transverse rupture strength increased from 1.2 to 2.05 GPa and the chipping resistance about doubled. It seems that/ /the improvements are closely related to the relief of residual tensile stress in the coatings.
A. J-integral approach to material removal mechanisms in microcutting of ceramics
K. Ueda, T. Surgita, H. Hiraga   / K. Iwata (1)
STC C,  40/1/1991,  P.61
Keywords: Cutting, Ceramics, Brittle-Ductile Transition
Abstract : An approach to analyzing material removal mechanisms in micro-cutting of ceramics is described. The approach is based of the J-integral method capable of elastic-plastic fracture mechanisms. The J-integral value around a track ahead of the cutting edge is determined using the finite element method. Both the brittle and ductile mode material removal mechanisms are analyzed by considering crack propagation and plastic deformation behavior. The brittle-ductile transition is elucidated for the selected ceramics materials and the applicability of the ductile mode removal ids also discussed in terms of the material properties and cutting condition.
Bluntness of the tool and process forces in high-precision cutting
D.A. Taminiau, J.H. Dautzenberg (2)  
STC C,  40/1/1991,  P.65
Keywords: Cutting, Cutting Forces, Tool Wear
Abstract : The influence of bluntness of the cutting tool edge is considerable when making smaller cuts, particularly in high precision cutting. In this paper its influence on the process forces is investigated. It has been approximated by a rounded tool edge. In that case, Abdelmoneim's model for determining the tool forces when cutting with a rounded tool edge, is applicable. Rough cutting experiments have been carried out using tools ground with large edge radii. Force measurements have been compared with the theoretical results from Abdelmoneim's model. In addition the model has also been used for high-precision cutting experiments.
Energy dissipation in the ultra-precision machining of copper
D.A. Lucca, R.L. Rhorer, R. Komanduri (1)  
STC C,  40/1/1991,  P.69
Keywords: Cutting, Ultra-Precision Machining, Specific Energy
Abstract : An experimental study of the forces involved in the orthogonal single point diamond machining of oxygen free high conductivity (OFHC) copper and fine grain copper was performed. Depths of cut ranged from 15 mm down to 0.025 mm and cutting speeds ranged from 6 m/min to 107.7 m/min. cutting and thrust forces were measured. The total specific energy is seen to significantly increase at small depths of cut, consistent with observations reported in the literature. An overall energy balance indicates that at depths of cut below several micrometers shearing in the shear zone is unable to account for the observed energies. Flank face rubbing due to workpiece material elastic recovery and plowing due to the edge radius of the tool may take on increased roles as mechanisms of mechanical energy dissipation in micro-machining.
Chip control in cut-off tools
J. Rotberg, A. Ber (1), R. Wertheim (1)  
STC C,  40/1/1991,  P.73
Keywords: Cutting, Grooving, Chip Formation
Abstract : This paper deals with the family of "Cut-Off" tools. In said family of tools, the role of chip control, i.e. chip formation and chip flow, is quite essential, since it should enable the extraction of the generated chip but of the machined slot without causing any damage to the workpiece. It is important not only to have chip curling, but also material flow toward center of rake face in order to narrow the chip in comparison to the slot. Chip formation characteristics, chip cross-section and chip curling were investigated experimentally while influencing parameters such as insert geometry, arid cutting conditions were studied. The study of the chip formation at the cross-section plane (perpendicular to the chip flow direction) was specially emphasized. The results lead to the understanding and definition of tool performance in terms of insert geometry, cutting conditions and chip form.
Formation of flank build-up in cutting magnesium alloys
N. Tomac, K. Tonnessen   / F. O. Rasch (1)
STC C,  40/1/1991,  P.79
Keywords: Cutting, Magnesium, Build-up
Abstract : Flank build-up on HM cutting edges at speeds in excess of approximately 600 m/min may constitute a problem when running magnesium alloys. SEM analyses of workpiece materials, tool inserts with flank build-up and flank build-up itself indicate that manganese compounds play an important role in forming very card particles and through a high degree of attraction to the tool material. Three Mg-Al-Zn alloys with different manganese content were turned under different cutting conditions in order to determine the tool-workpiece interaction at different cutting speeds. All three alloys gave the same type of flank build-up, the critical cutting speed which expresses the tendency to form flank built-up, was however different for the three alloys.
Burrless drilling by means of ultrasonic vibration
H. Takeyama (1), S.Kato  
STC C,  40/1/1991,  P.83
Keywords: Ultrasonic Drilling, Burr, Material Deterioration in Drilling, Burrless Drilling, Radial Peripheral Lip Drill
Abstract : In order to achieve edge integrity in view of burr, flaking, chipping, material deterioration, etc, in drilling operations, ultrasonic vibration has been applied in the direction of drill feed. The multiplying effect of ultrasonic vibration and newly developed radial peripheral lip drill has been experimentally demonstrated to be extremely effective for preventing burr and material deterioration et the exit of drilled hole of aluminum and glassfiber reinforced plastics.
Wälzfräsen von Kupplungs - Planverzahnungen - Analyse der Verfahrenskinematk durch Simulation
L. Cronjäger (1), A. Steinwachs  
STC C,  40/1/1991,  P.87
Keywords: Hobbing, Crown Gears, Tooth Clutches
Abstract : The machining of crown gear rims, applied in tooth clutches for torque transmission, usually is done by milling using the indexing method, involving long machining times and the risk of edge contact. The paper deals with a new hobbing method, that enables an economical manufacture of spirally curved crown gears with conventional spur gear generating machines. In order to optimize the contact characteristic and the tool design, the kinematics of the procedure have been analyzed by computer simulation, so that the shape of the generated teeth is calculable just as well as the chip width and the working clearance angles.
The workpiece material-laser interaction and the laser-assisted machining
G. Marot, L.J. Fan, A. Tarrats, p. Cohen, J.P. Longuemard   / A. Moisan (1)
STC C,  40/1/1991,  P.91
Keywords: Laser, Laser-assisted Machining, Roughness, Laser-Material Interaction, Diffusion Energy
Abstract : During the laser-assisted machining, only a small part of the laser beam is absorbed by the workpiece. So it seems useful to study the diffused beam angular distribution, and to find out the relation between this distribution and the surface finish, in certain conditions is impossible to get a better efficiency for the laser-material interaction. This paper describes an experimental study of this kind, and some conclusions which can be tough from a practical point of view.
Operation planning based on cutting process models
M.D. Tsal, S. Takata (2), M. Inul, F. Kimura (2), T. Sata (1)  
STC C,  40/1/1991,  P.95
Keywords: Process Planning, Milling
Abstract : This paper describes model based operation planning for pocket milling operations. The tool path and cutting conditions are determined based on the geometric model of workpieces and the physical models of the cutting process. The tool path is generated by using the Voronoi diagram of a cutting area. Cutting conditions to achieve the maximum metal removal rate are determined by evaluating the physical models of cutting torque, chatter vibration, and machining error. To maintain a favorable cutting state, the radial depth of cut is controlled by modifying the tool path distance at the circle path segment and by adding additional tool path segments at the corner. Examples are shown to demonstrate the effectiveness of the method.
A yugoslav approach to decision support for optimization of FMS technologies
L. Lukic, D. Polajnar, V. Solaja (1)  
STC C,  40/1/1991,  P.99
Keywords: FMS
Abstract : A generalization method of determining realistic machinability parameters in chip-removal cutting processes is presented in this paper. This method integrates generalized and verified machining functions with analytical dependences obtained from experimental data and machining procedures. Reliable and applicable technological models of machining processes are defined by this method, which are the base of a computer decision support system in the design and optimization of FMS technologies. The results are built into the relational database system and the algorithm for decision support system.
An atomistric analysis of nanometric chip removal as affected by tool-work interaction in diamond turning
N. Ikawa (1), S. Shimada, H. Tanaka, G. Ohmori  
STC C,  40/1/1991,  P.551
Keywords: Cutting, Micromachining, Accuracy
Abstract : This paper discuss the significance of the minimum thickness of cut which id defined as the minimum uncut thickness of chip removed from worksurface at a cutting edge under perfect performance of a metal cutting system. Following a brief look at the relation between the minimum thickness of cut and extreme machining accuracy attainable for a specific cutting condition, it is shown that a very fine chip the uncut this thickness of which is at the order of 1 nm is obtained in an experimental face turning by a well-defined diamond tool. To understand nanometric chip removal process, a computer simulation using an atomic model is made. The analysis of the experimental results aided by the computer simulation shows that, while the minimum thickness of cut is affected by the tool a workmaterial, interaction to a certain degree, it is more strongly affected by the sharpness of cutting edge and that the minimum thickness of cut may be at the order of 1/10 of the cutting edge radius.
Ultra-precision diamond turning of stainless steel by applying ultrasonic vibration
T. Moriwaki (2), E. Shamoto  
STC C,  40/1/1991,  P.559
Keywords: Ultra-Precision Cutting, Single Crystal Diamond Tool, Ultrasonic Vibration Cutting, Stainless Steel
Abstract : The paper presents experimental results of ultra-precision diamond turning of stainless steel. The steel cannot be machined normally by diamond tools due to excessive wear, although there are great demands for ultra-precision machining of the steel family. The ultra-precision diamond turning of stainless steel was realized by applying ultrasonic vibration of 40 kHz to the single crystal diamond tool in the cutting direction. The surface roughness of less than 0.03 ?m in Rmax is obtained. The cutting test results up to 1600 m in the cutting distance are also presented.

 STC Dn 

A CAD integrated "knowledge based system" for the design of die cast components
J. Corbett (2), J. Woodward  
STC Dn,  40/1/1991,  P.103
Keywords: Design, Expert Systems, Castings
Abstract : The paper shows haw knowledge based systems, and in particular features representation, can be applied in the area of design for manufacture to alert the designer of any potential production problems, before he commits his design to manufacture. Die casting was the subject for this initial research as it was a strategically important process in the collaborating company's drive to reduce timescales and costs while improving quality. The phases of knowledge acquisition, knowledge representation and the CAD customized modeler interface are described for the system which supplies appropriate design for manufacture expertise 'up-front' at the point of design.
Design for assembly within concurrent engineering
E. Molloy, H. Yang, J. Browne   / B.J. Davies (1)
STC Dn,  40/1/1991,  P.107
Keywords: Design, Assemblies, Concurrent Engineering
Abstract : Design For Assembly (DFA) is identified as an important strategy for the reduction of product manufacturing costs. In this paper the background to Design For Assembly (DFA) is described, and a method for the representation of DFA knowledge adopted. The problem of Computer Aided Assembly Process Planning CAAPP) is also addressed, and an approach_ using the disassembly sequence is developed using product information generated using a feature-based CAD system. This feature information is also used to generate a graph-type representation of the product structure for use in an integrated CAAPP/DFA system.
Feature-based reasoning in fixture design
W. Dong, W.R. De Vries (2), M.J. Wozny  
STC Dn,  40/1/1991,  P.111
Keywords: Design, Fixture, Feature
Abstract : Features or mechanical design are generally defined is entities which describe both the form and function of/ /the design. This geometric and process related design information facilitates the design of tooling and fixture; for manufacturing a part. This paper investigates the use of features for fixture design, concentrating on the selection of locating elements and the identification of locating surfaces or workpiece positioning.
