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Flexibility and Measuring Accuracy with Optical Measuring Centres
40, A. Russel, "Fine G r i n d i n g - A Review," Keramische Zeitschrift, 42(5), (May 1990). A comprehensive review of fine grinding variants in machine construction is given. Both extensive areas of attrition mills and of jet mills are discussed especially with respect to the available types of mills. Large scale milling (roller mills and roller presses as well as tower mills) are likewise enumerated. After describing the available grinding aids (dispersing agents etc.), some attention is paid to markets and a look is taken at future processing methods. (German) 41, X. Cal, M. Adamiker, A. Wagendristel, H. Bangert, P. Torzicky, "Finite Element Study of the Penetration of an Indenter into Coated Systems," Vacuum, 40(1-2), pp. 232-233. (1990). The interplay of stress and strain and the load distribution along the contact area between indenter and the tested body are calculated for a coated system, Such a non linear etastoplastic deformation process can be treated theoretically only by numerical means. This was performed by a very effective finite element program. Different two dimensional approaches to the common Vickers microhardness test geometry will be presented: wedge and cone shaped indenters lead either to the uniaxial or the axial symmetric strain distribution. It is shown that friction forces between indenter and deformed material are not significant for obtuse-angled indenters. There is practically no relative movement along the contact interface and the deformation process is mainly characterized by embossed imprinting: No cutting of the material occurs even in thin films provided the indentation depth does not exceed film thickness too much. Load vs imprint depth diagrams for indentation and during subsequent load reduction are also presented and show the gradual take over of the test load by the substrate after the film is penetrated. They also show the influence of elastic re-deformation. The reliability of computed results is justified by their agreement with wedge hardness measurements on steel and gold solid samples. Proceedings of the Yugoslav-Austrian-Hungarian Fourth Joint Vacuum Conference 42, R. Aini, H. Rahnejat, R. Gohar, "Five Degrees of Freedom Analysis of V i b r a t i o n s in Precision Spindles,"
International Journal of Machine Tools & Manufacture, 30(1 ), pp. l - t 8. (1990). This paper outlines a five degrees of freedom model of a rigid shaft supported by a pair of angular contact ball bearings. The model simulates an existing precision grinding machine tool spindle. It enables the study of various loading arrangements to be carried out. 18 Refs. 43, H. Hermle, R. Goebel, "Flexibility and Measuring Accuracy with Optical Measuring Centres," Werkstatt und Betrieb, 123(7), pp. ZM153-ZM155. (Jul 1990). The efforts not only to measure production quality, but to actually produce it led a manufacturer of machine tools and laboratory equipment to new thoughts about rational quality assurance. The supply of precision machining technology for the automobile industry, aerospace industry, as well as the fine engineering and optical industry also had to be taken into account. (German) 44, S. Mochida, K. Kubo, H. Nagano, S. Kubota, K. Matsumura, S. Ueda, "Flexible M a n u f a c t u r i n g System for Aspherical Glass Lenses," National Technical Report (Matsushita Electric Industry Company), 36(2), pp. 32-40. (Apr 1990). Aspherical lenses are employed increasingly these days in optics-applied products, such as AV equipment and OA equipment. In order to popularize aspherical lenses, it is important to produce them in quantity at low cost. In response to this requirement, a flexible manufacturing system for aspherical glass lenses by a grinding and polishing method has been develope d which is suitable for producing small quantity of multitype products. This system is equipped with an ultrahigh-accuracy NC grinding machine which has two diamond wheels by means of straightness error compensation of six axes, and with a precision polishing machine by means of an elastic polisher. The system has an aspherical accuracy of 0.2 I.tm, and a finished roughness of Rmax 0.01 ~tm. This paper describes the aspherical lens producing method and the mass fabrication process. Also described are various processing methods and the examples of the applications of aspherical lenses to optical systems. 15 Refs. (Japanese) 45, P. A. S. Ralston, T. L. Ward, "Fuzzy Logic Control of Machining," Manufacturing Review, 3(3), pp. 147-154. (Sep 1990). Fuzzy control theory has progressed from the founding concept by Zadeh in 1965, to application to industrial control by Mamdani in 1977, and is now being combined with artificial intelligence techniques. General purpose fuzzy controllers and fuzzy logic LSI chips are available. This paper introduces the subject of fuzzy logic control (FLC) and provides a comprehensive literature survey of applications. The design and implementation of a FLC controller is described followed by a critical review of the FLC of machining. 94 Refs. 46, S. Chandrasekar, T. N. Farris, B. Bhushan, "Grinding Temperatures for Magnetic Ceramics and Steel," Journal oj Tribology (Transactions of the ASME), 112(3), pp. 535-541. (July 1990). Grinding temperatures are measured using an infrared sensor in ferrite and steel. For reference purposes, temperatures are also measured in a reduced model for grinding which consists of a single diamond grain sliding across the workpiece surface at high speed. The results include temperature as a function of sliding velocity, rate of temperature decay as the grain moves away from contact, and histograms of the frequency that grains on the grinding wheel attain a given temperature. It is found that temperature measurements can be used to detect out-of'roundness in the wheel. Finally, a simplified two-dimensional model based on a heat flux moving with constant velocity gives reasonably good agreement with experiment. Graphs, Photomicrographs. 31 ref. 47, M. Albert, "High Performance EDM," Modern Machine Shop, 62(t 1), pp. 67-73. (Apt 1990). With great accuracy and fine surface finish at vastly higher cutting speeds, wire EDM is headed in entirely new directions. A job shop near Chicago is pointing the way. This job shop routinely cuts two or three times faster than most shops using standard wire EDM units, even those with the latest generation of equipment. And it does so without compromising accuracy or surface finish. 48, P. Merkel, "High Speed Lathe," lnd.-Anz., 112(21), pp. 48-50. (13 Mar 1990). A research project assignment resulted in the development of high speed lathe machining methods. The advantages of the new method include the machining of difficult materials (e.g. A1), high surface quality and a major reduction, up to 85%, in the required operation time. The equipment is CNC operated and uses a high speed central processing unit. The achievable precision is not compromised by the increased machining speed. (German).
