Stream-of-variation theory for automotive body assembly
S.J. Hu   / Y. Koren (1)
STC A,  46/1/1997,  P.1
Keywords: Assembly, Dimension, Quality Assurance
Abstract : Manufacturing systems usually consist of processes and machines in a multi-leveled hierarchy. As a result, dimensional variation in the final product is accumulated as the product moves along the manufacturing system. This paper discusses the prediction and diagnosis of dimensional variation in a multi-leveled automotive body assembly system. By combining engineering structural models with statistical analysis, the evolution of the variability and stiffness characteristics of sheet metal parts is studied in terms of assembly configurations, i.e., serial or parallel. The diagnosability of serial and parallel assembly systems is evaluated. These results are integrated with correlation clustering to form a complete diagnostic strategy. Predicting and diagnosing variation in a multi-leveled manufacturing system constitute the two aspects of what we call the "Stream-of-Variation Theory."
Growth into miniaturization - flexible micro-assembly automation
G. Reinhart, M. Höhn   / J. Milberg (1)
STC A,  46/1/1997,  P.7
Keywords: Assembling, Automation, Micro-Handling
Abstract : The particular problems which occur during the assembly of miniaturized components result from their small dimensions.. their high sensitivity to damage and the micron-range precision required in the assembly process. Examples are provided to illustrate strategies for flexible micro-assembly automation: the implementation of new, problem-oriented assembly techniques and components and the optimization of conventional handling systems. The accuracy attainable by an automated micro-assembly system depends decisively on the ability to compensate for inevitable handling tolerances. Active as well as passive techniques for compensating tolerances during micro-assembly have been examined and their operating limits will be described. The precision assembly of a modern radio-controlled wrist watch will serve as an example of developments in assembly modules.
Co-operation of man and robot assembly - an evaluation of an industrial flexible assembly system
P. Holmstedt, L. Martensson, A. Arnström (2)  
STC A,  46/1/1997,  P.11
Keywords: Automation, Assembly Machine, Human
Abstract : In 1986 a totally new concept for flexible automatic assembly cells was launched within the research team "Assembly group", IVF/KTH, Department of Manufacturing Systems. A prototype, Mark II , was built and tested in the laboratory, and the industrial version, Mark II F, was installed in a company in 1991, where it carried out the automatic assembly of air motors for handheld tools. After five operational years, the system has been evaluated from a technical and human-factors point of view. The paper will discuss the whole development process, from the initial conceptual idea spawned by the university research group, to the experiences gathered by management and personnel of the system.
Assembly by non-grasping manipulation
T. Arai (1), J. Ota, Y. Aiyama  
STC A,  46/1/1997,  P.15
Keywords: Assembly Machine, Manipulator, Holonic System
Abstract : This paper deals with assembly and transportation of /non-grasping manipulations, /especially releasing. In releasing, a robot makes a part slide away on a plane. It has both advantages and disadvantages. Learning control using visual feedback is introduced so as to accommodate the uncertainty of the manipulation and environment. Experiments verifies that releasing is potent to construct a flexible transportation system. The research makes assembly more dexterous and flexible enough to make a Holonic Manufacturing System.


Predictive cutting model for forces and power in self-propelled rotary tool turning operations
E.J.A. Armarego (1), R.K. Katta  
STC C,  46/1/1997,  P.19
Keywords: rotary tool turning, cutting models, predictive force modelling
Abstract : A predictive model for the three force components and power in the ingenious self-propelled rotary tool turning operations is presented and experimentally verified for both TiN coated and uncoated carbide tools. The model based on the 'unified mechanics of cutting approach' and the fundamental rotary tool cutting processes reported earlier incorporates all the tool and cut variables. It is shown that this operation can be represented by a number of equivalent 'classical' oblique cutting elements of positive and negative inclination angles about an equivalent 'classical' orthogonal cutting element which controls the rotary tool speed and whose location is at the point where the torque on the rotary tool is zero for a frictionless tool spindle axis. The model predictions have encompassed and confirmed the few reported experimental trends noted in the literature and shown that the TiN coating only marginally reduces the power but with larger reductions in the radial and feed force components. The importance of modelling complex practical machining operations is highlighted in this work.
On the dynamics of chip formation in machinig hard metals
M.A. Davies, T.J. Burns, C.J. Evans (2)  
STC C,  46/1/1997,  P.25
Keywords: cutting, chip formation, modelling
Abstract : The results of orthogonal cutting tests on electroplated nickel-phosphorus (15%37; phosphorus) and AISI 52100 bearing steel are presented and compared. For both materials, chips become segmented at relatively low cutting speeds (0.3 m/s to 2 m/s) due to the onset of an oscillation in the material flow that is manifested in the repetitive formation of localised shear bands. The average spacing between the shear bands increases monotonically with cutting speed and asymptotically approaches a limiting value that is determined by the cutting conditions and the properties of the material being cut. The similarity in the behaviour of the two materials (which have significantly different microstructure) and the regularity of the shear band pattern observed in the chips provides strong evidence for a continuum mechanics model of the process. A simplified one-dimensional thermo-mechanical model of a continuous, homogeneous material being sheared by an impinging rigid wedge is developed to explain the observed behaviour. Numerical simulations of this model show that at low wedge speeds, material deformation reaches a thermo-mechanical equilibrium, in which material flow is homogenous and the stress, strain-rate and temperature fields reach a steady state behaviour that is constant in time (when viewed from a tool-fixed reference frame). As the wedge speed is increased, the stress, strain-rate and temperature fields become oscillatory, and the material flow becomes inhomogenous. As the speed of the wedge is increased further, the material shows repetitive shear localisation, with the distance between shear zones increasing montonically to some limiting value, as was observed in experiments.
Brittle/ductile transition phenomena observed in computer simulations of machining defect-free monocrystalline silicon
T. Inamura, S. Shimada (2), N. Takezawa, N. Nakahara  
STC C,  46/1/1997,  P.31
Keywords: cutting, brittle ductile transition,simulation
Abstract : By using renormalized molecular dynamics (RMD) proposed by the authors, computer simulations of machining defect-free monocrystal silicon of various sizes have been carried out to investigate crack initiation process. The results show that a defect-free monocrystal silicon can be machined in ductile mode to any scale in an absolute vacuum but exhibits brittle-ductile transition depending on the scale of machining under normal atmosphere. In this paper, detailed mechanism of the process of crack initiation is discribed together with the discussion of micro dynamics on why ductile mode machining is always possible either in small scale or in case of f.c.c. metals.
Continuous flank wear measurement of turning tools by integrated micro-thermocouple
C. Barlier, C. Lescalier   / A. Moisan (1)
STC C,  46/1/1997,  P.35
Keywords: cutting tool, flank wear, temperature
Abstract : This paper deals with a study of the correlation between wear and temperature in metal cutting. A thermocouple is implanted into the carbide insert of a turning tcol. The evolution of the temperature signal at the tool/workpiece interface nearest to the cutting edge is displayed continuously. The application of the analytical model of Kitagawa and al., related to a thermal approach of the cutting phenomenon, allows the establishment of an analytical model for the temperature measured by the probe depending on the flank wear. The model is verified by tests at constant sliding speed on carbon steel.
Nanocoatings on cutting tools for dry machining
F.M. Kustas, L.I. Fehrenbacher, R. Komanduri (1)  
STC C,  46/1/1997,  P.39
Keywords: coatings, tool, machining
Abstract : Novel material systems for coatings on cutting tools, towards accomplishing clean manufacturing, i.e. without the use of a cutting fluid, are presented. They involve use of multilayer nanocoating architectures of carbide/metal or solid lubricant/metal on cemented carbide tools by physical vapor deposition (PVD) process, namely, magnetron sputtering. By providing numerous (literally hundreds of layers) alternate nanolayers of hard and tough, hard and hard, or solid lubricating and tough materials, it is possible to take advantage of the unique properties of nanostructures, namely, higher hardness, higher strength, higher modulus, higher wear resistance, higher fracture toughness, higher chemical stability, and reduced friction than their counterparts where the coating layer thickness is in the micrometer range. Various features of these coatings are discussed from the point of view of their application in dry machining.
A new advanced ceramic for dry machining
N. Narutaki (2), Y. Yamane, S. Tashima, H. Kuroki  
STC C,  46/1/1997,  P.43
Keywords: ceramic, tool, machining
Abstract : Concerns toward safety of the work environment as well as the environment in general are compelling industry to adopt 'green' or 'dry' machining, i. e. without the use of any cutting fluid. Since, some of the benefits of the cutting fluids are not going to be available in dry machining, need exists for the development of a more refractory, tougher, chemically wear resistant, and hard cutting tool materials. In this paper, the synthesis and evaluation of a new alumina ceramic tool material using very pure (99.99%37;) and submicron grain size (0.22 µm) alumina powder with practically no binder sintered at low temperature (1230°C) (i.e. without the need for HIP'ing) are presented. This material is found to be stronger and harder than conventional HIP'ed alumina ceramic. The new alumina ceramic was found to be more wear resistant and fracture resistant (against both mechanical and thermal shock) than conventional alumina in dry turning and milling of gray cast iron and S45C carbon steel.
A sensor integrated tool for cutting force monitoring
M. Santochi (1), G. Dini (2), G. Tantussi, M. Beghini  
STC C,  46/1/1997,  P.49
Keywords: tool condition monitoring, turning, cutting force measurement
Abstract : This paper describes the development of a new concept of cutting tools using strain gages for the measurement of forces in turning operations. The basic idea is the integration of the sensor within the tool shank, in order to obtain a system which is easy to use, easy to install and capable of transmitting data to the CNC through wireless equipment. In particular, the output signal of the measurement bridge is amplified and sent to an external data acquisition system by infra-red transmission. The present paper reports the design principles and the results of some machining tests illustrating the behaviour of the tool in different cutting conditions.
In-process monitoring method for machining environment based on simultaneous multiphenomena sensing
H. Shinno, H. Hashizumz   / H. Sato (1)
STC C,  46/1/1997,  P.53
Keywords: cutting, in-process monitoring, multifunctional sensor
Abstract : The successful implementation of intelligent manufacturing systems requires in-process monitoring of the machining environment. The monitoring system should be capable of extracting multifaceted information about the environment. However, most current systems are based on single phenomenon monitoring, so their effectiveness is quite limited. In this paper, a new multifunctional in-process monitoring method has been proposed. This method, based on simultaneous multiphenomena sensing, can monitor multidimensional responses simultaneously. Through experiment and simulation, it has been verified that the method is effective and applicable to monitoring in a machining environment.
High speed milling of dies and molds in their hardened state
M.A. Elbestawi (1), L. Cheng, E. Becze, T.I. El-Wardany  
STC C,  46/1/1997,  P.57
Keywords: milling, dies and mold, cubic boron nitride (CBN)
Abstract : This paper presents an experimental investigation of high speed milling of dies and molds. Several critical issues involved with the high speed milling of H13 tool steel of hardness up to 55 HR., have been studied and explained from a detailed analysis of experimental observations. The experiments were performed using several grades of PCBN ball-nose end mills with various edge preparations. The effect of different process parameters on the tool performance and the surface finish produced was also investigated. The cutting parameters involved were; cutting speeds in the range of 220 to 1320 m/min, feed variation from 0.0254 to 0.1 mm/tooth, axial depth of cut from 0.625 up to 2 mm, and radial width of cut of 0.254 mm. During the preliminary experimental investigation, the tilt angle was kept constant at 10 degrees. Several tests were conducted to study the effect of the different tool path directions on the cutting tool performance. Dry and wet cutting conditions were used and the effect of coolant on the tool life was also determined. The optimum cutting conditions have been specified based on the modes of tool failure, tool life and surface integrity produced.