Automatic generation of product disassembly sequences
A.K. Subramani, p. Dewhurst (1)  
STC Dn,  40/1/1991,  P.115
Keywords: Design, Service, Assembly, Disassembly
Abstract : Assessment of service difficulties at the concept stages of product design coupled with an existing methodology for estimating assembly difficulties would help in the assessment of life cycle costs. The authors are investigating procedures which can be used to assess service difficulties and costs at the early stages of product design. A central part of this work is generation of required disassembly sequences for identified service or repair items. This paper describes a mode of assemblies which as been developed for this purpose with the associated search algorithms. To facilitate the required search procedures, the concept of a disassembly diagram was introduced. The relationships between this diagram, the assembly model and the search procedures are illustrated in the paper by a simple example.
Design procedure of intelligent machines and its application ot AGV
Y. Furukawa (2), N. Moronuki  
STC Dn,  40/1/1991,  P.119
Keywords: Design, Intelligent Machine, Information
Abstract : This paper proposes a concept and procedure of intelligent machine design. First, a concept of functional design for each requirement is described. In this study, the information flow of the system is considered referring the human's action and information flow. Then. a concept and procedure to construct a hierarchical system is introduced in which each element's load balance is considered. In order to verify this concept, an intelligent AGV was developed. This AGV recognizes the operator's voice command, decides an action plan by itself, and travels autonomously recognizing the environment with ultrasonic sensors.
Conceptual design of control strategies for hot rolling
J.S. Gunasekera (2), J.C. Malas  
STC Dn,  40/1/1991,  P.123
Keywords: Conceptual Design, Hot Rolling, Thin Sheets
Abstract : This paper deals with the application of 'axiomatic' approach to the conceptual design of a hot rolling process. Functional requirements {FRs} of the rolling process are governed by the metallurgical and shape requirements of the product. Design parameters {DPs} which are capable of controlling the process in order to achieve the desired {FRs} are identified. A design matrix which relates {FRs} and {DPs} is then derived and re-arranged ro maintain independency of the parameters and 'decouple" the design. Results obtained using this approach will form a basis for subsequent, detailed design of the process.
A pattern directed design system for machine assembly
F. Kimura (2), H. Suzuki, I. Tanaka  
STC Dn,  40/1/1991,  P.127
Keywords: Computer Aided Design, Features, Routine Design
Abstract : A system is proposed to facilitate the pattern directed machine design process in which routine design of mechanical elements is often used as a vocabulary. The design knowledge about the routine design, which is found in handbooks or catalogs, is stored as design features. A design feature/ /consists of the parametric definition of its parts shapes and the knowledge for detailing those shapes. To represent machine assemblies designers locate design features in work space, and relate them with design constraints. The system determines the detail of design features so that the constraints are satisfied, and solid models of part shapes are generated. A prototype system is implemented on an object oriented language Flavor, and some examples are shown.
Design for manufacture analysis : early estimates of tool costs for sintered parts
W.A. Knignt (2)  
STC Dn,  40/1/1991,  P.131
Keywords: Design for Manufacture, Powder Metallurgy
Abstract : Early decisions on processing methods and part features should be based on quantitative assessments of manufacturing costs. This paper describes a methodology for determining tooling costs for processing parts manufactured by sintering from powder metals. This procedure is intended to be used at the early design stages when alternative part configurations and processes are being considered. The results of application to a range of parts are included. This procedure is included in a software tool for use by designers to facilitate early design decisions on part features and processing methods.
PDGL - An human and computer readable language for efficient feature based designing
F.L. Krause (2), S. Kramer, E. Rieger  
STC Dn,  40/1/1991,  P.135
Keywords: PDGL
Abstract : For high level and efficient computer aided design it is necessary to provide the possibility of object oriented modeling. A language has been developed to describe features in an object oriented manner including their technological semantics. The resulting generic feature templates are interpreted by the modeling system during runtime. Therefore the specific feature takes the actual design into account. By computing derivable parameters automatically, integrating related standard tables and by regarding design rules, features behave according to their associated semantics. During product gestaltung with features, the user works in his semantical environment and not only with geometric primitives. The concept for the feature design language as well as some examples demonstrating the advantages of the concept are presented.
A rule based systems approach to the design of manufacturing cells
A.K. Kochhar, H. Pegler   / J.A. McGeough (1)
STC Dn,  40/1/1991,  P.139
Keywords: Design, Cells, Systems
Abstract : This paper describes a three staged systems approach, and the associated rule based procedures, which may be used for the steady state design of assembly cells incorporating the highly effective and successful Just-In-Time philosophy. The approach involves the assessment of assembly alternatives, the comparison of capacity alternatives, and the specification of cells arrangement. The important rules, based on information elicited from experts in the design and implementation of assembly cells are described. The approach and the rules described make it possible to take account of the large number of the interrelated factors. The rules may be used on their own or as part of a computer based tool box provided to the manufacturing systems designers.
Integration of simulation, learning and optimization to support engineering design
S.C.Y. Lu (2), D.K. Tcheng, S. Yerramaredy  
STC Dn,  40/1/1991,  P.143
Keywords: Design, Simulation, Knowledge Processing Technology
Abstract : This paper presents a knowledge processing system, called AIMS (Adaptive and Interactive Modeling System), which integrates simulation, learning, and optimization techniques to perform multi-objective model formation and model utilization tasks. The system is aimed at improving the utility of simulation programs for analysis and synthesis during various stages of design. In this paper, we demonstrate the use of AIMS with an internal combustion engine simulator. A set of models, which trade off accuracy with speed, are induced by AIMS based on examples generated from the simulator. When comparing induced models with the original simulator, we observe orders of magnitude improvement in model's execution speed with only a minor compromise in model's predictive accuracy.
A framework for an object/rule-based automated fixture design system
A.Y.C. Nee (1), A.S. Kumar  
STC Dn,  40/1/1991,  P.147
Keywords: Jigs and Fixtures, Knowledge Based Systems, Design
Abstract : Fixture design has traditionally been regarded as a manual process due to extensive requirements of heuristic knowledge and skilled craftsmanship. This paper presents a framework for automated fixture design using a solid modeler, an object/rule-based expert system and X Window. Geometric and textual information are extracted from the solid modeler to determine the type of operation and number of set-ups required. Locating, supporting and clamping planes and points are identified using rule-based as well as mathematical analysis. The final output represents fixture assembly sequences and the feasibility for robotic assembly is also discussed.
Feature based part database design and automatic forming of part families for GT
B. Logar, J. Peklenik (1)  
STC Dn,  40/1/1991,  P.153
Keywords: Entity-Relationship Model, Relational Part Database, Feature Based Design, Binary Coding Matrix, Part Families
Abstract : The contribution deals with the feature based part database (engineering model) design, realized through the CAD program FAMOS. The system enables the forming of part families by automatic generation of the part binary coding matrix or part classification. The part database has a relational structure including the geometrical, dimensional, and tolerance features.
CSG representation as a basis for extraction of machining features
M. Shpitalni (1), A. Fisher  
STC Dn,  40/1/1991,  P.157
Keywords: images/cirpfichiers/annals/ CAD/CAM, Feature Extraction, Machining Features, CSG
Abstract : The process of converting a given design into the form of a raw_ stock minus a series of machining features is known as machining feature extraction. A method has been developed for extracting of machining features of different types: simple, compound, complex and nested. The proposed method is based upon extracting the disjointed machining regions comprising the total volume to be machined first, and then dealing with each disjointed machining region independently. The extraction of the machining regions is performed by manipulating the CSG tree representing the object, evaluating the various machining regions by using quadtree encoding, and pruning the CSG tree accordingly. As a result, compact CSG trees, each representing a machining region, are obtained. Analysis shows that the proposed method can successfully handle cases of feature extraction which are in general difficult to handle using other methods, particularly the cases of overlapping and nested features.
On the design process for customized products and demands upon a technical information system
E. Agerman   / G. Sohlenius (1)
STC Dn,  40/1/1991,  P.161
Keywords: Customized products, Design
Abstract : This paper deals with experiences from use of technical information systems, for design of products tailored to meet customer specifications and adapted to quality assurance standards like ISO 9000-9004. Implementation of computer support for calculation and design work had to follow stringent demands upon a well structured working procedure. The procedures for the handling of a contract for the design and supply of such customized products must prevent non-conformity at all stages from design through to servicing. The impact of these demands was of crucial importance for the creation of the Technical Information System.
Design of software system base on axiomatic design
S.J. Kim, N.P. Suh (1), S.G. Kim  
STC Dn,  40/1/1991,  P.165
Keywords: Software, Design, Axioms
Abstract : The ability to utilize the fully automated flexible manufacturing systems (FMS) or develop a reliable computer-integrated manufacturing (CIM) system will depend on our ability to develop reliable and reusable softwares for large complex systems on a timely basis. To date, software design has not gone beyond the ad hoc trial-and-error stage. Consequently, the development of software is slow, expensive, unreliable, and unmanageable. The purpose of this paper is to provide a scientific basis for designing software. The approach used here is the axiomatic design, which is based on two design axioms: the Independence Axiom and the Information Axiom. The axiomatic approach is based on the recognition of the following common elements in design: the existence of independent domains (i.e., the consumer domain, the functional domain, the physical domain, and the process domain): the need to map between various domains during the design process: the decomposition of the characteristic vectors (i.e: functional requirements, design parameters, and process variables) in their respective domains: the zig-zagging required between the domains for decomposition: and the need to satisfy the design axioms during the design process. The axiomatic approach discussed in this paper provides decision making tools for software design in addition to systematic means of knowledge and data representation, synthesis and analysis of software, and the construction of the module-junction structure diagram.
Discrete part design by taking manufacturing restrictions into account
F.L.M. Delbressine, J.A.W. Hijink   / A.C.H. Van der Wolf (1)
STC Dn,  40/1/1991,  P.171
Keywords: Design, CAD/CAM
Abstract : A design methodology has been developed which takes manufacturing restrictions into account in the design phase. This has been accomplished by defining manufacturable design transformations. This paper deals with manufacturable design transformations for a particular manufacturing technique i.e. milling operations. A typical example is shown to illustrate this approach.


How to make stereolithography into a practical tool for tool production
G. Bjorke (1)  
STC E,  40/1/1991,  P.175
Keywords: Stereolithography, Toolmaking
Abstract : In two large projects BRITE; INSTANCAN and Nordic funds for technology-industrial development: NORSLA we concentrate on the development of stereolithography {SLA} into a reliable tool production. The paper presents the results so far. It covers how to make models accurate enough, and how to interface SLA to CAD-systems using standard formals as VDA-FS, IGES, etc., withoutgoing via facets.
New coating technology for the manufacture of components made from new materials
P. Hancock   / P.A. McKeown (1)
STC E,  40/1/1991,  P.179
Keywords: Machining, Coating, New Materials
Abstract : This paper addresses the recent developments in coating technology and the way in which they can be used to manufacture components made from the never structural materials. Coatings with properties which can not be matched by the same material in bulk form are described and their use as surface coatings for high performance ceramics examined. The application of new coating technology so the manufacture of components made by hot isostatic pressing HIP is described and, in particular, the application to the processing of ceramic fiber reinforced metallic composites is highlighted.
Optimization of laser beam transformation hardening by one single parameter
J. Meijer (2), L. Van Sprang  
STC E,  40/1/1991,  P.183
Keywords: Laser, Hardening, Optimization, Residual Stress
Abstract : The process of laser beam transformation hardening is principally controlled by two independent parameters, the absorbed laser power on a given area and the interaction time. These parameters can be transformed into two functional parameters: the maximum surface temperature and the hardening depth. It has been proven that with a constant hardening depth the results (hardness, residual stress, etc.) can he optimized easily with respect to only one independent parameter, the maximum surface temperature, which is app lied directly in adaptive control strategies.