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International Journal of Machine Tools & Manufacture, 30(1 ), pp. l - t 8. (1990). This paper outlines a five degrees of freedom model of a rigid shaft supported by a pair of angular contact ball bearings. The model simulates an existing precision grinding machine tool spindle. It enables the study of various loading arrangements to be carried out. 18 Refs. 43, H. Hermle, R. Goebel, "Flexibility and Measuring Accuracy with Optical Measuring Centres," Werkstatt und Betrieb, 123(7), pp. ZM153-ZM155. (Jul 1990). The efforts not only to measure production quality, but to actually produce it led a manufacturer of machine tools and laboratory equipment to new thoughts about rational quality assurance. The supply of precision machining technology for the automobile industry, aerospace industry, as well as the fine engineering and optical industry also had to be taken into account. (German) 44, S. Mochida, K. Kubo, H. Nagano, S. Kubota, K. Matsumura, S. Ueda, "Flexible M a n u f a c t u r i n g System for Aspherical Glass Lenses," National Technical Report (Matsushita Electric Industry Company), 36(2), pp. 32-40. (Apr 1990). Aspherical lenses are employed increasingly these days in optics-applied products, such as AV equipment and OA equipment. In order to popularize aspherical lenses, it is important to produce them in quantity at low cost. In response to this requirement, a flexible manufacturing system for aspherical glass lenses by a grinding and polishing method has been develope d which is suitable for producing small quantity of multitype products. This system is equipped with an ultrahigh-accuracy NC grinding machine which has two diamond wheels by means of straightness error compensation of six axes, and with a precision polishing machine by means of an elastic polisher. The system has an aspherical accuracy of 0.2 I.tm, and a finished roughness of Rmax 0.01 ~tm. This paper describes the aspherical lens producing method and the mass fabrication process. Also described are various processing methods and the examples of the applications of aspherical lenses to optical systems. 15 Refs. (Japanese) 45, P. A. S. Ralston, T. L. Ward, "Fuzzy Logic Control of Machining," Manufacturing Review, 3(3), pp. 147-154. (Sep 1990). Fuzzy control theory has progressed from the founding concept by Zadeh in 1965, to application to industrial control by Mamdani in 1977, and is now being combined with artificial intelligence techniques. General purpose fuzzy controllers and fuzzy logic LSI chips are available. This paper introduces the subject of fuzzy logic control (FLC) and provides a comprehensive literature survey of applications. The design and implementation of a FLC controller is described followed by a critical review of the FLC of machining. 94 Refs. 46, S. Chandrasekar, T. N. Farris, B. Bhushan, "Grinding Temperatures for Magnetic Ceramics and Steel," Journal oj Tribology (Transactions of the ASME), 112(3), pp. 535-541. (July 1990). Grinding temperatures are measured using an infrared sensor in ferrite and steel. For reference purposes, temperatures are also measured in a reduced model for grinding which consists of a single diamond grain sliding across the workpiece surface at high speed. The results include temperature as a function of sliding velocity, rate of temperature decay as the grain moves away from contact, and histograms of the frequency that grains on the grinding wheel attain a given temperature. It is found that temperature measurements can be used to detect out-of'roundness in the wheel. Finally, a simplified two-dimensional model based on a heat flux moving with constant velocity gives reasonably good agreement with experiment. Graphs, Photomicrographs. 31 ref. 47, M. Albert, "High Performance EDM," Modern Machine Shop, 62(t 1), pp. 67-73. (Apt 1990). With great accuracy and fine surface finish at vastly higher cutting speeds, wire EDM is headed in entirely new directions. A job shop near Chicago is pointing the way. This job shop routinely cuts two or three times faster than most shops using standard wire EDM units, even those with the latest generation of equipment. And it does so without compromising accuracy or surface finish. 48, P. Merkel, "High Speed Lathe," lnd.-Anz., 112(21), pp. 48-50. (13 Mar 1990). A research project assignment resulted in the development of high speed lathe machining methods. The advantages of the new method include the machining of difficult materials (e.g. A1), high surface quality and a major reduction, up to 85%, in the required operation time. The equipment is CNC operated and uses a high speed central processing unit. The achievable precision is not compromised by the increased machining speed. (German).
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APRIL 1991 VOL 13 NO 2