Burr formation in drilling miniature holes
J.M. Stein, D.A. Dornfeld (1)  
STC C,  46/1/1997,  P.63
Keywords: burr, formation, drilling
Abstract : The exit burrs in the drilling of precision miniature holes of diameters less than 1 mm are of interest. The burrs from these processes can be difficult to remove. This paper describes the results of a study on the burr formation in drilling miniature holes. Most existing studies focus on holes in the 3 mm to 12 mm size range. This data is not transferable to smaller diameter holes. We report here on the study of burr height, thickness and geometry observed in the drilling of 0.91 mm diameter through holes in stainless steel 304L. The sensitivity of feed, speed and-drill wear as well as the exit surface geometry (i.e. for intersecting holes) was determined. A proposal for using the drilling burr data as part of a process planning methodology for burr control is presented.

 STC Dn 

Co-operative design, manufacturing and assembly of complex products
G. Seliger (2), H. Karl, H. Weber  
STC Dn,  46/1/1997,  P.67
Keywords: co-operative, design, assembly
Abstract : As customer requirements rise and time to market shrinks the need for global sourcing of development, manufacturing, and assembly capacity increases. This paper presents a method far integrating design and manufacturing engineers from different companies into a virtual value-adding team. The method is based on network theory using circuits to describe the flow of information originating from customer requirements. These circuits sustain the context of specific activities to the overall task during requirements analysis, design, and system integration. A blackboard model based on the combination of these circuits together with design structure matrices visualizes and guides the course of action curing a product development project. T his blackboard enables international development consortia to work jointly on new products and processes in a selforganized manner with limited effort for project management. The design of a public transport system serves as an example to illustrate this method.
An integrated modular design methodology for life-cycle engineering
P. Gu, M. Hashemian, S. Sosale   / E. Rivin (1)
STC Dn,  46/1/1997,  P.71
Keywords: design, module, methodology
Abstract : Modular design seeks to develop products with distinct detachable modules for rapid product development, easy recycling, possible reuse of long-lasting modules, efficient upgrading, reconfiguration and other life cycle engineering objectives. However, each objective may require a different modularization. In this paper, we present an integrated modular design methodology for achieving multiple objectives. The methodology identifies the factors related to the objectives, relates these factors to design components through interaction analysis, and clusters components into modules using a genetic algorithm based technique. A case study is included to illustrate the methodology and the algorithms.
Design of systems
N.P. Suh (1)  
STC Dn,  46/1/1997,  P.75
Keywords: design, axioms, system
Abstract : Engineering projects, including those 'n manufacturing, involve systems from design to construction to operation. The most important aspect is design since system performance depends on the quality of design Mechanical systems design is complicated by difficulties in modeling, interplay of hardware and software, lack of scale-up rules, and the inclusion of human operators. Traditionally, systems have been designed based on know-how and trial-and-error, however, this empiricism can lead to costly mistakes. In this paper, a rational means of designing systems based on axiomatic design is discussed. It presents the procedure for systems design and a representation technique for system architecture.
Methodology and product model for integrated design using a multiviews system
S. Tichkiewitch, M. Véron (1)  
STC Dn,  46/1/1997,  P.81
Keywords: design, integration, product
Abstract : A methodology of integrated design is presented, based on the co-operative work between the partners of the life-cycle of the product. A product model, which is a link between a knowledge model and a data model, accommodates specific decisions of each participant in a multi-view system. Two exchange modes are available to the users : a formal one is the standard network between computers and gives access to a common product database and an informal one that uses a multi-media network in order to permit dialogue between participants. The prototype of such a design modeller is realized with an object oriented language.
Automatic reasoning for design under geometrical constraints
M. Shpitalni (1), H. Lipson  
STC Dn,  46/1/1997,  P.85
Keywords: CAD, conceptual design, geometry constraint
Abstract : Parametric design is very stable but requires a predefined dimensioning and ordering scheme, thus limiting flexibility and precluding sketch input. Variational geometry design, while general and flexible, necessitates intensive use of numerical solvers to solve many simultaneous nonlinear equations. Frequently the solvers cannot solve these equations. A new system, based on an original theory for automatic constraint analysis, has been developed for solving sets of two-dimensional geometric constraints in product design. The proposed system offers the flexibility of variational based design along with the stability of parametric design. The solution strategy is based upon breaking down the problem into a sequence of construction steps. When no sequential construction is found, auxiliary geometrical constructions are automatically generated based on rules for relocating constraints. Thus, an apparently simultaneous constraint set is converted into a set that can be constructed sequentially by decomposing strongly connected components of the original constraint graph. This new approach has been implemented in a system for designing sheet metal parts.
A model fusion approach to support negotiations during complex engineering systems design
S.C.Y. Lu (2), D. Li, J. Cheng, C.L. Wu  
STC Dn,  46/1/1997,  P.89
Keywords: modeling, system, design
Abstract : Computer models have been playing important roles in modern design, particularly at the component and subsystem levels. As competition increases, the challenge of design has shifted from individual components to overall systems. Alternative paradigms, different models and new approaches for using these models are needed to support system designs. This paper presents a "Model Fusion" approach to enable a new paradigm which views engineering design as a collaborative negotiation process. The "Model Fusion" approach fuses (or integrates) separate design and analysis models into a cohesive set of hierarchical empirical models to allow for explicit trade-off between competing modeling objectives, AIMS (Adaptive and Interactive Modeling System), an integrated empirical modeling tool with multiple learning and decomposition algorithms, is used to implement the "Model Fusion" approach. A real world application example of engine combustion chamber design, drawn from the automotive industry, is included to demonstrate the paradigm, approach, application and impact of this research.
Enhanced rapid prototyping for faster product development processes
F.-L. Krause (2), M. Ciesla, Ch. Stiel, A. Ulbrich  
STC Dn,  46/1/1997,  P.93
Keywords: design, rapid prototyping, CAPP
Abstract : Rapid Prototyping (RP) is useful in the fast production of physical prototypes and therefore constitutes a key element in the optimization and abbreviation of product development processes. To increase the accuracy and decrease the fabrication time of prototypes, an RP-Toolkit was developed supporting the overall CAPP process. The RP-Toolkit provides functional modules for repair of surfaces, technological planning of various RP processes as well as mechanisms for realization of STEP-based process chains. An essential aspect is the user-driven definition and adaptation of technological parameters to meet prototype requirements. Improvements in prototype quality are gained by use of process-specific production strategies. The build time of prototypes can be reduced using functions for adaptive slicing of precise BREP models.
Modeling in reverse engineering for injection molding analysis of 3D thin objects
A. Fischer (2), A. Smolin  
STC Dn,  46/1/1997,  P.97
Keywords: reverse engineering, molding, modelling
Abstract : Reconstructing a 3D sampled object into a computerized model is an essential part of reverse engineering. Applications such as casting and injection molding, however, also require a more abstract mid-surface representation for analysis. Reconstructing a mid-surface from a thin object is known to be difficult and time consuming. In this paper, a reverse engineering method is proposed for simultaneously reconstructing a 3D object and its mid-surface. The object and the mid-surface models are created so that their mutual relations enable subsequent interactions between design and analysis, needed according to simulation results. The stages in modeling the reverse engineering object and its mid-surface are: (1) sampling and filtering points through a data reduction algorithm; (2) recognizing dominant pairs of boundaries; (3) parametrizing object boundaries and finding parametric correlations between them, according to mid-surface definition; and (4) reconstructing a 3D object and its mid-surface. Error analysis, results and examples will be demonstrated.
Allocation of geometric tolerances : new criterion and methodology
A.O. Nassef, H.A. ElMaraghy (1)  
STC Dn,  46/1/1997,  P.101
Keywords: design, tolerancing, optimization
Abstract : This paper presents a new approach to the synthesis of geometric tolerances in the design process. In the published literature minimum cost has been the main criterion for tolerance allocation. Although this is satisfactory for dimensional tolerances, extending it to geometric tolerances presents a major drawback. The reason is that for each feature the number of combinations of tolerance types is large This paper presents a novel approach to the tolerance allocation problem that consists of 2 steps: (i) the manufacturing processes that minimize the production cost are chosen, then (ii) the types and magnitudes of geometric tolerances are optimized using genetic algorithms to reduce the probability of rejecting good parts or accepting bad parts during inspection, where a bad part is a one which will cause a violation of the assembly functional requirements.
Cost decision support in product design
A. Liebers, H.J.J. Kals (1)  
STC Dn,  46/1/1997,  P.107
Keywords: cost estimating, design
Abstract : The constraints addressed in decision making during product design, process planning and production planning determine the admissible solution space for the manufacture of products. The solution space determines largely the costs that are incurred in the production process, in order to be able to make economically sound decisions, costing data support must be integrated into the decision making processes. Regarding product design, the designer must be supplied with transparent costing data, that is ready for direct application. In this paper a functional architecture for costing data support during product design, as well as a corresponding data structure are presented.


High-pressure water peening-a new mechanical surface strengthening process
H.K. Tönshoff (1), F. Kroos, C. Marzenell  
STC E,  46/1/1997,  P.113
Keywords: water peening, residual stress, fatigue strength
Abstract : Water peening with pressures up to 100 MPa has been developed as a new mechanical surface strengthening process. The high-frequent impact of water drops on the surface of steel components causes local plastic deformation. As a result, high compressive residual stresses are induced in the surface-near layers. The special characteristic is that surface roughness and topography show only negligible modifications, so water peening can be used as a finishing process_ Due to the beneficial modifications in the surface-near material, fatigue strength significantly increases. The water jet's high geometrical accessibility predestines this new process for treatment of complex geometries.
Temperature of work materials irradiated with CO2 laser
T. Ueda, K. Yamada, K. Nakayama (1)  
STC E,  46/1/1997,  P.117
Keywords: laser beam machining, temperature, measurement
Abstract : Temperature of a workpiece irradiated with CO_2 , pulse laser, which is one of the most important factors for deciding the suitable conditions. In the cleavage cutting of brittle materials and the forming of sheet metals, is investigated experimentally and theoretically. The surface temperature is measured by a new type of Infrared Radiation Pyrometer using a fused fiber coupler. This pyrometer makes it possible to measure the flush temperature of a very small object without emissivity influencing the results. The temperature distribution in the surface layer of the workpiece is calculated numerically using FEM. The energy absorptivity of the workpiece is obtained by comparing the experimental results with the calculated ones.
High performance hydraulic valves welded by laser
M. Cantello (2), L. Bonello, G. Fontana, Z. Li  
STC E,  46/1/1997,  P.123
Keywords: laser beam machining, welding, quality assurance
Abstract : The Hydraulic valves require a high precision in dimension tolerance and absence of any defects for the high stress levels involved in the services of these components. A laser welding technique for the fabrication of hydraulic valves is presented, in which the butt welds joining AIS1304L to AIS112L13 were performed in such a way as to control solidification cracking and microfissuring. Metallurgical analyses revealed that both solidification cracking in the fusion zone and microfissuring in the heat-affect zone result from S, Pb, P contained in AIS112L13. A 0.12 mm off-set of the laser beam towards AIS1304L and an impingement angle of 15° with respect to the fit-up face of butt joints can produce sound welds on hydraulic valves made of 0.9 mm thick AIS1304L and AIS112L13. Tests on mechanical properties of the hydraulic valves revealed goodstrength, welds, high repeatability, and reliability of welding parameters adopted. A high accuracy seam tracking sensor, coupled with an on-line monitoring system, has been developed for process control and quality assurance.
