Precision Engineering & Optomechanics

84, S. Asai, A. Kobayashi, "Observations of Chip Producing Behavior in Ultra-Precision Diamond Machining and Study on Mirror-Like Surface Generating Mechanism," Precision Engineering, 12(3), pp. 137-143. (July 1990). The behavior of ultra-precision diamond machining behavior and the sharpness of the diamond tool edge were monitored by cutting noise measurements, the chips were observed with a scanning electron microscope (SEM) and the machined surface observed with an interference microscope. As a result, it was concluded that a mirror surface is generated at a machined section depth which is smaller than the cutting edge radius of the tool. Hence, it is very important to pay close attention to the chip producing behavior. The shear angle was not maintained throughout the chip, as two different shear angles, 14 and 17 deg , were observed. These values were dependent on the value of the undeformed chip thickness compared with the cutting edge radius. Even during micro-infeed ultraprecision diamond machining, the surface temperature of the chips during machining was assumed to be rather high, exceeding the melting temperature ( approx 660 deg C) for A1 alloys. Workpiece materials included pure A1, A1--Mg--Si alloy and AI--0.2Fe alloy. Photomicrographs. 11 ref. 85, B. A. Kravchenko, " O n the Influence of Machining Parameters on the Forces Acting on the Back Rake Surface of the Tool," Soviet Engineering Research, 9(6), pp. 56-60. (1989). Information about the forces acting on the surfaces of a cutting tool is not only of cognitive, theoretical importance, but is also, and not to a lesser degree, of practical value. In particular, the magnitude and distribution of forces on the back of rake surface of a sharp tool exert influence on its wear, as well as on formation of the surface layer of the blank (strain hardening, residual stresses). Determination of the forces in the cutting zone is connected with certain difficulties. This paper presents a method for calculating the coefficients of friction on the top cutting surface and the forces acting on the back rake surface of the tool. 4 Refs. 86, P. Mutschler, " O p e n Communication in Machine-tools," Werkstatt und Betrieb, pp. 777-80. (Oct. 1990). Several manufacturers of machine tools, drives and numeric controls (NC) are working together on a proposal for standardization of a real time communication system that covers the specific requirements of a machine tool in a technically and economically optimal way. All information between the NC and the drives will be exchanged via a plastic fibre optical ring. A time slot assignment guarantees collision-free deterministic access to the ring. Since the digital communication system is part of high speed closed control loops (position control), several synchronizations are to be introduced to join data transmission and data processing in the NC and in the drives. The application-specific content of the exchanged messages can be rearranged each time the ring is initialized. (German). 87, M. J. Lacombat, S. Wittekoek, "Optical Microlithography & Metrology for Microcircuit Fabrication," Vol 1138, (Society of Photo-Optical Instrumentation Engineers, Bellingham, WA (USA), 1989). 206 pages. $56.00 88, T. Pfeifer, J. Elzer, "Optoelectronic Drill Wear Monitoring. From the Laboratory into the Workshop," VDIZ, pp. 193-4, 197-8. (Oct. 1990). In the process of automating production engineering, it is important to consider the monitoring of cutting operations, as a cost-efficient utilization of production systems is possible only if down times are avoided. Frequent causes for operational interruptions are tool breakage and tool wear. In-process wear monitoring can avoid tool breakages and so minimize interruptions in the process. The paper presents a monitoring system capable of detecting wear of spiral drills automatically. It is applied to a CNC machining centre. The wear measuring system operates a CCD camera and a PC-based image processing. (German) 89, F. J. A. van Houten, A. H. Van't Erve, "PART; a Parallel Approach to Computer Aided Process Planning," Fourth International Conference on Computer-Aided Production Engineering, Edinburgh, UK, Nov. 1988. pp. 281-8 558. Mech. Eng. Publications. Bury St. Edmunds, UK. This paper describes the architecture and functional design specifications of PART, a generative computer-aided process and operations planning system, currently under development at the University of Twente, PART covers the major process and operations planning functions for machining operations on CNC lathes and machining centers; from interpretation of the product model to NC tape generation. The system uses both algorithmic and AI-based techniques for automatic decision-making. PART is implemented as a set of cooperating processes which can be executed in parallel, even on different CPUs across a network. This system design allows easy customization via adaptation of planning scenarios. 90, A. K. Elshennawy, I. Ham, "Performance

Improvement in Coordinate Measuring Machines by Error Compensation," Journal of Manufacturing Systems, pp. 151-8. (1990). Describes the development and application of an error compensation technique for improving the performance of coordinate measuring machines. This procedure requires a complete calibration of the machine and a development of its kinematic model. When applied to a coordinate measuring machine, the technique improved machine performance by an average factor of four. The proposed method considers only geometric positioning errors and can be applied in situations where thermal effects can be safely ignored. 91, W. Kesternich, K. Eckert, "Precision Cutting Tool for TEM-Samples and Its Application," P r a k t i s c h e Metallographie, 27(6), pp. 301-304. (June 1990). The sample cutter's outstanding characteristics include a functionally wellthought-out construction and a mechanically precise finishing process, which result in the production of very smooth cuts. The high performance of this instrument has been demonstrated on radioactive and ferromagnetic materials, where microdiscs of 1 mm diameter were cut from previously electrolytically thinned samples without any significant damage to the electron transparent samples areas. Photomicrographs. (English and German). 92, D. E. Vukobratovich, "Precision Engineering & Optomechanics," (SPIE, 1989). 403 pages. $56.00 93, W. Warziniak, A. Koch, H. M. Kawalec, T. Kloczkowski, "Precision Turning With Straight Cutting Edges of Rotary Cutting Plates," Feingeratetechnik, 39(3), pp. 107-109. (Mar. 1990). Theoretical and practical studies of relationships between tool properties (contact area, cutting edge, etc.) and machining results on steel C60, GGL 25, A1Mg5 and CuZn40Pb2 (brass), respectively, are reported. A new turning tool has been developed which extends the potential for precision or final machining of cylindrical and spherical outer surfaces. Principles are explained. Graphs. 9 ref. (German)

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