Ion beam machining of tungsten carbide chips - fabrication of fine patterns
I. Miyamoto, A. Shuhara   / N. Taniguchi (1)
STC E,  40/1/1991,  P.187
Keywords: Die, Ion Beam Fabrication, Cemented Tungsten Carbide Chips, Fine Patterns, Mask, Wet Etching, Lift Off, Surface Roughness, Flatness
Abstract : An ion beam fabrication technique using masks made by wet etching and lift off methods has been developed to fabricate fine patterns of several mm in depth and several tens mm in width into a die made of cemented tungsten carbide chips which is difficult to pattern by conventional mechanical machining methods, and also by chemical etching, electro-chemical etching and electro-discharge machining. By choosing tungsten carbide chios with fine grains of 0.7 mm and optium ion, beam machining conditions of the work-table being rotated at an ion of 0.1 mm in Rmax and flatness of under 0.5 mm was obtained.
Newly developed laser sublimating method for direct formation of conductor film on ceramic substrates
N. Morita, T. Watanabe, Y. Yoshida   / T. Nakagawa (1)
STC E,  40/1/1991,  P.191
Keywords: Laser Heating, Conductor film, Ceramic Substrate
Abstract : A new method for direct formation of conductor lines on ceramic substrates by laser sublimating was developed. This method involves the selective forming of aluminum thin layers by decomposing aluminum nitride ceramics in argon gas atmosphere with a Q-switched YAG laser. This aluminum layers can be employed as a catalyst in electroless plating. Nickel conductor lines with a specific resistance about 1/10^-7 Wm were directly and selectively deposited on the aluminum layer in nickel electroless plating solution. This technique will have the high possibilities to alter, repair and customize circuits in a single and one-step maskless process.
A study on laser enhanced plating
K. Horlo, T. Kasai   / A. Kobayashi (1)
STC E,  40/1/1991,  P.195
Keywords: Physical and Chemical Machining, Laser Enhanced Plating, Electroless Nickel Plating
Abstract : In this paper, laser enhanced plating, which forms a nickel film on a metallic substrate selectively with the aid of heat energy by laser irradiation is studied. A plating solution control system. which includes solution flow control and temperature control, has been provided so as to realize continuous plating. The characteristics of plated nickel films under some experimental conditions have been investigated. The adhesive strength between a plated film and a substrate and the strength of a plated film itself have been also evaluated.
Electrochemical surface finishing of tungsten carbide alloy
T. Masuzawa (2), M. Kimura  
STC E,  40/1/1991,  P.199
Keywords: Physical and Chemical Machining, ECM, Tungsten Carbide Alloy
Abstract : This paper deals with an experimental study on finishing the surface of tungsten carbide alloy. A special design of the/ /pulse train for alternate polarity ECM is proposed for realizing a uniform dissolution of tungsten carbine and for suppressing the dissolution of the tool electrode. The effectiveness was confirmed by applying the pulse on an EDMed surface. A smooth surface without heat-affected layer or cracks was obtained. The experiments also led to hints for selecting the electrode material.
Development of pocket-size-discharge machine
T. Higuchi, K. Furutani, Y. Yamagata, L. Takeda   / H. Makino (1)
STC E,  40/1/1991,  P.203
Keywords: Electrical Discharge Machining, Mechanisms, Piezoelectricity
Abstract : The size of a conventional electro-discharge machine is limited by its electrode-feeding mechanism which consists of ball screws, gears and motors. By applying Impact Drive Mechanism (IDM), which can move with fine step, utilizing rapid deformations of piezoelectric elements, to a new electrode-feeding mechanism, a pocket-size electro-discharge machine can be developed, which can be miniaturized to dimensions of 18xl4x68 mm. Its feeding step is variable from 0.02 up to 0.6 mm. The machining performance for micro holes is as good as that of a conventional electro-discharge machine. Various applications of the developed electrode-feeding mechanism are dismissed.
A new process of finish machining on free surface by EDM methods
N. Mohri, N. Saito, M. Higashi   / N. Kinoshita (1)
STC E,  40/1/1991,  P.207
Keywords: Electrical Discharge Machining, Finish Machining, Cusp Removal
Abstract : In this paper, a new process of finish machining on free-form surface is proposed. This process consists of cutting an electrode and a work by a machining center, removing cusps of the electrode and the work by EDM and finish EDM with powder suspended working fluid. Geometrical tracing of intersections method was used for the generation of CL data. In cusp removing process after milling by a machining center, EDM under high wear conditions was carried out. Powder suspended working fluid was used in finish EDM in order to break through the limit roughness caused by electrostatic gap capacitance. Mirror like 3-d surface was realized through a series of automatic processes by EDM methods.
A study of the effect of synchronizing ultrasonic vibrations with pulses in EDM
D. Kremer, C. Lhlaubet, A. Moisan (1)  
STC E,  40/1/1991,  P.211
Keywords: Electrical Discharge Machining, Ultrasonic Vibrations, Synchronization
Abstract : The paper deals with EDM assisted with ultrasonic vibrations of the electrode. A first part introduces the beneficial effect of ultrasonic vibrations: increased feed rate by a better flushing, particularly for difficult conditions such as finishing with narrow gap; lower damage due to heating (thinner/ /recast layer, increased fatigue life). This is a continuation of the paper introduced at CIRP 1989. A second part shows the results of an experimental investigation of the technique using a synchronization/ /of ultrasonic vibrations and EDM pulses. This allows knowing more about the relationship between the pressure in the bubble and the effect of the discharge. A theoretical approach is proposed to explain this phenomenon.
Improvement of EDM efficiency by supplying oxygen gas into gap
M. Kunieda, S. Furuoya   / N. Taniguchi (1)
STC E,  40/1/1991,  P.215
Keywords: EDM, Oxygen, Stock Removal Rate
Abstract : This paper describes a new method of EDM which is supplied with oxygen gas into the discharge gap, when a water dased dielectric is used. It is found that the stock removal rate is increased due the enlarged volume of discharged crater and more frequent occurrence of discharge. During the analysis and discussions, attentions are paid in the heat and force caused by the activated chemical reactions of oxygen.
On-Line monitor and control for wire breakage in WEDM
K.P. Rajurkar, W.M. Wang   / R.P. Lindsay (1)
STC E,  40/1/1991,  P.219
Keywords: Physical and Chemical Machining, Monitoring, Wire-Rupture
Abstract : Wire breakage (tool failure) is encountered in many industrial applications (e.g. cutting of complex contours) of Wire Electrical Discharge Machining (WEDM). This paper describes an on-line WEDM monitor, and proposes a control strategy to prevent wire rupture. The monitoring system detects the sparking frequency which is correlated with the wire breakage phenomena. A large number of sparking frequency data during the process has been analyzed. Features of the sparking frequency leading to wire breakage have been identified. The new control strategy proposes to control the sparking frequency at a constant level for avoiding wire rupture and improving productivity.


The effect of temperature on the coefficient of friction in flat rolling
J.G. Lenard   / S. Kalpakjian (1)
STC F,  40/1/1991,  P.223
Keywords: Forming, Hot Rolling, Friction
Abstract : While it is acknowledged that one of the most important parameters affecting the magnitude of the coefficient of friction in metal forming processes is the temperature. Relatively few experimental studies have bees published that detail their exact relationship. The objective of the present work is to develop the required data that will allow the choice of die frictional coefficient to be made with confidence. In the present study the effect of temperature on the roll separating forces, roll torques and forward slip are measured during warm and hot rolling of commercially pure aluminum strips. The magnitude of the coefficient of friction inferred by matching measured and predicted roil forces. The results indicate the m is indeed a strong function of the temperature. In general, increasing the temperature leads to higher values of the coefficient.
An interpretation of the speed dependence of the coefficient of friction under the micro-PHL condition in sheet drawing
A. Azushima, M. Uda, H. Kudo (1)  
STC F,  40/1/1991,  P.227
Keywords: Micro-PHL, Coefficient of Friction, Direct Observation, Sheet Drawing, Tribology, Hydrostatic Pressure
Abstract : In the previous work, the authors confirmed the occurence of the so-called micro-hydrodynamic lubrication mechanism using a newly developed sheet drawing apparatus with a transparent quartz die. In order to search possibility of this mechanism to reconcile low friction and smooth surface finish in metal forming operations, the speed dependence of the coefficient of friction is examined under the same experimental conditions. The increase in the coefficient of friction with increasing drawing speed is then interpreted in terms of the measured volume of the surface pockets trapping lubricant.
A friction sensor for sheet metal rolling
C. Nyahumwa, J. Jeswiet (2)  
STC F,  40/1/1991,  P.231
Keywords: Rolling, Interface Forces, Friction
Abstract : A sensor for measuring interface forces in the roll gap has been designed. It has been used to measure successfully, the interface friction forces in the cold rolling of 1100 aluminum. In order to be sure the friction forces measured at the interface are correct, the results are integrated across the billet surface and then multiplied by the torque arm. This quantity is then compared to the input spindle torque that is measured during the experiment. These results were found to be within percent of each other for reductions of 20%37; and 25%37;. The design of the sensor is described and the results are shown for reductions up to 25%37;, with particular emphasis upon the reductions of 20%37; and 25 %37;. The results are for the unlubricated rolling of 1100 aluminum.
Modeling the frictional boundary condition in material deformation
D. Duram, B.F. Von Turkovich (1), A. Assempoor  
STC F,  40/1/1991,  P.235
Keywords: Simulation, Metal Forming, Friction
Abstract : In the simulation of metal forming processes, the effect of friction at the boundary between the die and the workpiece presents a complex analytical problem. Consideration of the area of contact, the contact loads and the direction of material flow must be adequately handled for the die/workpiece interface. The present work discusses the development and use of realistic friction models at the interface which can be incorporated into the finite element analysis of large scale plasticity. Particular emphasis is placed upon the transition from sticking to sliding friction. The concern for the ability of the model to establish the location and the movement of multiple neutral points in complex geometries is also addressed, FEM and experimental work was conducted to evaluate the boundary behavior modeled using the theory of Amontons Law, the Law of constant Friction and the theory of initial sticking proposed by Bay, Wanheim et al. It was determined that the initial sticking theory best approximated the early stage of deformation of the experimental results.
Lubrication limits in backward can extrusion
N. Bay, S. Lassen, K.B. Pedersen, V. Maegaard   / T. Wanheim (1)
STC F,  40/1/1991,  P.239
Keywords: Forming, Cold Pressing, Lubrication
Abstract : The tribological conditions in backward can extrusion at the contact between the can wall and the punch land are very severe due to heavy surface expansion. In the present paper these problems are analyzed especially at low reduction (r < 50%37;) where they are particularly pronounced. The influence of degree of reduction, punch nose geometry, friction and strain hardening of the specimen material on the material flow is studied by experimental analyses in model material as well as steel. On the basis of these flow analyses the transition between sound flow and suction of workpiece material to the punch has 'been estimated as function of the above mentioned parameters. The local surface expansion inside the can and the resulting lubricant film distribution has been measured. The results point out that the punch design normally recommended is suboptimal at large reductions and inappropriate at small reductions. A proposal for appropriate punch geometry depending on the degree of reduction is given.