Experimental study of the basic process mechanism for direct selective laser sintering of low-melting metallic powder
Y.A. Song   / W. König (1)
STC E,  46/1/1997,  P.127
Keywords: rapid prototyping, laser, sintering
Abstract : Due to the still limited mechanical properties of the materials which can be processed using industrially available rapid prototyping techniques, work is currently being undertaken to develop methods of manufacturing metallic prototypes directly. This paper reports on the process development of Selective Laser Sintering (SLS) for direct sintering of bronze as a low-melting metallic powder on a laboratory test facility. The experimental investigations with single spots, lines and layers on the powder bed indicate successful direct sintering of bronze powder without polymer binder or preheating. Besides the process parameters such as laser beam power, scanning speed and hatching distance, material parameters such as particle size distribution exert an influence on the melting behavior and should, therefore, be considered in terms of further process development.
Development of a droplet-based manufacturing process for freeform-fabrication
C.A. Chen, J.H. Chun   / G. Sohlenius (1)
STC E,  46/1/1997,  P.131
Keywords: rapid prototyping, deposition, processing
Abstract : Droplet-Based Manufacturing processes are now widely used in many industrial applications, including spray forming and rapid prototyping. Application of these processes to freeform fabrication, however, has been greatly hampered by the lack of accurate control over droplet generation and droplet deposition. In order to overcome such shortcomings, a high-precision, uniform-droplet deposition process has been developed. This paper presents the design rationale for the process and its use to determine a key process parameter: the in-flight droplet liquid fraction.
Fabricating metal objects using layer manufacturing technology and powder metallurgy science
J. Bakkelund, R. Karlsen, OE. Björke (1)  
STC E,  46/1/1997,  P.135
Keywords: rapid prototyping, sintering, metal
Abstract : In order to produce metal objects using Layer Manufacturing Technology, a new fabricating method is introduced by the authors. The layers in the new layer manufacturing process are generated by attracting metal powder to a charged photoreceptor under the influence of an electrostatic field, whereupon they are deposited one by one on a building table. After each deposit operation the layer of loose powder is consolidated using simultaneous pressure and sintering. This paper studies the layer generation system and the consolidation system, and investigate the results from these two systems. The present work proves that the new layer manufacturing process has the potential to become a manufacturing system capable of direct fabrication of objects in metal.
Forced discharge dispersion by dot-matrix method
N. Mohri (2), K. Furutani, K. Shirai, T. Enami  
STC E,  46/1/1997,  P.139
Keywords: electrical discharge machining (EDM), surface, servomechanism
Abstract : The quality of the surface machined by electrical discharge machining (EDM) depends on the degree of discharge dispersion. In this paper a dot-matrix EDM with scanning motion is proposed in order to realize rapid prototyping by EDM and to control the discharge position in real machining. The machining process by the dot-matrix method is similar to the printing motion with a dot impact printer. The developed machining unit has six electrode feeding devices each of which controls the position of a thin wire electrode independently by inchworm mechanism with piezoelectric actuators. Discharge current is supplied to each wire electrode also independently in order to realize complete discharge dispersion. 3 dimensional shape with crack-less surface is machined by scanning motion of the unit.
Electrical discharge machining in gas
M. Kunieda, M. Yoshida   / N. Taniguchi (1)
STC E,  46/1/1997,  P.143
Keywords: EDM in gas, die sinking, oxygen gas, oxidation, tool electrode wear, tool path
Abstract : In this paper, we show that electrical discharge machining (EDM) can be achieved in gas. With the help of a high-pressure gas flow supplied through a thin-walled pipe electrode, the molten workpiece material can be removed and flushed out of the working gap without being reattached to the electrode surfaces. The greatest advantage of this technique is that the tool electrode wear ratio is almost zero for any pulse duration. Hence a 3D shape can be machined very precisely using a special NC tool path which can supply a uniform high-velocity air flow over the working gap. Furthermore, the material removal rate is improved as the concentration of oxygen in air is increased, due to oxidation of the electrode materials.
WEDM adaptive control with a multiple input model for identification of workpiece height
K.P. Rajurkar (2), W.M. Wang, W.S. Zhao  
STC E,  46/1/1997,  P.147
Keywords: wire EDM, adaptative control, identification
Abstract : The variation in power density during wire electrical discharge machining (WEDM) results in reduced productivity and wire rupture. This paper presents a WEDM adaptive control system that optimizes on-line the sparking frequency by estimating the workpiece height with a new multiple input model. This model describes the dynamic and stochastic relationships between average gap feedback voltage and spark frequency and machine table feed rate. Extensive experiments have been carried out to verify the new model. The proposed system correctly identifies the workpiece height and avoids the sudden rise in the estimated height found in existing system.
Micro-linear motion bearing produced by anisotropic etching of silicon
N. Moronuki, Y. Furukawa (2)  
STC E,  46/1/1997,  P.151
Keywords: micro-linear bearing, anisotropic etching, friction
Abstract : This paper demonstrates the applicability of silicon anisotropic etching to the production of linear motion bearing. Machining accuracy of this etching depends not on the copying rule but the crystal regularity. As a result, accurate shapes such as V-grooves can be machined without precise control. The etched V-grooves are applied to the linear bearing system whose slider size is of the order of sub-millimeters and its stroke is about 3mm. First, the geometrical accuracy is evaluated. Then, the slider is driven by an actuator and the frictional force was measured. The coefficient of friction exceeds 3 in this case. Finally, the possibility of larger scale and more precise application is discussed.
Magnetic dispersion of micro particles using magnetic fluid - application to texturing process for magnetic rigid disk -
N. Umehara, K. Kato, K. Suzuki   / A. Kobayashi (1)
STC E,  46/1/1997,  P.155
Keywords: roughness control, micro plastic deformation, aluminium alloy
Abstract : In order to make well-arranged asperities on Al-alloy substrates of magnetic rigid disk as a texturing process, a new texturing method using magnetic fluid and magnetic field was developed, and its fundamental properties were shown. By applying magnetic field and normal load to the magnetic fluid including 4 ?m SiO_2 micro particles in the gap between the Al-alloy substrate and the glass plate, well-arranged micro particles were indented to the substrate and then made well-arranged asperities. It is concluded that magnetic field controlled the density of micro particles and the distance between micro particles well.


Determination of the r-value using automatic tensile test equipment
J. Danckert (2), K.B. Nielsen  
STC F,  46/1/1997,  P.159
Keywords: uniaxial tensile test, sheet metal, anisotropy
Abstract : When the r-value of sheet material is determined using automatic tensile test equipment, it is required by the norms that compensation for the elastic strains is made. In Stahl-Eisen Prüfblatt 1126 a compensation method is suggested:, however it is believed that this method is wrong. The paper proposes a compensation method and it is verified experimentally, that the proposed method yields a r-value which is almost identical to the r-value obtained from measurements carried out on the tensile test specimen in unloaded conditions.
New model of flow stress under cold forming conditions
P. Huml (1), D. Zonghai, Y. Wei  
STC F,  46/1/1997,  P.163
Keywords: cold rolling, wire drawing, cold forging
Abstract : Prediction of flow stress under forming conditions is commonly based on an explicit formulation of the flow stress mode': The flow stress is in this case expressed as a function of strain, strain rate, temperature, more seldom or structure. Such formulations make it difficult to predict the flow stress under forming conditions for different strain paths and also wren the strain rate and/or temperature varies during the deformation. This paper is aimed at describing a new model of strain hardening applied in metal forming analysis. This model allows better prediction of flow stress under cold forming conditions. The application of the incrementally formulated flow stress mode' is exemplified for prediction of met 3' flow. loads and temperature distribution -n cold forming processes.
Springback evaluation in fully 3-D sheet metal forming processes
F. Micari (2), A. Forcellese, L. Fratini, F. Gabrielli, N. Alberti (1)  
STC F,  46/1/1997,  P.167
Keywords: springback, bending, FEM
Abstract : In the modern manufacturing industries the knowledge and proper control of the sheet metal springback after forming is a fundamental aspect in the achievement of near net shape stamped parts. In this paper an effective springback prediction in some fully three-dimensional stamping processes is carried out. Such a prediction is based on a combined approach in which an explicit finite element code has been employed to simulate the forming phase while a traditional implicit procedure has been used to analyse the springback phase. The results obtained have been compared with a set of experimental tests and an excellent correlation between the predicted and experimental data has been found.
New developments for the qualification of technical surfaces in forming processes
M. Geiger (1), U. Engel, M. Pfestorf  
STC F,  46/1/1997,  P.171
Keywords: topography, rolling, forming
Abstract : In modern sheet metal forming, blank topographies are characterized by various quite different and rather sophisticated structures. This is due to the various deterministic or semi-deterministic methods of surface texturing produced by skinpass rolling. The conventional surface parameters determined from profile data are not capable of characterizing such surfaces, in particular with respect to their functional behavior. Thus, there is a strong demand for the development of new parameters which can only be determined via the measurement of area. With special respect to the application of deterministically textured topographies in metal forming, appropriate 3d surface parameters can be derived from the mechanical rheological model recently developed at the Institute of Manufacturing Technology. These are the maximum ratio of closed void area and the closed void volume, both of which result from a special evaluation of the bearing ratio curves. Industrial applications show that these parameters can be related to the functionality of the surface and hence may be regarded as very suitable for the characterization and qualification of complex surface structures.
Topography deformation of sheet metal during the forming process and its influence on friction
D. Schmoeckel (1), M. Prier, J. Staeves  
STC F,  46/1/1997,  P.175
Keywords: shit metal forming, tribology, topography
Abstract : The potential offered by modern texturing technologies for sheet metal cannot be fully used due to the fact that the characteristics of topographies optimised for tribological conditions are unknown. Besides experimental examinations, the development of new topographies requires an understanding of the basic phenomena of topography. Simulation of the material deformation occurring in the topography during the forming process using 3D finite element models provides results that cannot be obtained by measuring techniques. The simulation is complemented by measuring the topography before and after the forming process. Based on these results, optimised topographies and new 3D roughness parameters for the characterisation of their tribological properties are achieved.
Effect of glass lubricant behavior on the surface quality of extrudates in glass lubricated hot extrusion
D. Damodaran, R. Shivpuri (2)  
STC F,  46/1/1997,  P.179
Keywords: hot extrusion, glass lubrification, surface quality
Abstract : In glass lubricated hot extrusion, the behavior cf the glass lubricant is quite sensitive to process conditions and die design. The use of improper conditions can lead to surface defects. The typical thickness of the glass film is very small (? 40 microns), making measurement difficult and numerical analysis of lubricant behavior impractical. A mathematical model for glass lubrication is presented which enables an analysis of the effects of processing conditions on the thickness, flow stability and supply of lubricant over the stroke of the extrusion press. Correlations are drawn between predictions of lubricant thickness and flow stability and experimental observations of extrudate surface quality. Thus, this model can be used in the determination of optimum operating conditions for glass lubricated hot extrusion.