Neural networks for process planning of cold forging
K. Osakada (2), G. Yang  
STC F,  40/1/1991,  P.243
Keywords: Expert Systems, Cold Forming, Pattern Recognition
Abstract : The technique of neural networks is applied to an expert system for process planning of cold forging in order to improve the process generating speed. A three-layer neural network is used and the back-propagation algorithm is employed to train the network. By utilizing the ability of pattern recognition of the neural networks, a system is developed to relate the shapes of rotationally symmetric products with their preforms and forming methods. Average speed of process inference for the products which have similar shapes to the products used in the network training can be improved significantly by using the trained neural network system.
Automatic generation of NC Production plans in stamping and laser cutting
A. Raggenbass, J. Reissner (1)  
STC F,  40/1/1991,  P.247
Keywords: Cutting, Expert System, Tool Loading
Abstract : Using various stamping and laser cutting machines with a prescribed set of tools, sheet parts have been manufactured according to CAD drawings. In this work an expert system will be presented, that generates a complete NC production plan for stamping, laser cutting or for the process combination. The module of the system is the geometry processor, the decision module, the tool selection, the collision module, the technology processor, the nesting, the path optimization and the sequence of operations. The main points of the presentation are an algorithm for tool selection, the formulation and consideration of tool loading rules, as well as a fast algorithm of path optimization.
Prediction of cracks in sheet-metal forming with FEM simulations and FLD's
E. Doege (1), P. Groche  
STC F,  40/1/1991,  P.251
Keywords: crack, FEM, FLD
Abstract : Forming limit diagrams (FLD's) in connection with calibrated FEM simulations can serve as a powerful aid towards the prediction of cracks in sheet metal forming. The critical punch travel has been predicted with FLD's and FEM simulation with an error of only 3%37;. A prerequisite for the successful application of FLD's is the separation of deep drawing and stretching cracks. They differ in the dominating condition of friction between sheet and tools at the beginning of cracking. Friction conditions during deep drawing cracks and determined by sliding friction whereas stretching cracks are accompanied by sticking friction between sheet and tools.
Strain path dependence of flow curves
W.H. Sillekens, J.H. Dautzenberg (2), J.A.G. Kals (1)  
STC F,  40/1/1991,  P.255
Keywords: Forming, Flow Stresses
Abstract : This paper deals with the changes in flow behavior, resulting from abrupt changes in the strain path. The transitions tension-to-compression, tension-to-torsion and torsion-to-tension were investigated, using the plastic strain at the transition as a parameter. Three materials were selected for the experiments: CuZn37 brass, C22 steel and Armco steel. Results of the combined tests are presented and compared with the corresponding standard flew curves (from compression, tension and torsion test). A conventional flow function (Hollomon) is accommodated to record the observed flow curve changes. Metallurgical backgrounds are considered.
Mashy-state rolling of aluminium alloys and cast irons
M. Kiuchi (2), S. Sugiyama  
STC F,  40/1/1991,  P.259
Keywords: Mashy-State, Rolling, Aluminum Alloy, Cast Iron, Functional Sheet, Solid Fraction, Internal Structure
Abstract : Mechanical and metallurgical features of mashy-state (or mushy-state) rolling processes are investigated. Mashy-state rolling of aluminum alloy sheets and cast iron sheets are carried out and effects of rolling conditions, such as solid fraction (weight percentage of solid component) of workpiece and thickness reduction, on flow and deformation characteristics of liquid component and solid component at roll gap internal structure and mechanical property of rolled sheet are widely investigated. The results are as follows. (1) The rolling force decreases distinctively following to the decrease in solid fraction of workpiece. (2) When the solid fraction of workpiece is low, the solid and liquid components flow separately at roll gap. (3) In that case, the internal structure of rolled sheet differs completely from that obtained by hot rolling. (4) Mechanical properties of aluminum alloys and cast irons may he improved and new type of functional sheets of those metals can be manufactured by the mashy state rolling.
Microstructural evolution during hot rolling
A.S. Korhonen (1), A. Rantanen  
STC F,  40/1/1991,  P.263
Keywords: Forming, Hot Rolling, Finite Element Method
Abstract : Finite element modeling of the hot rolling of steel plates was studied. The finite element code ABAQUS was complemented by a recrystallization model called MICROPLA. It appeared that the rolling force as well as the final grain size and the yield strength of the plate could be predicted with a fairly good accuracy. To study the accelerated cooling after rolling, the phase transformations were taken into account approximately by considering the different cooling rates in the center and at the edges of the plate. The predicted distortion of the plate was reduced about tenfold after the phase transformations were taken into account.
Towards a capability for predicting the formation of defects during bulk deformation processing
A. Zavallangos, L. Anand (2), B.F. Von Turkovich (1)  
STC F,  40/1/1991,  P.267
Keywords: Forming, Finite Element Method, Defects
Abstract : A set of constitutive equations for large deformations of isotropic, thermo-elasto-viscoplastic, microporous materials, and a new fully-implicit, incrementally objective, fully-thermo-mechanically coupled, time integration procedure have been incorporated into a finite element computer program, and the program is used to study the formation of material related defects (e.g. surface and internal porosity/ damage shear bands) which may occur in various stages or representative bulk deformation processing operations.
Determination of instability in sheet metal based on the anisotropic yield ellipse
J. Danckert   / T. Wanheim (1)
STC F,  40/1/1991,  P.273
Keywords: Sheet Metal, Forming, Plasticity
Abstract : The paper presents expressions for the subtangents at the onset of diffuse, respectively local instability in sheet metal. The subtangents have been determined using definitions of the effective stress and the effective strain, which in case of uniaxial tension reduce to the true stress and true elongation strain. Using this approach, the material's stress-strain curve obtained in a uniaxial tension test. is directly applicable in the determination of the curves for diffuse and local instability.
A finite element analysis of high speed metal forming processes
J.F. Fontaine, J.C. Gelin (1)  
STC F,  40/1/1991,  P.277
Keywords: High Speed Forming, Finite Elements, Viscoplasticity, Rolling, Upsetting
Abstract : A finite element formulation to deal with the flow of metal that includes high speed effects is presented. The deformation process of the metal is treated using the rigid-plastic or the rigid-viscoplastic approach and the solution technique used includes convective and acceleration effects in the equilibrium equations of the problem. In the first part of the paper the mechanical aspects of high speed metal forming processes are analyzed, then the solution procedures using the finite element method are developed. An interesting version of the three-field approach is presented to obtain an accurate solution for the stress field. Then the last part of the paper presents the results obtained for the steady state wire-drawing process, the steady state extrusion problem, the steady state rolling problem and a deep drawing problem. The results obtained are compared with experimental ones and with results obtained from the quasi-static case. It is clearly shown that in some cases of industrial relevance, it is necessary to take into account of dynamic effects to obtain a good agreement with the experiments.
Deformation analysis of deep drawing by the finite element method
H. Darendeliler, B. Kaftanoglu (1)  
STC F,  40/1/1991,  P.281
Keywords: Forming, Deep-Drawing
Abstract : A Finite element method is developed to study the elastic-plastic deformation of sheet materials in the presence of large strains and large displacements. It is based on updated Lagrangian type formulation and membrane shell theory. The sheet is assumed to be isotropic and rate insensitive which obeys J_2 flow theory. The work-hardening characteristics of material and Coulomb friction between the sheet metal and forming tools are incorporated. The method is used for modeling partial deep-drawing with the appropriate boundary conditions. Numerical solutions are compared with the experimental results.
Process simulation of metal forming processes : some examples
M. Hermann, M. Wilhelm, p. Keck   / K. Lange (1)
STC F,  40/1/1991,  P.285
Keywords: Forming, Finite Element Method, Process Models
Abstract : A finite element program for the analysis of axissymmetric and three dimensional metal forming processes is presented. The underlying mechanical model is based on an elasto-plastic constitutive law for isotropic material behavior including work-hardening. Contact problems at the interface between workpiece and tool are handled by means of penalty method. The tool is assumed to be rigid. Thermal effects are negliged. The paper describes the application of the finite element code EPDAN to the simulation of different forming operations: upsetting test according to Rastegaev, rectangular tensile test, axissymmetric bulging pf thick-wailed tubes (liquid bulge forming) and bending in a V. shape die. As far as possible the computational results are compared to experimental data.
Forming aligned fiber composites into complex shapes
T. Gutowski, A. Tam, G. Drillon, S. Stoller   / N.P. Suh (1)
STC F,  40/1/1991,  P.291
Keywords: Composites, Forming, Differential Geometry
Abstract : Differential geometry theory is used to show how an ideal aligned fiber composite (incompressible, inextensible fibers, constant uniform spacing between fibers) must be deformed in order to make a part of complex curvature. Three fundamental results are obtained; the first two relate the required shears to the fiber curvatures (normal and geodesic), and the third, called the Gauss-Bonnet theorem, relates the shears to the Gaussian curvature of the part and the fiber orientation. Finally, it is shown how these results can be used to simplify experimental data.
Knowledge based systems and F.E. simulations in metal forming processes design : an integrated approach
N. Alberti (1), L. Cannizzaro (2), F. Micari (2)  
STC F,  40/1/1991,  P.295
Keywords: Cold Forming, CAPP, Expert Systems
Abstract : The automatic computer aided planning and design of cold forming processes includes several phases, among which the most important are the optimal choice of the forming operations sequence and, for each operation, the determination of the more suitable operating parameters. With this aim the Authors propose an integrated approach based or the preliminary choice of some feasible forming sequences, carried out by means of a knowledge-based system, and on the subsequent determination of the optimal one employing a finite element simulation of the process.
A generalized life-time model for cold extrusion tools
L. Cser (2), M. Geiger  
STC F,  40/1/1991,  P.299
Keywords: Forming, Extrusion, Tool-Life, Expert System
Abstract : It is very difficult to predict the expected life time at cold extrusion because of the complexity of the interchanges among the different kinds of failures and failure mechanisms. To the prediction of the most probably life time for a class of cold forming tools an expert system has been developed which takes into account the geometrical, mechanical and tribological boundary conditions and utilizes factory data and experience. In order to be able to handle the different mechanisms of failure it was necessary to work out a generalized life-time model of cold forming dies. The governing idea is similar on the state-space method used in the qualitative reasoning. All the damage mechanisms are active at the same time, but the life-time is determined by the dominant mechanism leading fastest to the total fail out of the dies. The role of the dominant mechanism can be taken over by other mechanisms during the exploitation of the die, depending on the changes in the state-variables. The expert system is based on the feature processing. The tool is derived into the elements carrying out only geometric information, but information about the loads and the possible failures also. The elements of the same tool parts are connected with each other by different type of contact an neighbors between the elements of different tools part.
Fracture mechanics analysis of extrusion dies
M. Geiger   / K. Lange (1)
STC F,  40/1/1991,  P.303
Keywords: Forming, Tool Life, Fracture, Simulation
Abstract : Premature tool failure caused by fatigue crack growth or wear is a severe problem to industrial application of metal forming technology. Better knowledge about manufacturing process, tool loading and fracture behavior is necessary in order to improve tool design. Process simulation applying Finite Element Method could offer a powerful assistance for process-adjusted tool layout. The paper will give some results of FE-simulation of tool loading and fatigue crack propagation in extrusion dies and some considerations about tool life prediction. A new approach to J-controlled fatigue crack growth under complex mixed mode tool loading will be presented.
Development of CAE system for auto-body panel forming die design by using 2D and 3D FEM
A. Makinouchi, E. Nakamachi, T. Nakagawa (1)  
STC F,  40/1/1991,  P.307
Keywords: Sheet Forming, Computer Aided Engineering (CAE), Finite Element Method
Abstract : An integrated CAE system for auto-body press tool design is discussed. The CAE system is required to predict forming defects by computer simulation and to save time and cost needed for tool design. This system consists of five models. The first module is CAD which describes tool geometry; the second module is data bases which provide experimental data; the third module is a pre-processor generating a finite element mesh in the sheet metal; the forth module is two elasto-plastic FE codes to simulate sheet metal forming processes; and the last module is the post-processor which displays the calculated results by computer graphics. Two elasto-plastic FE cods, ITAS and ROBUST, are introduced in the FE module. ITAS uses 2-D solid elements to simulate 2-D bending deformation, while ROBUST employs a membrane model to simulate fully 3-D sheet metal forming processes.
Flexible numerically controlled tool system for hydro-mechanical deep drawing
E. Von Finckenstein (1), M. Kleiner  
STC F,  40/1/1991,  P.311
Keywords: Deep Drawing, Toolmaking, Flexibility
Abstract : The development of a flexible, numerically controlled tool system for deep drawing and stretching is described. The tool system, whose idea is based on Japanese and American researches, consists of a matrix of 1089 rods, which form the deep drawing punch by adjusting each of them individually. After the workpiece, which is to be manufactured, has been constructed with a CAD-system, the control data for the tool adjustment control is generated automatically out of the workpiece geometry by a special software. The tool system is used with a conventional hydraulic press, with has an equipment for hydro-mechanical deep drawing.
A method of blanking from amorphous alloy foils using rubber tool
F. Takahashi, T. Nishimura, I. Suzuki   / H. Kudo (1)
STC F,  40/1/1991,  P.315
Keywords: Blanking, Amorphous Materials, Foils, Tooling
Abstract : In the conventional blanking method from amorphous alloy foils, the clearance between punch and die should be kept extremely small. Since it is difficult to make such a tool set in the case of large and complicate-shape products, we developed a novel method of blanking. The punch was made of rubber instead of steel and a strong counter force was generated by a rod type spring or by a hydraulic pressure unit. The relationship was investigated between the product quality and the process variables, e.g., the counter pressure, punch material and punch penetration into the die. The present method was found to press-work acceptable products from amorphous alloy foils and also to be applicable to blanking of complex-shape products such as motor stator lamination.
Computer aided wire drawing
A. Zompi (2), M. Cipparrone, R. Levi (1)  
STC F,  40/1/1991,  P.319
Keywords: Wire, Drawing, Simulation
Abstract : Current studies on mechanics of cold wire drawing provide a comprehensive picture, of the effects of main parameters on the basic process. However at production floor level multipass drawing still exhibits a number of tough problems. Scatter in wire properties, defects, lubricant decay, irregular die wear may affect product quality and upset production schedule. By combining experimental evidence with theoretical and numerical models of the basic friction and deformation process into a global description of multipass machine operation, taking into account stochastic process properties, production planning procedure may be effectively supported, and reliable guidelines for process control and trouble shooting are obtained.


Influence of up-grinding and down-grinding on the contact zone
J.G. Wager (1), D.Y. Gu  
STC G,  40/1/1991,  P.323
Keywords: Grinding, Temperatures, Cutting Forces
Abstract : The influence of up-grinding and down-grinding on the contact zone has been compared with respect to six factors: level and distribution of surface temperature, forces, roughness distribution, occurrence of visible burn, contact length and relationship of the entry region and the exit region. Though a better understanding of the influence of these two modes on the contact zone, some general influences about the effective difference between up-grinding and down-grinding are presented in this paper.
Force and chip formation in single-grit orthogonal cutting with shaped CBN and diamond grains
Y. Ohbuchi, T. Matsuo (1)  
STC G,  40/1/1991,  P.327
Keywords: Grinding, Micromachining, Superabrasives
Abstract : Single-grit orthogonal cutting text have been performed on a carbon steel with shaped CBN and diamond single grain (#20/24). The cutting test were carried out by means of a reciprocating surface grinder. The cutting and thrust forces were measured under different cutting conditions. Chip formation mechanism was also studied. Thus, the effects of cutting speed and rake angle on the forces or chip formation became clear for the two abrasive types. The CBN grain was much lower in cutting forces than the diamond grain, and the forces increased largely by changing a rake angle from ?45° to ?75°.
Grinding of transformation toughened Y-TZP ceramics
R. Krishnamurthy, L.M. Arunachalam, C.V. Gokularathnam   / V.C. Venkatesh (1)
STC G,  40/1/1991,  P.331
Keywords: Transformation Toughening, Grinding, Zirconia
Abstract : Developments in ceramics have introduced a nee class of ZrO_2 ceramics called as ceramic steel. By controlling the mol, percentage and particle size, a Zirconia-Yttria ceramic was developed which exhibits toughening by tetragonal to monocline transformation. The inserts made of TTZ (Transformation Toughened Zirconia) were ground for application as a cutting tool. During surface grinding, toughening of surface material was observed; the amount of transformation was more with CBN than diamond grinding, indicating the stress induced nature or transformation. This transformation has influences significantly specific grinding pressure, normal grinding force component and surface quality.
An attempt to predict residual stresses in grinding of metals with the aid of a new grinding parameter
B.W. Kruszynski, C.A. Van Luttervelt (1)  
STC G,  40/1/1991,  P.335
Keywords: Residual Stress, Grinding, Surface Integrity
Abstract : Residual stresses are considered as the most representative parameter of all properties in the surface layer created by grinding processes and which allow a relatively good assessment of the performance of ground parts. The damage caused by the creation of residual stress in the surface layer of metals has been analyzed from the point of view of the thermal aspects of the process with the purpose of finding a representative parameter which combines the most important grinding parameters and which is strongly connected with the residual stress created in the surface layer. Such a parameter may be useful when selecting grinding conditions of critical parts. The suggestion of such a parameter has been developed. The evidence - based on analysis of available data found in literature - of its good functional correlation to the residual stress generated in different workmaterials in different grinding operations is presented and discussed in the paper. It seems that the proposed new grinding parameter may be helpful in a better control of surface integrity in grinding in the industrial practice.
An advance in the modelling of thermal effects in the grinding process
W.B. Rowe (1), M.N. Morgan, D.A. Allanson  
STC G,  40/1/1991,  P.339
Keywords: Machining, Grinding
Abstract : The proportion of the grinding energy entering the workpiece may be analyzed either for the whole grinding wheel-workpiece contact zone or for the average grain contact zone which is two orders of magnitude smaller. An analysis which does not clearly apply to one zone or the other introduces conceptual difficulties since the relative speed seen by the workpiece is very different for the two cases. At the grinding zone level the workpiece sees a relative speed of Vw whereas at the grain level the workpiece sees a relative speed of Vs+/- Vw. An analysis has been presented for partitioning at the grain level which overcomes these conceptual problems. Result from the new model are compared with the results from other models.
Thermal aspects of grinding : the effect of heat generation at the shear planes
A.S. Lavine   / B.F. Von Turkovich (1)
STC G,  40/1/1991,  P.343
Keywords: Grinding, Temperature, Modeling
Abstract : The model of heat transfer in the grinding zone which had been previously developed by the author has been modified to account for the fact that some of the grinding energy is generated at the shear planes. Examples are given to evaluate how much error was incurred in making the earlier simplification that all the heat is generated at the wear flat areas. For finding with aluminum oxide wheels, it is found that the error is typically not huge, but may be significant, depending on the grinding conditions. For grinding with CBN wheels, however, the error is very important.
On performance of brazed bonded monolayer diamond grinding wheel
A.K. Chattopadhyay, L. Chollet, H.E. Hintermann (1)  
STC G,  40/1/1991,  P.347
Keywords: Grinding, Diamond Tools
Abstract : In recent years, in many applications, brazed bonded single laver diamond tools are getting preference over galvanically bonded counterpart because of their outstanding performance. High crystal exposure is reported to be one of the most distinguished features of the brazed tool. The present study, however, has revealed that commercially fabricated brazed tools do not necessarily provide high crystal exposure as claimed by the manufacturer because of accumulation of bonding material in the space between the grits during brazing. Performance of such commercially manufactured wheels, relative to that of brazed tools fabricated according to CSEM's new process, with improved uniformity of bond level and grit protrusion, is reported in this paper. Oxide ceramic and cast iron were used as work materials during grinding experiments.
Development of chipping-free dicing technology applying electrophoretic deposition of ultrafine abrasives
J.L. Ikeno, Y. Tani, A. Fukutani   / H. Sato (1)
STC G,  40/1/1991,  P.351
Keywords: Abrasives, Depotion, Brittle Materials, Chipping
Abstract : It is very important to decrease the amount of chipping in the dicing process brittle materials for the reduction of material loss and the improvement of surface integrity in the production of optical and electrical components. The use of ultrafine abrasives reduces the grain depth of cut which results in the minimization of subsurface damage. Thus, a new dicing technology has been developed by applying electrophoretic deposition of ultrafine abrasives. During the process, the abrasives cohered around a conductive thin blade used as the anode in an electric field and polished the side surfaces of grooves. Consequently, chipping-free dicing was accomplished and an optically smooth surface was obtained on the side surfaces of the groove.
A selftuning adaptive control system for grinding processes
E. Brinksmeier (2), C. Popp  
STC G,  40/1/1991,  P.355
Keywords: Grinding, Adaptive Control, Diagnostic Routines
Abstract : This paper deals with the development and use of an adaptative-control-system for the external grinding process. Because the behavior of the grinding process is substantially influenced by disturbance a selftuning controller is employed. A system identification procedure is used in order to allow a permanent adaptation of the controller to the changing process parameters. The change in the identified system parameters can also be used to diagnose process faults such as grinding wheel wear and to compensate for dimensional deviations due to elastic deformation of the workpiece-tool-machine system.
Monitoring and optimization of internal grinding process
I. Inasaki (2)  
STC G,  40/1/1991,  P.359
Keywords: Grinding, Sensors, Tool Life
Abstract : The grinding process is influenced by many factors such as grinding wheel characteristics, dressing conditions and, of course, grinding conditions. Therefore, it is difficult to perform the grinding operation in an optimum state. In this study, in-process monitoring methods using power and acoustic emission sensors are proposed to detect malfunctions in the internal grinding process. In addition, a new internal grinding cycle featuring rapid infeed is proposed to minimize the grinding cycle time.
Development of a simplified electrochemical dressing method with twin electrodes
K. Suzuki, T. Uematsu, T. Yanase, M. Honma, S. Asano   / T. Matsuo (1)
STC G,  40/1/1991,  P.363
Keywords: Grinding, Electrochemical Dressing
Abstract : The paper deals with a newly developed method for electrochemical dressing of metal bonded superabrasive wheels. In this method, alternating currant, derived from a wall outlet via an inexpensive transformer is supplied to a wheel through twin electrodes, hence a troublesome brush and an expensive DC power source are unnecessary. The process dressing of a wheel (d=200 mm) was accomplished within a few minutes. Inprocess dressing of a wheel resulted in lower grinding force, longer wheel life and higher grinding efficiency in grinding of ceramic materials and hard metals.
Development of productivity in aspherical precision machining with in-situ metrology
T. Nishiguchi, Y. Koizumi, Y. Maeda, M. Masuda, K. Nagayama   / K. Okamura (1)
STC G,  40/1/1991,  P.367
Keywords: Aspherical Machining, In-Situ Metrology, Form Error, Tool Setting Error
Abstract : This paper deals with the development of aspherical machining technology with in-situ metrology using the stylus method for the purpose of improving machining accuracy and reducing machining time. This technique is based on the in-situ measurement of machined geometrical accuracy, which makes it possible to calculate both the deviation of nominal tool diameter from the true one and the tool setting error in tool feed and traverse directions. The machining time can be reduced to a hail, or one-third with application of this procedure to either aspherical grinding or diamond turning.