Flow simulation of semi-solid forging by FEM
N. Kim, J.H. Yoon, D. Li, S.I. Oh (1)  
STC F,  46/1/1997,  P.183
Keywords: semi-solid forging, simulation, flow stress
Abstract : The flow behaviour of semi-solid material is outlined and discussed. A representation of flow stress for AI-2024 in the semi-scud state and a numerical algorithm for updating the solid fraction during forging are proposed. Flow simulation by the finite element method in closed die forging to fabricate an automobile part has been performed and compared with experimental results. The information obtained from the simulation results are utilized in designing the preforms.
Simulation of metal flow and fracture-applications in orthogonal cutting, blanking and cold extrusion
E. Ceretti, E. Taupin, T. Altan (1)  
STC F,  46/1/1997,  P.187
Keywords: finite element method, plasticity, fracture
Abstract : This paper summarizes the work done or, the prediction of the ductile fracture initiation and propagation in plastic deformation processes. A commercial finite element code has been modified and fracture criteria have been implemented for the study of material separation. In particular, ductile fracture is simulated by deleting the mesh elements. Cracking starts when the element damage value reaches the "critical value", determined by experiments. The program has been tested on several plastic processes, such as orthogonal cutting, blanking and cold direct extrusion. The predictions show a good correlation with experimental results in terms of crack propagation and capability to predict internal defects.
Analysis and design of multi-blow hammer forging processes by the explicit dynamic finite element method
D.Y. Yang (2), Y.H. Yoo  
STC F,  46/1/1997,  P.191
Keywords: hammer forging, process analysis, dynamic FEM
Abstract : In the present work the numerical simulations of multi-blow hammer forging, as a high-velocity impact deformation phenomenon, are described. The explicit time integration finite element method is used to compute the workpiece deformation. The effects of strain hardening, strain rate hardening and thermal softening are considered. Through the simulation of copper blow test, the developed program has been verified. As an industrial example, multi-blow forging of a turbine blade using counterblow hammer has been simulated. Through the simulation of turbine blade forging, it has been shown that the developed explicit finite element program can be successfully applied to simulation of other practical industrial parts.
Numerical analysis of cross shear plate rolling
W. Zhang, N. Bay (1)  
STC F,  46/1/1997,  P.195
Keywords: rolling, shear zone, numerical analysis
Abstract : The rolling process is widely applied for industrial production of metal plates. In conventional plate rolling the two work rolls are rotating at the same peripheral speed. By introducing a specific difference in the speed of the two work rolls, cross shear rolling is introduced forming a central shear zone between the forward and backward slip zones in the deformation zone thus lowering the rolling load. A numerical analysis of the cross shear rolling process is carried out based on the slab method adopting Wanheim and Bay's general friction model. The pressure distribution along the contact arc in the roll gap, the position and the size of the shear zone and the rolling load are calculated. Experimental results are presented verifying the calculations. The numerical analysis facilitates a better understanding of the mechanics in cross shear plate rolling.
Experimental and finite element analysis of capabilities and limits of a combined pneumatic and mechanical deep drawing process
M. Kleiner, A. Gartzke, R. Kolleck   / E. Von Finckenstein (1)
STC F,  46/1/1997,  P.201
Keywords: deep drawing, pneumatic forming, process analysis
Abstract : In the last ten years various forming processes with working medium - like hydraulic counter-pressure deep drawing (also known as hydromechanical deep drawing) or hydroforming - are more and more used for different applications especially in the automotive industry. Recently another process was proposed: the so-called pneumomechanical deep drawing combines a preforming, which uses a gaseous working medium like air, carbon dioxide or nitrogen, with a deep drawing in the same, specially designed tool system. The paper presents research work on process and tools as well as on their application to sheet metal forming. Process capabilities and limits are analysed through forming experiments, strain measurements based on an optical system and through corresponding finite element calculations.
Pulsating blankholder forces in the deep draw processes
K. Siegert (2), M. Ziegler  
STC F,  46/1/1997,  P.205
Keywords: deep drawing
Abstract : In this paper the effects of pulsating blankholder forces in deep draw processes for sheet metal parts are discussed. Areas with and without tangential compressive stresses in draw part flanges, which are located between the binders, are discussed separately. Areas without tangential compressive stresses can be simulated by a special friction strip-draw test using a pulsating normal force ( representing the blankholder force ). Investigations using this equipment show that by pulsating blankholder forces it is possible to avoid galling and to reduce the friction force. Areas with tangential compressive stresses can be simulated by deep drawing axisymmetric cups using a pulsating blankholder force. Investigations with this equipment show that without increasing the danger of wrinkling the friction forces can be reduced by pulsating blankholder forces. This enlarges the gap between the wrinkling- and the fracture-border for the blankholder force over the stroke.
Precision forging of spline by flashless die forging with axially driven die
K. Osakada (1), X. Wang, S. Hanami  
STC F,  46/1/1997,  P.209
Keywords: cold forging, spline, forming pressure
Abstract : In cold forging, a high, forming pressure is required to fill the billet material into the corners of the die cavity due to the high flow stress of the steels. To reduce the forming pressure, a method employing an axially driven die is proposed. In this method, the die is moved in the axial direction while the billet material is squeezed by the punch. The corners cf the die cavity are filled easily by the help of the frictional force over the billet-die interface. The effectiveness of this method for precision forging of a spline is examined by model experiments. The results show that the forming pressure is significantly reduced compared with the conventional closed die forging or the floating die method.
Optimized kinematics of mechanical presses with non-circular gears
E. Doege (1), M. Hindersmann  
STC F,  46/1/1997,  P.213
Keywords: press, gear, kinematics
Abstract : The quality of parts manufactured using metal forming operations depends to a large degree on the kinematics of the press ram. Non-circular gears with a rotational-angle-dependent speed ratio in the press drive mechanism offer a new way to obtain those stroke-time behaviours we aim at as an optimum for the various metal forming operations in terms of manufacturing. The paper explains the principle using a prototype press which was built by the Institute for Metal Forming and Metal Forming Machine Tools at Hanover University. It will present the kinematics as well as the forces and torques that occur in the prototype. Furthermore, the paper demonstrates using one example of deep drawing and one of forging that the press drive mechanism with non-circular gears may be used advantageously for virtually all metal forming operations.


Improving workpiece roundness through centerless grinding cycle planning
S.S. Zhou, G.C. Petrosky   / R. Lindsay (1)
STC G,  46/1/1997,  P.217
Keywords: centerless grinding, process simulation, cycle optimization
Abstract : In centerless grinding, achievable workpiece roundness is directly related to the cycle length selected for the grinding process. This paper proposes a systematic approach to minimize workpiece roundness error by optimizing the cycle length. In the paper, the transient characteristics of the rounding process is first investigated. It was found that minimum workpiece roundness error can be obtained when the initial roundness error is effectively suppressed but the lobing pattern is not yet fully developed on the workpiece surface. Then, a computer simulation method is introduced to optimize the grinding cycle length in terms of minimum workpiece roundness error for both plunge and through-feed centerless grinding processes. The concept of an average growth rate is introduced to assess the lobing stability in through-feed centerless grinding.
Grinding at very low speeds
E. Brinksmeier (2), C. Schneider  
STC G,  46/1/1997,  P.223
Keywords: gear finishing, grinding process, modelling
Abstract : In recent years a new method for hard gear finishing that produces a favourable surface texture and possibly allows gear correction was introduced. Material removal by the shave-grinding or gear honing process is the result of a rolling and sliding movement between the geared workpiece surface and the abrasive grits bonded in a resin, vitrified or metal tool matrix, shaped similar to an internal gear wheel. A laboratory set-up based on a grinding process with speeds between 0.3 m/s and 3 mls was designed in order to investigate fundamental process behaviour and to compare the knowledge gained with conventional grinding processes. Moreover recommendations for improvement of the shave-grinding process could be derived.
Heat flux distribution and energy partition in creep-feed grinding
N.K. Kim, C. Guo, S. Malkin (1)  
STC G,  46/1/1997,  P.227
Keywords: grinding, temperature, energy partition
Abstract : This paper is concerned with the heat flux distribution and energy partition to the workpiece for creep-feed grinding. From measurements of transient grinding temperatures in the workpiece sub-surface using an embedded thermocouple, the overall energy partition was estimated from moving heat source theory as e ? 3.0%37; for down grinding and e ^? 4.5%37; for up grinding. An inverse heat transfer analysis was subsequently applied to calculate the heat flux and cooling distributions on the workpiece surface from the measured temperatures. Energy partition values from the inverse analysis were consistent with the results from moving heat source theory. The higher energy partition for up grinding may be attributed to thermal incompatibility at the grinding zone. Creep-feed down grinding should provide a more favorable thermal situation than up grinding.
An intelligent multi-agent approach for selection of grinding conditions
W.B. Rowe (1), Y. Li, X. Chen, B. Mills  
STC G,  46/1/1997,  P.233
Keywords: grinding, artificial intelligence, selection
Abstract : The advantages of a multi-agent approach are presented for the selection of grinding conditions. The agents consist of case based reasoning, neural network reasoning and rule based reasoning. Case based reasoning is employed as the main problem-solving agent to select combinations of the grinding wheel and values of control parameters. Rule based reasoning is employed where relevant data are not available in the case base. A neural network is employed to select a grinding wheel if required. The operator makes the final decision about the wheel or the values of control parameters. The multi-agent approach combines the strengths of the different agents employed, to generate hybrid solutions and overcomes the limitations of any single approach. A blackboard method was used as the means of integrating the multi-agent system. The system works as expected and demonstrates the potential of using artificial intelligence for selection of grinding conditions, as well as the capability to develop a powerful database by learning from experience.
The use of an efficient and intuitive tool for the dynamic modelling of grinding processes
J. Vinolas, J. Biera, J. Nieto, J.I. Llorente   / J. Vigneau (1)
STC G,  46/1/1997,  P.239
Keywords: modelling, grinding, chatter
Abstract : This paper presents, step-by-step, the capabilities that a general-purpose simulation environment, such as Simulink/Matlab, provides for an intuitive and efficient modelling of grinding processes. Starting from a revision of the different approaches which can be found in the technical literature the paper begins with the well-known block-diagram first presented by Snoeys. Next, the paper shows how this block-diagram is incorporated into the Simulink environment and how the different parameters for the simulation are introduced in the model (machine, grinding wheel and process parameters). Special attention is paid to the fact that nonlinear phenomena can easily be included.
Model based AE-monitoring of the grinding process
W. Hundt, F. Kuster, F. Rehsteiner (1)  
STC G,  46/1/1997,  P.243
Keywords: grinding, monitoring, model
Abstract : A kinematic model of single edge cutting action in grinding has been developed. The model describes the force pulse created by chip formation at the cutting edge. This pulse is assumed to excite acoustic emission (AE) signals. The typical values of its features (risetime, width, amplitude) determine the requirements for the measurement equipment. AE was measured on the workpiece during grinding and was analysed in the frequency range between 70 kHz and 3.5 MHz. A suitable signal analysis strategy was developed to extract meaningful information from the AE signal using frequency domain feature extraction. The comparison of model and measurement output allows the identification of model parameters. The parameter values give a description of the grinding wheel state and the process state.
High-precision surface grinding of ceramics with superfine grain diamond cup wheels
T. Matsuo (1), M. Touge, H. Yamada.  
STC G,  46/1/1997,  P.249
Keywords: grinding, ceramic, ductile transition
Abstract : High-precision surface grinding has been performed on the Si_3 N_4 , and AI_2 C_3 -TiC ceramics and Mn-Zn Ferrite using an ultra-precision surface grinder and very fine grain diamond cup wheels, where the maximum depth of cut was 2 µm and the maximum through feed rate being 100 mm/min. The surface roughness and percent brittle mode area were measured using an atomic force microscopy (AFM). These characteristics were discussed by a parameter "Smax" defined as Smax = µ a /v,/ v_s (µ : /successive cutting edge spacing, a : depth of cut, v, : through feed rate, v, : wheel speed). With decreasing grain size from #1200 to #16000, the surface roughness Rmax decreases to 20 to 30 nm. Similarly, a remarkable reduction in percent brittle mode area is seen by changing grain size. The effect of dressing stone on the ground surface was also investigated using 3D wheel surface topography.
Surface roughness generation mechanism of ultraprecision grinding of optical materials with a cup-typed resinoid-bonded diamond wheel
Y. Namba, M. Shiokawa, J. Yu   / N. Ikawa (1)
STC G,  46/1/1997,  P.253
Keywords: grinding, roughness, surface
Abstract : Super-smooth optical glass surfaces have been obtained by grinding using an ultraprecision surface grinder and a cup-type resinoid-bonded diamond wheel without any polishing. This paper deals with some mechanisms of surface roughness generation for brittle materials in ductile mode grinding. The shape of the contact area between a cup-type diamond wheel and sample in ultraprecision grinding has been measured with an optical profiler. The shape is affected by the grain size of the diamond powder, feed rate, and grinding time. Surface roughness can be estimated by a simple surface generation model where the inner edge angles of the wheel and feed rate determine the surface roughness in the ductile mode. The inner edge angles are affected by various grinding conditions.
Forces and specific energy in superfinishing of hardened steel
S.H. Chang, S. Balasubrahanya, S.Chandrasekar, T.N. Farris, F. Hashimoto   / M.C. Shaw (1)
STC G,  46/1/1997,  P.257
Keywords: superfinishing, force measurement, hardened steel
Abstract : A piezoelectric force transducer has been adapted and used to measure the forces acting on the abrasive stone during superfinishing of hardened steels. The sensor has a sufficiently high natural frequency and resolution to measure both the average and oscillatory forces to within 10 milli-Newton. By combining measurements of forces and material removal rates, specific energy and force ratio have been estimated. Several characteristics of the superfinishing process are shown to be well reflected in the force signature, and these are highlighted and explained in fundamental terms. The force transducer is shown to offer many possibilities for studying the mechanics of superfinishing in considerable detail.
Utilization of electrolyzing non-linearity in precision grinding with ELID (Electrolytic in-process dressing) for fabrication of hard material components
H. Ohmori, T. Nakagawa (1)  
STC G,  46/1/1997,  P.261
Keywords: grinding performance, in-process dressing, electrode oxidation
Abstract : Investigations were conducted on metallic wheel bond oxidation as the anode in ELID and non-linearity conditions to study electrolytic dressing characteristics and ELID-grinding performances by combining the three elements: 1)metallic wheel bond, 2)power supply, and 3)grinding fluid. The possibility of controlling non-linearity conditions when these three elements are combined was demonstrated. and each selected combination showed optimum performances in terms of efficiency, stability, accuracy, and grinding ratio. ELID was also successfully applied to coarse grit wheels. Several attempts to apply ELID rough grinding for the efficient and precision fabrication of structural components of hard materials such as ceramics and hard metals were also carried out.


A force controlled clamping element for intelligent fixturing
M.A. Mannan (2), J.P. Sollie  
STC M,  46/1/1997,  P.265
Keywords: force control, intelligent clamping, workpiece deformation
Abstract : This paper deals with the design of a force-controlled clamping element to be applied for intelligent fixturing with the aim to minimise workpiece deformation and distortion under a machining operation. An electro-mechanically controlled clamp is designed, fabricated and tested. Test results have shown that the designed, system is capable of controlling clamping force with an accuracy of +/- 1 N over the full range of 700 N with rather fast response time of 200 msec.
An open-architecture CNC CAD-CAM machining system with data-base sharing and mutual information feedback
M. Mitsuishi, T. Nagao (1), H. Okabe, M. Hashiguchi, K.Tanaka  
STC M,  46/1/1997,  P.269
Keywords: chatter, learning control, integrated computer aided manufacturing
Abstract : The authors have developed a highly efficient machining system which maintains a stable machining state through the use of multi-axis force information. The system has capabilities for cutting state monitoring, adaptive control and learning. This paper presents the following items based on our previous discussions: (a) implementation of machine tools with open-architecture CNCs, (b) efficient stability lobe acquisition methods as a practical data-base, and (c) data-base sharing methods among different machine tools. Experimental results showed the effectiveness of the proposed methods.
utonomously proficient CNC controller for high performance machine tools based on an open architecture concept
K. Yamazaki (2), Y. Hanaki, M. Mori, K. Tezuka  
STC M,  46/1/1997,  P.275
Keywords: intelligent CNC, open CNC, automatic machining
Abstract : The paper deals with the new controller for the high performance CNC machine tools. The controller proposed is referred to as "TRUE-CNC." "TRUE" means Transparent, Transportable and Transplantable, Revivable, User-reconfigurable, and Evolving. TRUE-CNC allows the operator to achieve the maximum productivity and highest possible quality of the machined parts in a given environment with autonomous capturing of the machining operation proficiency. The TRUE-CNC controller provides intelligent functions for less-skilled operator to run the high performance machine tools as if a skilled operator does. The concept and design aspects of the system architecture and the algorithms for functions developed for the TRUECNC are described in the paper.
Intelligent strategy of force and position parallel control for a robot
Y.H. Yin, J.Y. Zhu (1), Z.X. Wei  
STC M,  46/1/1997,  P.279
Keywords: robotics, intelligent force control, fuzzy neural network
Abstract : In the paper, an intelligent strategy of force and position parallel control is firstly and systematically presented based on intelligent theories such as large scale system, fuzzy theory and neural networks. The force control hierarchical system is built. Under the consideration of friction, the dynamic tangent and normal equations are determined. Fuzzy hierarchical coordination and neural parallel control are implemented. Some experimental research has been carried out on an Adept Three robot manipulator. The results prove that the intelligent strategy is effective and feasible.
Thermal behavior of industrial robots and possibilities for error compensation
U. Heisel (2), F. Richter, K.H. Wurst  
STC M,  46/1/1997,  P.283
Keywords: industrial robot, thermal displacement, compensation method
Abstract : The fundamental differences between the kinematics of SCARA-, six-axes- and portal robots as well as tripod and hexapod machines are also reflected in their varying thermal behaviour. This paper describes the sequential investigation of the thermal behaviour of industrial robots with a standardized experimental setup It includes a comparison of the results for the different robot types as well as conclusions regarding improvement possibilities in robot design. There are also suggestions for the compensation of errors due to thermal effects and for a correction of the spatial position of the tool center point (TCP).
Volumetric error analysis of a stewart platform based machine tool
A.J. Patel, K.F. Ehmann (2)  
STC M,  46/1/1997,  P.287
Keywords: error analysis, accuracy analysis, error sensitivity
Abstract : Striving for greater accuracy, some machine tool manufacturers are developing parallel structures for the next generation machine tool. Therefore, tools are needed to analyze the effect error sources have on this type of structure. A model of a Stewart Platform based machine tool is developed that provides the framework for inclusion of all relevant error sources. An error analysis is presented based on an error model formed through differentiation of the kinematic equations, and a sensitivity analysis is given as a design tool for tolerance allocation during manufacture. Finally, automated error analysis software is demonstrated that graphically depicts position and orientation errors along tool paths and throughout the workspace.
Systematic design of hexapods and other parallel link systems
G. Pritschow (1), K.-H. Wurst  
STC M,  46/1/1997,  P.291
Keywords: machines, design, hexapod
Abstract : During the last 30 years, a variety of different parallel kinematic links which are based on the known Stewart platform have been proposed and which are all inventive ideas. All existing machines. however. share the common characteristic that motion is generated either by length modification, positioning of the base points or by a combination of both. This contribution describes a systematic procedure for the design of parallel kinematic link mechanisms which comprises a great variety of possibilities.
Design and kinematics of a parallel manipulator for manufacturing
Q.Y. Wang, H. Zou, M.Y. Zhao, Q.M. Li   / H.W. Zheng (1)
STC M,  46/1/1997,  P.297
Keywords: parallel manipulator, mechanism design, kinematics analysis
Abstract : This paper presents a new model of parallel manipulator for manufacturing, whose mechanism comes from the general Stewart platform which has the advantages of high rigidity and high load capacity. A scheme of the link mechanism is also proposed to make the link structure very simple. The mechanism parameters are optimized by workspace analysis of the parallel mechanism. With the view of kinematics equivalence between parallel mechanism and serial mechanism, /by way /of hypothesis serial mechanism and branch hypothesis serial mechanism, an efficient kinematics algorithm has been developed. The problem, derived motion produced by the link structure, has also been solved conveniently.
Rigid XY theta table for ultraprecision machine tool driven by means of walking drive
E. Shamoto, T. Moriwaki (1)  
STC M,  46/1/1997,  P.301
Keywords: feed table, ultraprecision machine tool, piezoelectric actuator
Abstract : The present paper presents a new method to feed an XY table for ultraprecision machine tools by utilizing piezoelectric actuators, which is based on principle of Walking Drive. The table supported and driven by six pairs of the feed and support actuators. The device does not require any conventional guide methods, and the rigidity is high especially in the feed direction. A control algorithm is also proposed in the present research so that the feed velocity and direction can be controlled in real time. The simple control algorithm automatically generates the complicated voltage patterns to be applied to the actuators to generate any given motion. The present feed method for the XY table is expected to have various advantages for ultraprecision machine tools such as high positioning resolution, high rigidity, smooth motion and long stroke.
Application of electrorheological fluid dampers to machine tool elements
T. Aoyama, I. Inasaki (1)  
STC M,  46/1/1997,  P.309
Keywords: bearing, damping, improvement
Abstract : Electrorheological fluids (ERF) are colloidal suspension whose apparent viscosity is variable in response to the strength of an electric field. In this paper, the application of electrorheological fluids to machine tool elements is proposed. The dynamic characteristics of machine tool table systems with linear motion rolling element bearings are improved by using an ERF film damper. A high damping force can be induced by increasing the ERF viscosity when the table is being moved during machining and the viscosity can be reduced when the table is being moved rapidly so providing less viscous drag. The performance of the hydrostatic bearing can be controlled by using ERF instead of hydraulic oil. The bearing clearance and load carrying capacity can be controlled by adjusting the intensity of the applied electric field.