Variable-grain cross-coupling controller for contouring
Y. Koren (1), C.C. Lo  
STC M,  40/1/1991,  P.371
Keywords: Control System, Controller
Abstract : The increasing trend for higher precision in manufacturing systems has brought an increasing interest in the design of servo controller. One of the most effective methodologies for contouring applications is the cross-coupling control (CCC). This paper introduces a new CCC method which utilized variable gains that are adjusted in process according to the shape of the part. The variable-gain CDC enables a contour error reduction of 3:1 to 10:1, depending upon the starting point and the resolution of the system as well as the contour clean.
Motion control of the direct drive actuator
H. Makino (1), T. Ohde  
STC M,  40/1/1991,  P.375
Keywords: Machine Tools, Dynamic Control, Actuator
Abstract : Two methods are adopted for the servo control of the Direct Drive (DD) actuator: (1) I-PD control for precise positioning with possible load fluctuations, and (2) P-'D + torque feed forward control for high-tact repetitious motion of stable load. In both methods, the selection of input motion curve is important to avoid residual vibration which is caused by the input signal components and by the output load. From this point of view, the cam curve control is used. Adjusting the parameters of the "Universal Cam Curve", several characteristic curves are obtained and tested for the control of the DD actuator. Experimental results are shown and discussed.
Experimental research on the linear motor micro-feed device with high frequency response, long travel and high accuracy
X.W. Wang, D. Wu   / Z.J. Yuan (1)
STC M,  40/1/1991,  P.379
Keywords: Micro-Feed, Linear Motor, Noncircular Cutting
Abstract : This pacer deals with the design and experimental research on the micro-feed device consisting of a linear motor, a laser interferometer and a high speed processor. Being of a closed-loop precision NC system, the device works mainly with the linear motor, which produces linear movement directly and has very fine servocontrol performance. This system is particularly suitable for a lathe to cut workpieces with noncircular cross sections.
Preload-control in ball screws - A new approach for machine tool building ?
H. Weule (1), H.U. Golz  
STC M,  40/1/1991,  P.383
Keywords: Machine Tool Building, Ball Screw, Preload-Control
Abstract : The preload in ball screws does not just have positive effects on zero backlash and rigidity, moreover it increases the friction loss which leans to heating and wear as well as a reduction of fatigue life of ball screws. With this background a system is introduced which allows variable set-up and control of the preload in ball screws. A ring-shaped piezoelectric translator is used as actuator, the design and characteristic features of which are described. The improvements obtained by the principle or preload-control are described by means of test results. Advantages for the manufacturing processes, such as an increase in cool life for machining with interrupted cat, are expected by the possibility of variation of camping and rigidity of the forward feed.
An advanced robot control system for manufacturing processes
G. Duelen (1), H. Münch, D. Surdilovic  
STC M,  40/1/1991,  P.387
Keywords: Robotics, Control System, Reference Model, Hybrid Position/Force Control, Contact Tasks
Abstract : Presented in this paper is an advanced robot control system which is used as a research and test environment. Its hierarchical and highly modularized structure, based on a new standard reference model proposed for telerobot control system architectures, allows customized development and implementation of different complex advanced control concepts and algorithms, including fusion of multisensor data. An overall system-oriented approach for sensor-driven manufacturing processes with industrial robots was developed and tested. A contact task was used to demonstrate the system performance.
Adaptive force control for robotic disk grinding
M.A. Elbestawi (2), K.M. Yuen, H. Dai, A.K. Srivastava  
STC M,  40/1/1991,  P.391
Keywords: Robots, Grinding, Adaptive Predictive Control, Force Control, Parametric Modeling
Abstract : In this paper, the design and implementation of an adaptive predictive force controller for robotic grinding are described. The force regulation is established by modifying, on-line, the robot's programmed position control commands. The experiments were conducted using an industrial robot equipped with a pneumatic grinder and a six degrees of freedom force sensor. Two predictive control laws, namely; Generalized Predictive Control (GO), and Extended Horizon Control (EH) are evaluated by simulation and experimentally. The control laws are designed based on accurate model(s) for the open-loop dynamics of the robot and grinding process, which are identified from experimental data. The results show that both controllers are able to effectively regulate the normal grinding force and compensate for force errors caused by step force disturbances and robot path tracking errors. A slightly better control performance was achieved, however, using the Generalized Predictive Controller.
Assessment of accuracy of robots in relation with geometrical tolerances in robot links
R. Weill (1), B. Shani  
STC M,  40/1/1991,  P.395
Keywords: Machines, Robots, Accuracy
Abstract : Absolute accuracy of robots has been plaguing designers of industrial robots since the beginning of the robot era. Several models of robot errors have been developed recently, but non is considering all types of errors occurring in he links and joints of robots. Therefore, a new model raking in account all errors of position and orientation at the end effector as a function of the geometrical errors in the links was developed. A graphical program enables a colored mapping of the errors in the whole workspace of the robot for typical nets of errors in the links. The relation between the error parameters in the model and the standardized definition of geometrical tolerances is established.
A predictive monitoring and diagnosis system for manufacturing
S. Spiewak   / M. Szafarczyk (1)
STC M,  40/1/1991,  P.401
Keywords: Machines, Predictive Maintenance, Microprocessors
Abstract : A systematic approach to the monitoring and diagnosis of machine tools and manufacturing processes is presented. This approach leads to a design methodology and a generic system structure for shop-floor applications. The essential components of this structure are discussed. Selected results obtained during several years of research illustrate crucial elements of the methodology. A modular and expandable system, whose design is based on the proposed methodology, is presented. This system, developed for a large car manufacturing company, has a hybrid structure composed of a traditional computer and a distributed parallel processing network.
Evaluating the cutting performance of machining centers
J. Tlusty (1), S. Smith, C. Zamudio  
STC M,  40/1/1991,  P.405
Keywords: Cutting, Machining Centers, Testing
Abstract : The paper discusses the theoretical background for Cutting Performance testing in a new ASME draft standard dealing with chatter and with effects of cutting force on workpiece accuracy. The most important measures for assuring that results be significant for comparative assessment and repetitive are the choice of tools and of the cutting speed. The tools arc so chosen as to generate "spindle modes" and not "tool modes". The spindle speeds are so chosen as to be above the range of "process damping" and below the range of significant "stability lobing".
Optimization of large composite structures
M. Weck (1), T. Nottebaum  
STC M,  40/1/1991,  P.411
Keywords: Design, Optimization, Fiberglass Reinforced Plastics
Abstract : The determination of optimal designs of large composite structures is a problem of high complexity and suggests the use of structural optimization methods. This paper presents a software system which applies numerical optimization algorithms to the design of large multilayer composites with respect to weight and displacement minimization. Design variables are lamina angles and thicknesses. For structural and sensitivity analysis the finite element method is used. The system is integrated into a CAE environment for ease of practical application. An example is given to show the performance of the presented system.
Machining high precision mirrors using newley developed CNC machine
K. Ueda, A. Amano, K. Ogawa, H. Takamatsu, S. Sakuta, S. Mural, A. Kobayashi (1)  
STC M,  40/1/1991,  P.555
Keywords: Diamond Turning, Grinding, Machine Tool, Form Accuracy
Abstract : An ultra precision CSC machine was developed for manufacturing high precision mirrors. The machine is capable of machining aspheric mirrors up to 650 mm in diameter and 250 mm in axial length. Laser interferometer feedback systems, with 2.5 nm resolution, are incorporated in both X and Z slide notions. Using this machine, a concave mirror, made from an electroless nickel plated aluminum material, was finished by diamond turning. The mirror had a form accuracy of less than 0.1 ?m P-V and 2 nm Ra surface roughness.
An active air journal bearing with ultra precision, infinite static stiffness, high damping capability and new functions
A. Shimokohbe, O. Horikawa, K. Sato   / H. Sato (1)
STC M,  40/1/1991,  P.563
Keywords: Air Bearing, Stiffness, Damping, Active Control, Piezoelectric Actuator, Positioning
Abstract : The aim of the paper is to develop an Active Air Journal Bearing (AAJB). AAKB is a rotary air bearing of a controlled type following features: (1) ultra precision, (2), infinite static stiffness, (3) high vibration damping capability, (4) new functions such as the positioning of the rotating axis and the dynamic stiffness control. Such features are realized by positioning the axis with an active bearing (AAB). AAB is composed of a static air bearing mechanism, a non-contact sensor, a piezoelectric actuator, a controller and an objective mass to be controlled, i.e. the axis. Then the compliance and the axis positioning characteristics are examined. Finally, the radial position of the axis rotating at 1000rpm is controlled and the rotation accuracy of the axis less than 25 nm is accomplished.
Feed servo control for ultra-precision turning machine
J.T. Li, X.C. Xu, B.L. Zhang (2)  
STC M,  40/1/1991,  P.567
Keywords: Feed Servo Control, Ultra Precision, Turning Machine
Abstract : This paper describes the high precision servo system and its mathematical model for the CNC ultra-precision turning machine which was developed by Beijing Machine Tool Research Institute (BMTRI ). With feed forward and variable gain control, back force compensation, mechatronic servo system can be simplified. The system provides 0.01 ?m resolution, 500 kpps travel frequency and 0.25µm positioning accuracy within 200 mm (X), 0.4 µm within 400 mm (Z).


Criteria for optimum layout design of assembly systems
C.R. Boër (2), J. El-Chaar, E. Imperio, A. Aval  
STC O,  40/1/1991,  P.415
Keywords: Optimization, Assembly Lines, Simulation
Abstract : The performance and the return of investment for Assembly Systems are very much dependent on the throuput of the system, on the utilization of the more important components (robots, AGVS, etc.) and on the reusing of these components in different configurations. The paper deals with the criteria for optimum layout design and how simulation is used to validate the criteria.
Operational dimension and tolerancing in CAPP
H.C. Zhang, J. Mei, R.A. Dudek   / F.W. Boulger (1)
STC O,  40/1/1991,  P.419
Keywords: CAPP, Automated Tolerancing, Operational Dimensioning and Tolerancing Chain
Abstract : The ideal output of operational sequencing of CAPP should include all start and end coordinates of tool movement for all operational dimensions rather than just give dimensions and tolerances unrelated to the coordinate system on the NC machine and leave additional work for the NC programmers. This paper deals with a new method of analysis of Operational Dimension and Tolerance Chain (ODTC) for CAPP systems. Based on discussion of previous works, apparent shortcomings are discussed and an extended approach provides ODTC to generate operational dimensions and tolerance for NC machines as a part of the decision methodology of CAPP systems.
Development of integrated process planning and monitoring system for turning operation
K.K. Cho (2), S.H. Lee, J.H. Ahn  
STC O,  40/1/1991,  P.423
Keywords: CAPP, Process Monitoring, Database, Knowledge-Based System
Abstract : This paper deals with the development of a prototype system which integrates process planning interfaced with CAD system and process monitoring for CNC turning operation through the interface and integration of data and knowledge processing. The integrated system is aimed for small and medium-sized machinery industry, and AutoCAD and CLIPS which can be run on personal computer are used as a CAD system and an exert system shell for knowledge-based process planning, respectively. The test results to show the system performance indicate that this prototype system works well for turning operation.