Construction of an integrated manufacturing system for 3-D micro structure - concept, design and realization -
Y. Hatamura (2), M. Nakao, T. Sato  
STC M,  46/1/1997,  P.313
Keywords: micro-manufacturing, micro-assembling, integrated system
Abstract : An integrated manufacturing system for 3D microstructures was conceptualized, designed, and actually built. The system realized 3D shaping using a fast atom beam etching under rotation of workpieces, and 3D assembly using a concentric manipulator under observation of a multi-view scanning electron microscope. Through its demonstration of 3D micro manufacturing, it was clarified : Knowledge about conventional machine manufacturing is useful even in micro-manufacturing : The knowledge could be applied under new functions of zero reaction force 3D shaping, constant monitoring and on-one-table operating : An image based control proved effective for the integrated micro-manufacturing systems.
Development of a high-performance deep-hole laser-guided tboring tool - guiding charasteristics -
A. Katsuki, H. Onikura, T. Sajima, M. Rikimaru   / H. Kudo (1)
STC M,  46/1/1997,  P.319
Keywords: boring, laser, adaptive control
Abstract : A laser- guided BTA tool using piezoelectric actuators was developed to prevent hole deviation. Three kinds of experiments were conducted to examine the performance of this tool using a duralumin workpiece with a prebored hole. The first experiment was performed to examine the conditions of the hole deviation in normal deep hole boring. The second was to examine whether the tool could go straight through without shifting toward a thin wall on one side of the workpiece. The third was to examine whether the tool could go straight through without advancing along an obliquely prebored hole. The results showed that the tool could be guided to go straight through despite the disturbances.
Milling simulation for process optimization in the field of die and mold manufacturing
K. Weinert (2), A. Enselmann, J. Friedhoff  
STC M,  46/1/1997,  P.325
Keywords: process optimisation, milling simolation, sculptured surfaces
Abstract : When milling sculptured surfaces the major problems are the limited precision due to milling-cutter deflections caused by the cutting force and a unsatisfactory process reliability. One method for improving surface quality while maintaining high process reliability is the computer-based engagement analysis and feed-rate adaptation. The aim of the feed-rate adaptation is to avoid intolerably high tool loads as they occur while semi-finishing sculptured surfaces. The method developed uses an efficient, volume model to simulate the cutting process. The calculation of the optimal feed-rate takes the main technological aspects of 3-axis milling into account. The efficiency of the approach developed is demonstrated with a practical example.
Manufacturing on demand in production networks
E. Westkämper (1)  
STC M,  46/1/1997,  P.329
Keywords: flexibility, manufacturing requirements planning (MRP), fractals
Abstract : In order to increase their competitiveness, companies optimize their production by outsourcing and integration of the most efficient suppliers. On the other hand, they try to fulfil specific requirements by extreme customer orientation and manufacturing on demand. This leads to new organizational procedures and manufacturing systems. Their characteristics are: autonomous manufacturing cells, fractal units, adaptive systems, dynamic and agile management, self-optimization and self-control, customer-specific order management, communication networks. Particularly "manufacturing on demand" and the order management in production networks require new methods. This paper deals with the management of networks with virtual elements and a new method for MRP which is based on the principles of dynamic integration between fractal units in production networks (agents) and includes learning methods for time and cost improvement.


Virtual manufacturing systems as advanced information infrastructure for integrating manufacturing resources and activities
K. Iwata (1), M. Onosato, K. Teramoto, S. Osaki  
STC O,  46/1/1997,  P.335
Keywords: visual, manufacturing, system, information, technology, integration
Abstract : Advanced information technology such as computer networking and 3D graphics is now forcing industrial companies to change their manufacturing systems to information-oriented ones. The authors propose an new approach to an advanced information infrastructure with manufacturing semantics by using virtual manufacturing systems. Virtual manufacturing systems have much potential to integrate manufacturing resources and activities distributed in computer networks. The paper also describes how virtual manufacturing systems will be applied to applications as the informational kernel with open architecture in advanced manufacturing systems.
The project management process in manufacturing systems engineering
U. Ekmark, J. Nelson/   / N. Martensson (1)
STC O,  46/1/1997,  P.339
Keywords: system, engineering, management
Abstract : Manufacturing systems engineering is characterized by increased technological complexity, requiring co-operation by many different experts. The management of this process is often carried out in an ad hoc manner, However, co-ordination is very important, and has a major influence on lead-time as well as quality of the resulting manufacturing system. This paper argues for conscious and a continuous improvement of the corporate knowledge and ability for managing multidisciplinary teams of specialists. Based on studies of a number of engineering projects a methodology is proposed, integrating management models and methods with those used within manufacturing systems engineering.
Modelling of biological manufacturing systems for dynamic reconfiguration
K. Ueda (2), J. Vaario, K.H. Ohkura  
STC O,  46/1/1997,  P.343
Keywords: manufacturing systems, dynamic environment, genetic information
Abstract : The concept of Biological Manufacturing Systems (BMS) aims at dealing with dynamic changes in external and internal environments in product life cycle from planning to disposal, based on biologically-inspired ideas such as self-growth, self-organization, adaptation and evolution. This paper describes modelling of BMS at a floor level and focuses on system reconfiguration. Computer simulation using the principle of self-organization shows that the proposed BMS model indicates adaptive behavior to the changes in products demands due to external environment and malfunction of manufacturing cells as an internal environment, and it provides the possibility of dynamic reconfiguration of manufacturing systems.
Virtual manufacturing system : a test-bed of engineering activities
K.I. Lee (2), S.D. Noh  
STC O,  46/1/1997,  P.347
Keywords: virtual, manufacturing, engineering, planning and control
Abstract : Virtual manufacturing system is an integrated computer based model which represents the physical and logical schema and the behavior of real manufacturing systems. In this paper, a prototype of a Virtual Manufacturing system is developed using an expert system shell and a database management system on Internet, and various manufacturing strategies are examined by it. Workflow modeling of a Virtual Manufacturing system is performed, and a manufacturing/product database is constructed. Also, Virtual factory and its functions for engineering activities including order processing, design, planning, scheduling, control and verification are implemented and integrated. Finally, real time scheduling using the multi-pass strategy, on-line process planning and production control system are applied. The experiences of this integration are satisfactory to propose the Virtual Manufacturing system as a good test-bed for diverse engineering activities in manufacturing.
Life-cycle-modelling as an instrument for life-cycle-engineering
R. Züst (2), G. Caduff   / B. Schumacher (1)
STC O,  46/1/1997,  P.351
Keywords: modelling, environmental impact, optimization
Abstract : Environmental impact is largely determined in the planning and development phases of a company's activities, products and services. This "planned" impact becomes visible later in the manufacture, use and disposal stages. In order to achieve an effective and efficient improvement in environmental performance, appropriate measures must thus be taken during the planning stage. A suitable instrument for early recognition of ecological and economic effects is, for example, modelling. In the following, two life cycle phases, both modelled during the course of research projects, are discussed.
An analytical method for integrating environmental & traditional design considerations
P. Jackson, D. Wallace   / R. Kegg (1)
STC O,  46/1/1997,  P.355
Keywords: integrated product design, environment, modelling
Abstract : Designing products for reduced environmental impact and improved performance requires that a diverse range of characteristics be considered. Such tradeoffs require a practicable method for combining specialized tools into an integrated analytical system. The paper describes how an integrated design tool can be constructed from modules which correspond to different aspects of the problem, such as geometry, materials and mathematical subproblems. An electronics housing design example (subject to electromagnetic, heat transfer, environmental and cost considerations) illustrates the use of the design methodology. The tool is then used to demonstrate the ability to investigate and understand interactions between different design goals.
Distributed simulation applied to production systems
H. Bley, C.C. Wuttke   / W. Massberg (1)
STC O,  46/1/1997,  P.361
Keywords: production systems, simulation, optimization
Abstract : To run nowadays production systems in an optimized way complex and time consuming models are helpful especially if an isolated analysis of subsystems is not possible. Operating problems like scheduling and resource requirement planning need short processing times while strategic problems lead to a large number of solutions to be evaluated. This paper proposes the problems to be solved and a modeling and simulation architecture that allows the use of distributed computer resources and databases. The approach of separated modeling and simulation allows a better performance. By a distinct example it is shown how this approach can be used for the optimization of storage using the eventdriven material flow simulation.
Agent-based control of self-organized production systems
H.-P. Wiendahl (1), V. Ahrens  
STC O,  46/1/1997,  P.365
Keywords: production control, scheduling, group technology
Abstract : The organization of production is getting more complex. This problem is today being tackled by dividing large systems in small ones and letting these act autonomously. Their mutual interdepencies, however, remain. This is why planning and controlling manufacturing systems will in the future be a matter of getting autonomous subsystems to co-operate voluntarily. We will suggest market rules. One approach used to this end is the agent theory. It is suitable as a modelling and simulation tool for research aims and as a basis for the construction of software tools which are able to support distributed manufacturing processes.
combined multicriteria approach for cellular manufacturing layout
M.H. Elwany, A.B. Khairy (2), M.G. Abou-Ali, N.A. Harraz  
STC O,  46/1/1997,  P.369
Keywords: layout, cellular, decision making
Abstract : In cellular manufacturing, the inter-cell layout phase is frequently affected by multiple qualitative and/or quantitative criteria. This paper presents a computer system developed to handle the two aspects individually or collectively. The system operates in tandem mode, combining a knowledge base with an improvement algorithm. The knowledge base generates a layout based on a set of rules, this layout is seeded optionally to an improvement Simulated Annealing global optimization algorithm to find a better configuration for the situation. The verification process is carried out by consulting the system a reasonable number of times using different boundary conditions. Results from consultations are included to illustrate the system's performance and capabilities.
A collaborative control system for mass customization manufacturing
M.M. Tseng, M. Lei, C.J. Su   / M.E. Merchant (1)
STC O,  46/1/1997,  P.373
Keywords: agile, co-operative scheduling, flexible manufacturing
Abstract : Mass Customization aims at producing customized products to meet individual customer's needs with mass production efficiency. The advent of this /new /mode of manufacturing introduces a different set of requirements on system control for manufacturing operations. The implications include the drastic increase of varieties, very small batch size, random arrival of orders, and wide spread of due dates. In addition, there are also factors such as similarity among tools, production plans and product designs. If properly utilized, that can help to reduce the complexities of the control systems. In order to develop a new type of control and coordination system to support mass customization, a heterogeneous coordination mechanism is developed. A price mechanism with the construct of intelligent agents in a market-like environment is investigated to fulfill the requirements.
A human factors framework for analysis of an assembly work
A. Kjellberg (2), L. Moestam  
STC O,  46/1/1997,  P.377
Keywords: human factors, learning, assembling
Abstract : Manual assembly work can be classified in terms of degrees of freedom. In car manufacturing "bounded work" means work at the moving assembly line. "Free work" is arranged in separate work stations for teams working with functional modules. The human factor characteristics of the different work types can be described by a three factor framework: Activation, Predictability and Freedom of Action. These three key factors are based on well-established and heavily researched theories. By analysing each, and their interdependence, with the different job assignments we have got a new qualitative description based on quantitative data. These data can be used for the balancing of process-oriented work rotation. work enlargement and work enrichment. With the use of this methodology a design of work tasks can be made that is both good for the individual worker and results in maximum utilisation of the total resources.
Development of the new human-conscious automobile assembly plant
A. Niimi, T. Sata (1), K. Shiramizu, T. Matsuura, N. Hisada  
STC O,  46/1/1997,  P.381
Keywords: assembling, load, man-machine system
Abstract : We developed an automobile assembly plant that places greater consideration on human beings. In order to achieve this, we reorganized work assignments based on vehicle function. Next, we improved worker satisfaction by enhancing the self-governing nature of work groups. Work loads were reduced by developing a method for quantifying physiological workloads of assembly jobs. Whenever automated equipment was introduced, we installed machines that work as team members with workers. Finally, we implemented various improvements in the overall work environment. As a result, we successfully designed a human-conscious plant with substantial improvements in productivity and quality.
Case based evaluation of potential deterioration for facility life-cycle management
S. Takata (2), H. Shiono, H. Hiraoka, H. Asama  
STC O,  46/1/1997,  P.385
Keywords: maintenance, deterioration, expert system
Abstract : Providing appropriate maintenance is essential to achieve effective production. For planning proper maintenance strategy, it is necessary to know potential deterioration of the facility which may lead to various problems. In this paper, we propose a case based approach to the evaluation of potential deterioration modes. Deterioration cases are represented in terms of the deterioration process in which basic deterioration mechanisms are combined. Algorithm for the qualitative evaluation of deterioration of the specified part of the facility is proposed. Propagation of effects of deterioration to other parts of the facility is also discussed. Effectiveness of the method is demonstrated using an experimental system.
A decision support system for ship maintenance capacity planning
R.J. de Boer, W.H.M. Zijm (2)  
STC O,  46/1/1997,  P.391
Keywords: maintenance, computer aided planning, scheduling
Abstract : In this paper. the basic framework and algorithms of a decision support system are discussed, which enhance process and capacity planning at a large repair shop. The research is strongly motivated by experiences in a project carried out at a dockyard, which performs repair, overhaul and modification programs for various classes of navy ships. We outline the basic requirements placed upon order acceptance, process planning and capacity scheduling for large maintenance projects. In subsequent sections a number of procedures and algorithms to deal with these requirements, in particular a procedure for workload-based capacity planning, a database system to support process planning are developed, as well as a resource-constrained project scheduling system to support work planning at a more detailed level. The system has been designed to support decision making at the Navy Dockyard in particular, however, we believe that, due to its generic structure, it is applicable to a wide range of project-based manufacturing and maintenance environments.
Near optimal scheduling of manufacturing systems with presence of batch machines, setup requirements
P.B. Luh, J.H. Wang, J.L. Wang, R.N. Tomastik, T.D. Howes (1)  
STC O,  46/1/1997,  P.397
Keywords: scheduling, batch processing, setup requirement
Abstract : Scheduling is a key factor for manufacturing productivity. Effective scheduling can improve on-time delivery, reduce inventory, cut lead time, and improve machine utilization. This study was motivated by the design and implementation of a scheduling system for a helicopter part production cell. The manufacturing is characterized by the presence of batch machines that can process multiple parts simultaneously, and the presence of machines requiring significant setup times. A novel mathematical optimization model with a separable structure is presented, and a solution methodology based on a combination of Lagrangian relaxation, dynamic programming, and heuristics is developed. Numerical results demonstrate that the method can generate near optimal schedules with quantifiable quality within a reasonable amount of computation time on a personal computer.
Reuse of control software for manufacturing systems
J.I. Llorente, M.I. Sarachaga, A. Burgos, J. Vinolas   / R. Bueno (1)
STC O,  46/1/1997,  P.403
Keywords: manufacturing system, software, control
Abstract : The paper here presented focuses on the application of software reuse to the development of manufacturing system control. It puts forward a methodology which includes the precise tools for the development, implementation and maintenance of such a kind of software. This methodology is the result of previous experiences and it combines two complementary methodologies: Synthesis and Reboot. The former places emphasis on the domain engineering, and the latter complements it thanks to its bottom-up approach to reuse, and the metrics for the software components. A practical implementation is also described, in which other software engineering concepts have been applied.
Interactive programmable feature recognisor
P. Gibson, H.S. Ismail, M. Sabin, K.K.B. Hon (2)  
STC O,  46/1/1997,  P.407
Keywords: feature, recognition, object-oriented programming
Abstract : This paper describes the structure and operation of a prototype feature recognition system programmed in the 'C++' language providing the user with the means of describing the required features interactively. The system was developed for use as both a Windows and a UNIX based application using a derivative of EXPRESS as the feature description language. At present the system can accept entity descriptions from CAD systems in the form of DXF files through a DXF translator. The paper provides a brief review of the current research in feature recognition and discusses the implementation of a set of methods for optimising the recognition process.
A method for tooling configuration in integrated manufacturing systems
T. Tolio, B. Colosimo, Q. Semeraro   / F. Jovane (1)
STC O,  46/1/1997,  P.411
Keywords: integrated, manufacturing, system, tooling, design, modelling
Abstract : Tooling configuration deeply affects the performance of Integrated Manufacturing Systems both in terms of flexibility and productivity. The literature on tooling configuration is extremely scarce and due to the lack of formal methods oversizing is a common practice which leads to high investments in tools. The paper presents a method for tooling configuration that is aimed at tool investment minimization under the constraint of a given system productivity. The method is applicable to real case situation involving hundreds of different tool types. The paper reports on the performance of the method under a set of cases based on a real system.
Integration of operator's experience into NC-manufacturing
H. Schulz (1), D. Spath (2)  
STC O,  46/1/1997,  P.415
Keywords: computer aided manufacturing (CAM), computer numerical control (CNC), manufacturing feature
Abstract : The existing program interface of numeric controls according to ISO 6983 (DIN 66025) has serious lacks regarding information volume and content, transparency and data exchange. Therefore, program adaptation can hardly be carried out down at the shop floor. Consequently, the manufacturing experience of the operator cannot be used. In order to solve this problem, a new manufacturing-feature-oriented method of description for drilling and milling processes has been developed. The machining job is described by manufacturing features, which represent the material volume that has to be removed. Each manufacturing feature is assigned to manufacturing steps, that contain necessary manufacturing parameters, e.g. way of method, tools, strategy and cutting parameters.
A verification program for 5-axis NC machining with general APT tools
M.C. Leu (2), L. Wang, D. Blackmore  
STC O,  46/1/1997,  P.419
Abstract :
Evolutionary design of fuzzy-logic controllers for manufacturing systems
B. Porter, N.N. Zadeh   / A. Chisholm (1)
STC O,  46/1/1997,  P.425
Keywords: automation, fuzzy logic, production control
Abstract : In industrial automation, fuzzy-logic controllers can be used to minimise work-in-progress, production surplus, and production backlog. The methodology presented it this paper for the design of such controllers for manufacturing systems involves the use of evolution strategies rather than genet c algorithms. This evolutionary procedure is illustrated by designing a fuzzy-logic controller for a non-reentrant manufacturing system incorporating two machines and producing a single part-type. It is indicated that, in this case, the evolutionary design procedure is approximately ten times faster than that involved in the analogous genetic design procedure.
Determination of optimal parting directions in plastic injection mold design
A.Y.C. Nee (1), M.W. Fu, J.Y.H. Fuh, K.S. Lee, Y.F. Zhang  
STC O,  46/1/1997,  P.429
Keywords: injection, molding, CAD
Abstract : Automatic recognition and extraction of undercut features is e bottleneck in computer-aided injection mold design. The number of undercuts and their locations affect the parting directions and surfaces, side-core mechanism, sliders and lifters design, and the overall structure of a mold. In this paper, a methodology is proposed for the recognition and extraction of undercuts based on their geometrical characteristics and topological relationships of the molded parts. With the developed software, undercuts can be classified and recognized automatically from a 3-D model of a molded part. In order to define the undercut criteria clearly, a new classification method is presented. Since most of the injection molded parts consist of curved surfaces and free-formed surfaces, recognition and extraction of these surfaces are also introduced. After all the undercuts are extracted, the optimal parting direction is chosen based on the proposed criterion of considering the number of possible undercuts and their corresponding undercut volumes. From the case studies on several industrial parts, the methodology developed is found to be efficient in determining the optimal parting direction of injection molded parts.
Feedrate optimization of ball end milling considering local shape features
C.N. Chu (2), S.Y. Kim, B.H. Kim, J.M. Lee (1)  
STC O,  46/1/1997,  P.433
Keywords: code, feature, feed
Abstract : In ball end milling of free form surfaces, static and dynamic cutting characteristics change dramatically for different local shape features. Local shape features are classified as plain, upward ramp, downward ramp, contour, convex corner and concave corner. Data base for stable cutting conditions of zinc base alloy was established through various experiments with different local shape features. Feed rate optimization program, Opticode, was developed from the relationship between optimal feed rate and local shape feature. In Opticode, local features are recognized by comparing NC codes of neighboring points. The developed program was applied to automobile prototype production dies.


Twin-probe vibroscanning method for dimensional measurement of microholes
T. Masuzawa (1), B.J. Kim, C. Bergaud, M. Fujino  
STC P,  46/1/1997,  P.437
Keywords: measurement, dimension, microhole
Abstract : We present a new twin-probe vibroscanning method for measuring the inside profile of microholes in electrically nonconductive materials. Instead of the single cantilever probe used in the conventional vibroscanning method, a probe with two elements in electrical contact is used to detect the surface. Following a feasibility test with a macroscale prototype device, the measurement of microholes was realized using a silicon-based microprobe.
A multi-point method for spindle error motion measurement
G.X. Zhang (1), Y.H. Zhang, S.M. Yang, Z. Li.  
STC P,  46/1/1997,  P.441
Keywords: measurement, spindle error, multi-point method
Abstract : A multi-point method for spindle error motion measurement is proposed in the paper. The radial error motion of the spindle is measured by 4 probes, where as the axial and tilt ones by 5 probes. Roundness error and flatness error of the specimens used for measuring the spindle error motions are separated and have little effect on the accuracy of spindle error motion measurement. For assuring high accuracy of measurements techniques for determining the actual angular positions of the probes and hardware of measuring system have been also developed. The proposed method can be used for real-time spindle error motion measurement with sub-micron accuracy.
Linear-motor-levitated stage for photolithography
W.J. Kim, D.L. Trumper   / J.B. Bryan (1)
STC P,  46/1/1997,  P.447
Keywords: mechatronic, precision, actuator
Abstract : This paper presents a linear-motor-levitated stage with large planar motion capability. This positioning system is the first capable of providing all the motions required for photolithography in semiconductor manufacturing with only a single moving part. The single moving part generates all six-degree-of-freedom (6-DOF) motions required for focusing and alignment, and large two-dimensional motions (50 ^ * 50 mm) for positioning. Four linear permanent-magnet motors produce suspension forces to support the moving part (5.58 kg) as well as driving forces. The stage is to have tens-of-nanometer position stability and the design can be readily scaled to accommodate 12-inch wafers in the next generation of photolithography. The prototype stage is being levitated in initial testing.
Ductile regime cutting of brittle materials using a flying tool under negative pressure
Y. Kamimura, H. Yamaguchi, Y. Tani (2)  
STC P,  46/1/1997,  P.451
Keywords: precision cutting, ductile transition, brittle materials
Abstract : The importance of ductile regime cutting has been emphasized in the production of large-diameter optics and semiconductor substrates over the last ten years. However the available technology has not yet been implemented in industry. The reason is that cutting technology based on the motion-copying principle is too sensitive for error motions of a machine tool to maintain the actual depth of cut stably below the critical depth. A new cutting technology using a flying tool under negative pressure has been developed. In this technology, a flying tool glides over a workpiece surface while maintaining a small height like a negative-pressure slider of a magnetic disc drive. Using the tool system, ductile regime cutting of optical glass and monocrystalline silicon was examined, and a mirror-surface finish with no cracks was achieved on a face lathe having a 0.1 p m order of error motion.