Structured modelling of manufacturing processes as NC-Data preparation
W. Eversheim (1), G. Marczinski, R. Cremer  
STC O,  40/1/1991,  P.429
Keywords: Process Planning, NC-Programming, CAD, CAPP, Information Modelling, STEP
Abstract : Process planning is a crucial link in the development of an integrated production environment. As information technology is a key for such an integration the modeling of manufacturing processes assumes a particularly important role. The present paper reveals a concept of modeling manufacturing processes for NC-programming applications. Today?s situation concerning CAPP and NC-data generation in view of CIM is analyzed. Requirements for the integrated modeling are derived. The concept for manufacturing process modeling is described, showing the close relation of functional and information modeling. Neutral interface aspects are covered by referring to the STEP-standard.
Optimization of set-up strategies for operating automated SMT assembly lines
K. Feldmann, N. Roth (2)   / K.G. Günther (1)
STC O,  40/1/1991,  P.433
Keywords: Optimization, Flexible Assembly, Surface Mount Technology, Set-up Strategies
Abstract : The state of the art in automation of he assembly of printed circuit boards (PCB's) is very advanced. But since the solutions realized up to now are mainly concentrated on the existing spectrum of standard components the introduction of the new technology of surface mounted devices (SMD) requires new approaches. The end time for a defined production volume of PCB's with SMD is decisive influenced by the choice of the set-up status of the assembly systems or assembly lines invoiced. The paper describes an approach to minimize the lead time by developing an optimization strategy for the initial set-up and subsequent chances in set-op of the components.
A new concept of CAPP based on flair of experienced engineers. Analyses of decision making processes of experimenced process engineers
T. Ihara, Y. Ito (2)  
STC O,  40/1/1991,  P.437
Keywords: Flair-Based CAPP, Experienced Process Engineer, Priority Rule
Abstract : in Decision-Making, Eye-Mark Camera Test, Model Pattern-Oriented Knowledge Base In using CAPP of knowledge-based type of the present, the required time for producing the process plan increases with the amount of the accumulated knowledge to be process. In contrast, process planning by the experienced engineer does not take so much time, and it appears to be in inverse proportion to tha amount of knowledge so far accumulated by this long experience. This paper describes some representative results of the questionnaire investigation on the priority rule in decision-making of the experienced engineer, after choosing the axi-symmetrical parts as objectives. Following it, an eye-mark camera test is carried out to ascertain the validity of the questionnaire investigation. Comparing these both the results along with those of non-experienced engineers, the essential features of decision-making are furthermore explicated. Based on the evidences obtained, a new concept of CAPP of flair-based type, i.e. that with model pattern-oriented knowledge base, is amso proposed in the present paper, and a part of it is actually produced.
A flexible real-time adaptive control system for turning
T. Lundholm   / B. Lindstr√∂m (1)
STC O,  40/1/1991,  P.441
Keywords: Optimization, Turning, Adaptive Control
Abstract : The paper deals with the organization of a new adaptive control system for turning and an integration framework for subsystems in the adaptive control system. Different monitoring, adaptive control constraint and adaptive control optimization functions are assigned to five subsystems. Monitoring and control of machining operations is based on measurements of machining characteristics and the subsystems induce a number of advanced sensor systems which are briefly descried. The stochastic nature of the machining process calls for real -time control of machining conditions. The subsystems are designed to operate in a relatively independent manner. Consequently, computer technologies for real-time and distributed control have been employed to realize a flexible modular system architecture for the adaptive control system. The layout of the system as well as the adaptive feedrate control strategy are presented.
A system approach for decision making in production grinding
S. Venk   / E. Merchant (1)
STC O,  40/1/1991,  P.445
Keywords: Optimization, Decision Making, Grinding
Abstract : A model of a potential Information Management Scheme to aid intelligent decision making for Production Grinding (IMSPG) is being proposed here. Its complete realization is a long term goal and involves implementation of the PBS (Prolog Based System), PCPlus, and grinding cycle modules of the proposed IMSPG model. Each module employs a unique approach for decision making related to its problem area. Actual industrial case studies are presented to illustrate the approach and working of the selected modules. Overall, industries implementing this model can be expected to realize significant benefits due to enhanced competitive decision making.
Semantic techniques for representation and identification of part families
G. Perotti (1), S. Tornincasa, G. Oberto  
STC O,  40/1/1991,  P.451
Keywords: Group Technology, Cluster Analysis, Feature-Based Models
Abstract : The paper deals with the automatic feature recognition of workpieces and families formation. To generate part families, the used approach utilizes a frame based representation system both for data and for features. A clustering method is used to take into account the morphology, the dimensions as well as the manufacturing sequences of parts. Being the procedure a self learning one, the introduction of new parts into the families is relatively simple.
5-axis control machining and grinding based on solid model
Y. Takeuchi, T. Idemura   / T. Sata (1)
STC O,  40/1/1991,  P.455
Keywords: Cutting, Grinding, 5-Axix Control
Abstract : The study deals with 5-axis control machining and grinding of workpieces with sculptured surface line impellers. The 5-axis control machining and grinding allows complex workpieces to be produced efficiently and accurately. Then, it is of importance to avoid the collision between tool and workpiece due to the arbitrariness of tool attitude. The system developed in the study generates the collision-free tool path for machining and grinding workpieces with sculptured surface, based on the CAD/CAM system employing the solid modeling technique. As a result, the validity of the system is experimentally confirmed.
A computer support system for manufacturing based on discrete event models
H.E. Islo, G. Sohlenius (1)  
STC O,  40/1/1991,  P.459
Keywords: Interactive design systems, Computerized Simulation, Human Factors Engineering
Abstract : This paper deals with the specification and implementation of a comprehensive computer support system to be used for the design and operation of manufacturing systems. Models of manufacturing systems which demonstrate requisite variety are considered to be the vital component of the computer support system. Therefore, we concentrate on the properties and characteristics which these models should embody. Among the advantages of this approach is the possibility to include human factors into the model and thus into the computer support system itself. Another is the possibility to use the models in an evolution strategy for optimization of system parameters.
Product life cycle economic models
V.A. Tipnis (2)  
STC O,  40/1/1991,  P.463
Keywords: Optimization, Life Cycle of Product and Process, Economic Models, Environmental Impact, Competitive Strategies, Concurrent Engineering, Penalty Costs
Abstract : A quest for a comprehensive life cycle economic model has been launched, prompted by the need to know the cost of making products and processes environmentally safe as well as the need to evaluate alternate product and process designs before the first production run is made. Classical manufacturing cost models, cost and management accounting models, and microeconomic models are not adequate. Recently introduced micro- and macro- economic models of manufacturing processes provide cut and sequence level analysis. The constraint (bottleneck) model demonstrates the importance of bottlenecks for minimizing throughput time. Activity Based Costing is a welcome development from accounting discipline. Significant progress has been made in determining the penalty cost when products and processes fail in field and in production. The real challenge is to develop the model in such a manner that it becomes a valuable tool for designing products and processes robust, competitive, and environmentally safe to operate, dispose and recycle.
Optimization of production flow patterns by use of intelligent CAD tools
A. Villa (2), C. Bandera  
STC O,  40/1/1991,  P.467
Keywords: Process Planning, CAD
Abstract : Optimization of production flow patterns results from scheduling the working activities to be performed by all Machining Centers (MCP) for processing all required parts. The complexity of this problem is prohibitive for obtaining a practically implementable solution. A decomposition-based approach is therefore highly recommendable. This paper presents a solution based on decomposition of the whole activity scheduling problems into a set of interconnected sub-problems, one for each part family. Since a part family cannot be processed "individually", i.e. on a proper cell, interactions among above mentioned sub-problems exist. The paper proposes a knowledge-based procedure using CAD tools, suitable for managing interactions and aimed at obtaining the best separation of sub-problems. An application of the intelligent CAD tool to a small-scale plant is also presented.
Communication and mapping systems for a free ranging automated guided vehicle
Z. Katz, J. Asbury   / R. Weill (1)
STC O,  40/1/1991,  P.471
Keywords: mapping
Abstract : The conceptual design and specific needs for a free-ranging AGV are presented. The work focuses on the physical development of such a unit with particular emphasis on communication between the off-board computer and on-board microprocessor for control and operation of the vehicle, A mapping system in real time for the potential path requirements is developed. Criteria for optimization and continuous path determination are tested. Simulation procedures are discussed.
Logistic analysis of production processes by operating curves
H.P. Wiendahl (1), T. Kuprat  
STC O,  40/1/1991,  P.475
Keywords: Operating Curves, Funnel Model, Throughput Diagram, Plant Layout
Abstract : In view of their logistic objectives, production control and plant layout are faced with an apparently insoluble conflict between short lead times and low work in progress on the one hand, and high capacity loading and due date performance on the other. The following paper slows that this opposing dependence is capable of representation and, above all, of quantification by operating curves. By resort to operating curves, the practitioner may evaluate the situation of production in real-life operational cases. To the theorist, these operating curves offer a universal method for modeling and evaluation of manufacturing processes.
Real time model reference adaptive control of 3D sculptured surface machining
K. Yamazaki (2), N. Kojima, T. Saito, C. Sakamoto  
STC O,  40/1/1991,  P.479
Keywords: Optimization, Adaptive Control, Sculptured Surface Machining, CAD/CAM, Geometry
Abstract : The paper deals with a new method for the productive machining of molds and dies which have an artistic geometry characterized by sculptured surfaces. The method developed is referred to as a 'Real Time Model Reference Adaptive Control' which autonomously adjusts the optimal feedrate such that the material removal should always be maximized with respect to the capability of a given tool and a given geometry of a workpiece by using a real time simulation of a software-based cutting process model. The practical feasibility of the proposed scheme has been verified through experiments performed on the prototyped system.
Non-contact 3D digitizing and machining system for free-form surfaces
K. Saito, T. Miyoshi   / H. Yoshikawa (1)
STC O,  40/1/1991,  P.483
Keywords: 3D, free-form
Abstract : A 3-D digitizing and machining system with a non-contact displacement sensor is introduced in this paper. This system consists of an NC milling machine, a personal computer to convert geometric model data into the NC driving data and a non-contact digitizing sensor for a free-form surface, This sensor, with a measuring range of 20 mm and resolution of 11 ?m/pixel, can measure the displacement of the free-form surface within an accuracy of ±50 ?m for a steep inclined surface up to ±75 degrees. The system can not only measure, but also machine the free-form surface such as 3-D model shapes for injection mold and pattern.
Sensor aided programming and movement adaptation for robot guided deburring of castings
G. Seliger, L.H. Hsieh   / G. Spur (1)
STC O,  40/1/1991,  P.487
Keywords: Cutting, Deburring and Cast Cleaning, Sensor Guided Robots, Sensorial Burr Detection, Process Modelling
Abstract : Automatically identifying burrs and planning robot trajectories for respective castings, geometrical and technological adaptation parallel to the process are tasks to be solved for flexible deburring automaton. Conditions of access and collision as well as different technologies e.g. milling, grinding or brushing must be considered for process design. A universal process model based on a frame concept with homogeneous transformation matrices has been applied for implementation or a microcomputer thus coupling robot control and sensorial devices. The paper describes a prototypical realization of deburring operations in a robot cell. Evaluation criteria for different technological approaches are given.