Micromachined thin film mirror array for reflective light modulation
S.G. Kim (2), K.H. Hwang, Y.J. Choi, Y.K. Min, J.M. Bae  
STC P,  46/1/1997,  P.455
Keywords: micromachining, mirror, piezoelectricity
Abstract : Actuated Mirror Array (AMA) is a new reflective type light modulator that uses micromachined thin film piezoelectric actuators in conjunction with 300.000 micro mirrors of 100 ?m by 100 ?m size. A mirror array module consists of the active matrix, where the image signal voltages are applied, and the cantilever beams, which are actuated by the applied signal voltages, on top of the active matrix. Since the tilting of the mirror pixel defines the gray scale or the light beam on the screen, the 300.000 mirror pixels should have initial positions as uniform as possible. A novel support anchor design for the micromachined cantilever beams is developed to provide uniform initial deflection of the cantilever. By implementing a secondary support to the anchor of the cantilever beam, the initial deflection can be reduced to 35%37;.
Stitching interferometry for the measurement of aspheric surfaces
Y.J. Fan, K.G. Struik, P.C. Mulders (2), C.H.F. Velzel  
STC P,  46/1/1997,  P.459
Keywords: interferometry, aspheric optical surface, measurement
Abstract : In this paper, we describe the progress being made in the development of stitching interferometry for measuring curved surfaces with large aspheric departures. Stitching interferometry is an extension of conventional interferometry by making a series of submeasurements and then stitching the surface segments together to obtain an entire reconstructed surface. We have implemented it by modifying a phase shifting interferometer with a mechanical manipulator for shifting and/or rotating the workpieces under test precisely. An outline summarising the principles and the algorithms developed, to correct the aberrations introduced by the misalignment of the submeasurements and the misregistration of the individual data sets, is presented. The technique offers considerable potential applications for testing precision surfaces with large aspheric departures.
Results of the CIRP-Euromet intercomparison of ball plate-based techniques for determining CMM parametric errors
Vanherck (1),A. Balsamo (2), M. Franke, E. Trapet, F. Wäldele, L. De Jonge, P  
STC P,  46/1/1997,  P.463
Keywords: co-operative project, coordinate measuring machine (CMM), software error compensation
Abstract : The general scheme and the results of the intercomparison are presented. The techniques compared are reviewed and the advantages of using ball plates to determine CMM parametric errors are illustrated. The experimental procedures as well as the data reductions are covered by the comparison. The results show the potential of the compared techniques. and that they are essentially equivalent in their capabilities of predicting and compensating for CMM geometrical errors. Improvements in the scheme are recommended for future intercomparisons and extensions to other participants.
A combined optical and mechanical reference artefact for coordinate measuring machines
H.N. Hansen, L. De Chiffre (2)  
STC P,  46/1/1997,  P.467
Keywords: coordinate measuring machine (CMM), optical probe, calibration
Abstract : The calibration of CMMs using calibrated ball plates or hole plates is a well established technique. In the case of CMMs equipped with optical sensors based upon CCD cameras a series of artefacts based upon chromium-on-glass structures have been proposed. Calibration of these artefacts can not be performed using the reversal method which can be used for ball or hole plates. A new two-dimensional artefact based upon mechanical elements has been developed allowing both optical and mechanical probing and calibration. This artefact combines in one piece the possibilities of performance verification of both optical and mechanical CMMs. The mechanical elements have been manufactured with form errors less than 3 pm and using a special surface preparation that makes optical CNC-measurements non-problematic. Reproducibilities better than 0.5 pm have been obtained in optical probing. Calibration of the artefact can be carried out using reversal methods using both optical and mechanical probing.
Part form errors predicted from machine tool performance measurements
R.G. Wilhelm, N. Srinivasan, F. Farabaugh   / R. Hocken (1)
STC P,  46/1/1997,  P.471
Keywords: machining, metrology, tolerancing
Abstract : Machine tool performance testing, as defined by ISC 230 and ANSI B5,54. has been successfully used to maintain and improve the accuracy and repeatability of production-level machine tools. In this study, a controlled series of experiments have been used to test the efficacy of these performance tests in the prediction of part form errors. Results are shown for flatness, squareness. position. and profile tolerances. The experimental results suggest that standard machine tool performance tests can also be used to predict the "best-case" tolerances that can be achieved for particular part features.
Swept envelopes of cutting tools in integrated machine and workpiece error budgeting
D. Frey, K. Otto, W. Pflager   / R. Donaldson (1)
STC P,  46/1/1997,  P.475
Keywords: error budgeting, geometric modeling, machining
Abstract : This paper presents closed form equations for calculating discrete points on the surface of a machined part given the shape and the motion function of the cutting tool. This permits rapid calculation of the effect of machine tool geometric errors on the shape of the machined part. A valve grinding machine serves as an example application of the equations. The proper profile of the grinding wheel is derived based on the desired profile of the valve. The model is also used to estimate acceptable magnitudes of errors in the machine based on desired par; tolerances.
Development of a traceable laser based displacement calibration system with nanometer accuracy
S.F.C.L. Wetzels, P.H.J. Schellekens (2)  
STC P,  46/1/1997,  P.481
Keywords: displacement calibration, laser measuring instrument
Abstract : High precision sensors become increasingly sensitive due to the use of advanced measuring principles and construction techniques. Traceable accuracy though can only be achieved via calibration. Based on a Fabry-Perot interferometer we have developed a calibration set-up for high precision displacement sensors that allows calibrations over a range of 300 um with an uncertainty of about 0.5 nm. The resolution is smaller than 0.1 nm. The resonance frequency of the Fabry-Perot cavity is tracked by a slave laser. Its frequency is measured against a standard laser. By using the well known relation between the resonance frequency and the displacement of the cavity mirror the frequency data can be compared with the readout of the sensor which is connected to the moving mirror. By locking the slave laser to successive resonances of the cavity the calibration range is not limited by the tuning range of the laser.


Subsurface lattice disorder in polished II-VI semiconductors
D.A. Lucca (2), C.J. Maggiore  
STC S,  46/1/1997,  P.485
Keywords: surface, polishing, subsurface damage
Abstract : The near surface lattice disorder created by polishing of II-VI semiconductors has been examined. Ion channeling was used to quantify the subsurface damage in single crystal (0001) oriented CdS and (100) oriented ZnSe. Surfaces prepared by both mechanical and chemo-mechanical polishing were examined. Both total amount of lattice disorder and damage depth were found to be significantly higher for ZnSe when compared to CdS. Investigation of the presence of damage beyond that identified by the backscattered surface peak for the mechanical polished ZnSe surfaces was made by study of the rate of dechanneling with depth below the surface.
Surface integrity of AlSi9 machined with PCD cutting tool
G. Byrne (1), J. Barry, p. Young  
STC S,  46/1/1997,  P.489
Keywords: surface integrity, machining
Abstract : Economic and environmental pressures have lead to the need to replace manufacturing processes characterised by the use of undefined cutting edges with those which use a defined cutting edge (e.g. replace honing with boring). Fundamental to the achievement of this goal is the ability to generate the surface integrity characteristics of current undefined cutting edge finishing operations using single point machining processes. In this paper, the surface integrity of an Aluminium Silicon Alloy, AlSi9, whose surface has been generated by external cylindrical turning under dry cutting conditions with Polycrystalline Diamond cutting tools is examined. For a range of cutting speeds, feeds and depths cf cut, measurements of cutting force, topography of the machined surface micro-hardness and work hardening backed up with optical/electron microscopy were undertaken, Good replication of the tool profile on the machined surface was found to exist, with no evidence of work-hardening. The main surface defect observed was small craters or pits, and these have been directly associated with the microstructure of the alloy.
Influence of processing conditions and reinforcement on the surface quality of finish machined aluminium alloy matrix composites
H. Chandrasekaran (2), J.O. Johansson  
STC S,  46/1/1997,  P.493
Keywords: grinding, surface, composites
Abstract : Fibre/particle reinforced aluminium alloy matrix composites appear to have a good future as candidate material for engineering components. However, their machinability is poor and surface quality is not established. The influence of finishing operation (mainly grinding) upon the surface quality of some experimental aluminium alloy matrix composite materials manufactured by different methods was systematically investigated. These materials contained different type, size and amount of hard reinforcements. Surface quality was evaluated and the relative influence of processing and reinforcement was mapped using profilometry and scanning electron microscopy (SEM). In most instances surface damage in terms of particle/fibre pull out and cavity formation, detrimental in applications involving friction and corrosion, was observed.
A comparison of topographic characterization parameters in grinding
A.J. Terry, C.A. Brown (2)  
STC S,  46/1/1997,  P.497
Keywords: surface roughness, statistical test, grinding
Abstract : Parameters for characterizing topographies and a method of selecting these parameters are investigated. Conventional and scale-sensitive fractal parameters are tested for cross-correlations, ability to differentiate process variables and ability to relate grinding wheel topography with ground surface topography. Surfaces were ground using different wheels, dress leads and removal rates. Profiles were acquired by contact stylus profiling parallel and perpendicular to the grinding direction on the grinding wheels and the ground surfaces. The conventional height parameters tend to be more cross-correlated than the spacing and fractal parameters. No parameters in this study could differentiate the process variables or could relate wheel and workpiece topographies in all situations. The waviness height (Wt; was the best for differentiating process variables, and a scale-sensitive fractal-based parameter, the smooth-rough crossover (SRC), was best at relating workpiece and wheel topographies.
A new speckle-interferometric approach to measure the 3D-shape-measurement of discontinuous free form surfaces
T. Pfeifer (2), J. Evertz, H. Mischo  
STC S,  46/1/1997,  P.501
Keywords: metrology, optical measurement technique, optical measuring instrument
Abstract : In Electronic Speckle Pattern Interferometry (ESPI) the introduction of sc-called translation and multiple-wavelength-techniques enable the user to collect data relating to a 3D-topography within a short space of time. While smooth surfaces may be measured using standard approaches, the investigation of shapes with discontinuities demands more advanced techniques. Various methods have been studied at the IPT. Our results demonstrate that by transfering the concept of Coded Light Sectioning to an ESPI translation-technique in a generalised form, a wide variety of free forms, particularly those with large discontinuities can be measured with high levels of resolution and accuracy. The paper describes this new approach and presents various examples of current applications.
On mirror surfaces obtained with and without polishing
V.C. Venkatesh (1), F. Fang, W.K. Chee  
STC S,  46/1/1997,  P.505
Keywords: mirror surfaces, scratching, ultra-precision machining
Abstract : Mirror surfaces were created by turning and/or grinding various materials: silicon, glass (pyrex and BK7), aluminum & Si alloy, and zinc selenide, some unpolished and others polished. The mirror surfaces were assessed by two novel techniques, one by measuring lightness (a measure of their reflectivity), and the other by scratching with a coni-cylinderical diamond (fully, symmetrical), as against the traditional Vickers diamond indentor that has two alternate cutting edges (face or wedge). By using an AFM to section the scratch, the pile up (double or single) was observed and SEM confirmed the nature of the scratch whether it was ductile or brittle. Results show that polishing improves the mirror surface however good the initial surface may be.