The processing of measured points in coordinates metrology in agreement with the definition of standardized specifications
A. Ballu, p. Bourdet (1), L. Mathieu (2)  
STC P,  40/1/1991,  P.491
Keywords: Dimensional Metrology, Coordinate Measuring Machines, Measurement Standards
Abstract : Increasingly, coordinate measurement techniques are used to ensure that mechanical parts conform to their geometric specifications. The analysis of the possibilities of the software in use brought to light an important number of tools, which however are not always adapted to the problem which is to be solved. Generally these tools only give one approximate answer to the problem set out by the verification of the dimensional and geometrical specifications. An indept study of the standards lead to the presentation, in this paper, of the problem typology, the two aspects of the verification of the specifications (measurement and control) will be presented and also the implication which these have on the solution algorithms. Finally, an attempt to define new processes giving the true value of the size to be verified is proposed. These proposals will he illustrated by an example and the numerical results will be analyzed and compared.
On the composite position tolerance for patterns of holes
E.A. Lehtihet, N.U. Gunasena   / A. Clément (1)
STC P,  40/1/1991,  P.495
Keywords: Composite Position Tolerance, Coordinate Measurement Techniques, Simulation of Production Errors, MMC/RFS Comparative Evaluation
Abstract : The verification of Composite Position Tolerances for patterns of holes was formulated as a non-linear optimization problem and a fast algorithm based on the method of feasible directions was developed for implementation on Coordinate Measuring Machines. The performance of the algorithm was tested and a simulation of composite position tolerance production was carried out. The influence of set-up errors, tool position errors, number of holes in the pattern and material condition specifications on the probability of producing a mod pattern were simulated.
Algorithm for the combined approximation of continously differentiable profiles composed of straight lines and circle segments
G. Goch   / H.J. Renker (1)
STC P,  40/1/1991,  P.499
Keywords: Coordinate Measuring Machines (CMM), Approximation, Deviation-Function
Abstract : A lot of workpieces and tools are manufactured by using copying turning machines. Many of them have profiles composed of straight lines and circle segments. Due to an number of reasons the profiles of the corresponding master workpieces or templates sometimes have to be changed slightly, specially the templates for forming tools (e.g. stamping dies for the manufacturing of ball bearings). In order to determine the actual geometry of a template (e.g. for a change of manufacturing to CNC-turning machines) the profile must be measured and approximated by a new profile consisting of straight lines and circle segments, which is continuously differentiable in its whole domain of definition. This paper describes an algorithm for the approximation of any profile composed of straight lines and circle segments in one step, i.e. the whole curve is not approximated sequentially segment by segment but in one iteration run thereby fulfilling the chosen norm in the complete domain. Approximation according to both the L_2 -norm and T-norm is possible and the profile is continuously differentiable at the joints between segments (excepted "edges" in the original profile). Basic mathematics will be briefly discussed and results obtained by measurements will be given.
Positioning accuracy of drilled holes
J. Kaminski, R. Crafoord / N. Martensson  / (1)
STC P,  40/1/1991,  P.503
Keywords: Drilling, Hole Position, Accuracy
Abstract : When selecting hole machining sequences, demands on positional accuracy determines the first drilling operation. The cutting data during the first revolution of the drill mainly determines the statistical deviation of hole position. The initial cutting process, when a drill approaches a workpiece, determines the lateral displacement of the drill and thus to a great extent the final position of the hole. With existing buckling theories, the deflection of the drill is partly explained. An experimental study of initial drill forces and positional deviations of holes, has given additional information on the influence of drill stability, surface inclination and quality, resulting in rules for a generative expert system for planning of operation sequences for hole machining.
Non-contact optical probe with holographic optical element
B.H. Zhuang, K.Q. Lu, J.H. Zhang, X.J. Wang, Z. Li   / G.X. Zhang (1)
STC P,  40/1/1991,  P.507
Keywords: Precision, Non-Contact Optical Probe, Holographic Optical Element (HOE)
Abstract : A smart non-contact optical displacement probe in which Holographic Optical Element (HOE) plays a major role is proposed. A HOE is basically a hologram which is a diffraction element recorded in a thin film. In this paper, the equation of the interference fringe patters of HOE is derived. The patterns of a CGH master are written by e-beam lithography with a resolution reduced ten times. The HOEs are duplicated as 5 mm in diameter. Several technique problems, such as double holo-knife-edge method, aspheric objective lens design and non-linearity correction are discussed. The experimental results are presented.
The resolution of positioning solids
A. Clement (1)  
STC P,  40/1/1991,  P.511
Keywords: Metrology, Resolution, Solid
Abstract : The paper deals with the generalization of the concept of the resolution of positioning. The study permits the calculation of positioning a solid at any point and any direction in space, given the resolution of the scale of the coordinate system, or the quality of the guidance system. Some practical examples will be presented.
Lenght bar and step-gauge calibration using a laser measurement system with a coordinate measuring machine
P.S. Lingard, M.E. Purss, C.M. Sona, E.G. Thwaite (1)  
STC P,  40/1/1991,  P.515
Keywords: Dimensional Metrology, Coordinate Measuring Machine, Laser Interferometer, Length Bar Calibration, Step-Gauge
Abstract : The most precise CMMs do not have the accuracy required to perform calibrations on length-bars and step-gauges except by recourse to conventional comparison techniques. This paper describes an economical method for substantially upgrading the single-axis measurement accuracy of a precision CMM using a laser interferometer. The measurement suits presented demonstrate that the system provides a practical and effective method to calibrate length-bars and step-gauges. The uncertainty of measurement derived from the analysis of errors conforms to OIML order of accuracy class 4 requirements.
A method for machine geometry calibration using 1D ball array
G.X. Zhang (1), Y.F. Zang  
STC P,  40/1/1991,  P.519
Keywords: Dimensional Measurement, Calibration, Coordinate Measuring Machine
Abstract : A method of machine geometry calibration using 1-D ball array is presented. A series of balls are equal spared fixed on a rigid bar. The spacings between balls are calibrated by a special laser interferometer. The position of the balls is sensed by a magnetic socket or a 3-D non-contact capacitive probe. The distinct feature of the hall array is that it gives 3-D positioning errors of the CMM simultaneously. It can be used for measuring all 21 source errors and for error compensation of CMM. The straightness errors are measured by using reversal method. The angular error notions are determined by measuring the displacement or straightness errors of two parallel lines. The squareness errors are determined by using the diagonal method. The 1-D ball array has low cost, high efficiency and high accuracy. It is expected to find wide applications in machine calibration and error compensation.
Development of a coordinate measuring system with tracking laser-interferometers
O. Nakamura, M. Goto, K. Toyoda, Y. Tanimura, T. Kurosawa   / K. Uehara (1)
STC P,  40/1/1991,  P.523
Keywords: tracking, laser-interferometers, measuring system
Abstract : A highly accurate co-ordinate measuring system for a large measurement area (larger than 1mx1m) is developed. The system consists of two target-tracking stations, each with a laser interferometer and a twin cube-corner mirror attached to a target. Since the co-ordinate of the target is computed from the radial distances between the target and the rotation axes of the tracking stations, the system can give position-measuring accuracy better than 1 µm , regardless of the absolute distances involved. Experimental comparisons between the system developed and a commercial co-ordinate measuring machine show that the position measuring accuracy of the developed system is better than 1.0 µm in a plane that is 600-800 mm away from the tracking stations.
Uncertainties in the acquisition and utilization of coordinate frames in manufacturing systems
Y.L. Shen, N.A. Duffle (2)  
STC P,  40/1/1991,  P.527
Keywords: Quality, Computer Integrated Manufacturing, Uncertainty
Abstract : Accurate and consistent transformations between design and manufacturing coordinate frames are essential for precision part production. These coordinate transformations establish surface position and orientation relationships as manufactured parts pass from design trough production processes to inspection and surface error analysis. Unfortunately, these coordinate transformations can be uncertain due to factors such as geometric form errors in workpiece reference surfaces, fixture locating point variations and coordinate measurement errors. A method for representing and estimating these uncertainties and their propagation through multi-stage manufacturing processes is presented in this paper. The method is applicable to systems with combinations of fixturing and coordinate measurements.
Elimination of geometrical errors by permutations - Application to a rotary table
T. Coorevits, J. David   / P. Bourdet (1)
STC P,  40/1/1991,  P.531
Keywords: Calibration of Rotary Table, Coordinate Measuring Machine, Reference Objet
Abstract : Errors elimination of a standard using sign change is a well-known method in order to define lacks of straightness or squareness of a measuring machine. The paper presents how it is possible to eliminate geometrical errors even on complex standards (with some symmetry conditions) by using a permutation technique. The method is presented from a mathematical point of view and is then applied to the analysis of two different rotary tables.
Cryogenic diamond turning of stainless steel
C. Evans   / J.B. Bryan (1)
STC P,  40/1/1991,  P.571
Keywords: Precision Engineering, Diamond Turning, Steel
Abstract : Tool wear is extremely rapid when ferrous materials are single point diamond turned. This paper reviews diamond tool wear mechanisms, showing that both fracture and chemical mechanisms may be important. The rate of all chemical reactions increases exponentially with temperature. Hence tool wear may be reduced significantly by machining at cryogenic temperatures, A cryogenic machining system comprising tool post and chuck with constrained liquid nitrogen flows has been built. Using this system a number of 35 mm diameter, 400 series stainless steel flats have been diamond turned. Surface finish is better than 25 nm Ra.


Determination of residual stresses in multi-materials, multi-layers pieces. Adaptation to ceramic coatings
M. Laracine, C. Bignon, M. Lormand, A.B. Vannes, C. Bedrin (2)  
STC S,  40/1/1991,  P.535
Keywords: Surfaces, Residual Stresses, Ceramics Materials
Abstract : The production of multi-lavers multi-materials coatings requires the knowledge of their mechanical behavior, and specially of the internal residual stresses fields. The method based on layers removal has been previously explained, for metallic pieces, the more usual removing mode is E.C.M. We have extended this model to the case of multi-materials coatings. Nevertheless, for ceramics materials (not electrical conductors), we had to use special cutting tools, after having verified that this process did not disturb significantly the considered stress field. We have thus analyzed various industrial samples, and explained the results with the blocks method.
Surface characterization and defects detection by analysis of images obtained with coherent light
P.M. Lonardo (2), A.A. Bruzzone, C. Gambaro, F. Parizzi  
STC S,  40/1/1991,  P.541
Keywords: Surfaces, Optical Measurement, Diffraction
Abstract : The paper presents a new approach to surface characterization by means of digital image analysis. The images, obtained through the diffraction of a concentrated beam of coherent light, exploring the surface, are the Fourier transform of the surface roughness. The features extracted from the images depend on the surface typology and local defects. The experimental work is a contribution to the development of surface quality control systems without direct contact.
Performance studies of uncoated, CVD coated and PVD coated carbides in turning and milling
V.C. Venkatesh (1), C. Ye, D.T. Quinto, D.E.P. Hoy  
STC S,  40/1/1991,  P.545
Keywords: Surface Integrity, PVD and CVD Coatings, Turning and Milling
Abstract : In turning, the three types of inserts initially produced workpiece surface finish of almost equivalent roughness but the CVD tool effected the brightest (maximum gloss) surface. In milling also the CVD tool gave the brightest surface. Specular reflectance is enhanced by the cutting edge profile which differs for turning and for milling. An image processing technique was developed which is able to distinguish very slight differences in surface gloss. Optical microscopy revealed irregular thermal cracks in CVD coatings but none in the PVD coatings. In turning the crack networks became elongated into comb cracks which protected the crater area. These observations can be rationalized in terms of high residual compressive stress in PVD coatings, desirable in milling wear mechanisms, as opposed to low tensile residual stress in CVD coatings. Cutting forces with PVD were also lower, and the secondary shear zone thinner, than with CVD tools.