Production of Flat Optical Elements for Millimetre and Submillimetre Ranges on Commercial Numerically Controlled Machines

94, W. B. Lee, "Prediction of Microcutting Force Variation in Ultra-precision Machining," P r e c i s i o n Engineering, 12(1), pp. 25-28. (Jan 1990). Cutting force variation in machining has been associated with machine tool chatter, mode of chip formation and variable undeformed chip thickness. In ultra-precision machining, the variation in microcutting force has its origin in the changing crystallography of the material being cut. A physical model is presented to predict the pattern of micro-force variation when crystals of different crystallographic orientations are being machined. Methods for minimizing the cutting force fluctuation in polycrystalline materials are discussed. 10 Refs. 95, B. Rajmohan, V. Radhakrishnan, "A Preliminary Study on In-process Monitoring of Finish in S u r f a c e Grinding by Chip Radiation Measurement," Proceedings of 2nd IMEKO TC14 International Symposium on Metrology for Quality Control in Production, Beijing, China, 9-12 May 1989. pp. 97-103. Int. Acad. Publishers. Beijing, China. Grinding is a process where the finish produced is of critical significance. Many methods have been suggested for monitoring the finish of the surface produced, during grinding. The authors deal with the feasibility of instrumentation based on monitoring the chip radiation~ during surface grinding using a CCD array. 96, W. E. Barkman, E. F. Babelay, T. L. Hebble, R. R. Williams, "A Process Monitoring S t r a t e g y for a Precision Flexible Manufacturing System," International symposium on gas-liquid two-phase flows in conjunction with the winter annual meeting of the ASME, Dallas, TX (USA), 25-30 Nov 1990. pp. 11. American Society of Mechanical Engineers. For a number of years, the Oak Ridge Y-12 Plant has been involved in an endeavor which is described as a Precision Flexible Manufacturing System (PFMS). The objective of this project is to enhance the existing manufacturing operations for the production of precision hemispherical workpieces. The present fabrication process uses T-base lathes, similar to the one shown in figure 1, which are equipped with a Computer Numerical Control (CNC) system. The CNC systems are coupled to a host computer over a local area network (LAN). Currently, this link is used to download machining part programs and upload limited process information. While the enhanced system will use the same machine tools and LAN, additional capabilities will be provided to perform automatic tool changing, part and fixture handling, on-machine gagging, and chip control. The project's quality goals are to automatically manufacture workpieces to tolerances of + 0.0005 in. on contour and + 0.001 in. on wall thickness with a 3 to 5 sigma level of confidence. The parts will range from 4 to 10 in. in diameter with a wall thickness as large as one inch. 2 refs., 6 figs. 97, E. Westkamper, P. Maskus, "Process Simulation When Honing," ZWF Zeitschrift fur Wirtschafiliche Fertigung und Automatisierung, pp. 478-82. (Sept. 1990). Honing as a precision machining technique is wide spread. Due to the complex interrelationship of various parameters, process control is often characterized by statistics and calls for experienced machinists. Computer-aided process simulation permits the prediction of expected machining results and is therefore a contribution towards increasing quality and efficiency. (German) of F l a t Optical Elements for M i l l i m e t r e and Ranges on Commercial Numerically Controlled Machines," Computer Optics, pp. 133-8. (1989).

98, E. D. Bulatov, S. A. Gridin, A. A. Danilenko, " P r o d u c t i o n

Submillimetre

Consideration is given to the issues arising in the production of flat optical elements for millimeter and submillimeter ranges on commercial industrial machines with numerical control. A method for the production of flat optical elements on a numerically controlled turning machine is described, together with the appropriate algorithm. Much attention is paid to the technical details of making a cylindrical lens on a numerically controlled milling machine. Methods enabling the production of flat optical elements with specified accuracy on such a machine are described, as well as algorithms for control programs. The flat optical elements produced by these methods on commercial numerically controlled machines are briefly described. 99, Y. V. Zaikin, Y. V. Ashkerov, "Refinement of Technology for Fabricating Metal M i r r o r s , " Soviet Journal o/" Optical Technology, pp. 28, 36 90-1. (Feb. 1990). As a result of metallographic examinations of the surface structure of metal mirrors, produced by the diamond turning method, an additional fine diamond grinding operation is suggested in order to reduce significantly the thickness of the damaged surface layer. 100, B. M. Bromberg, "Relationship Between Coaxiality Errors of Machined Faces," Soviet Engineering Research, 9(5), pp. 112-117. (1989). Tolerances on the forms and positions of machined faces are specified in GOST 24643-81, and design and technological methods and devices for achieving these tolerances and reducing coaxiality errors are discussed in the literature. The present article considers only the relationship between errors. 3 Refs. 101, M. Anjanappa, D. K. Anand, J. A. Kirk, E. Zivi, M. Woytowitz, E. A. Puente, L. Nemes, "Retrofitting a CNC Machining Center with a Magnetic Spindle for Tool Path E r r o r Control," Information Control Problems in Manufacturing Technology 1989. 6th IFAC/IFIP/IFORS/IMACS Symposium, Madrid, Spain, 26-29 Sept. 1989. pp. 511-15. Pergamon Oxford, UK. The use of a magnetic bearing spindle to machine thin rib components, such as microwave guides, provides the capability to minimize tool path errors along with the benefits of high speed machining. Tool path errors, defined as the distance-difference between the required and actual tool path, can be controlled using the unique features of the magnetic bearing spindle. This paper deals with the control and interfacing issues involved in retrofitting a vertical machining center with an S2M-B25/500 magnetic spindle. The resulting facility, one of a kind in the United States, has been successfully tested by generating (i.e~ cutting) a surface whose profile follows a control input signal. 102, Y. Endo, Y. Takatsuji, H. Notodani, S. Yamada, 1. Tsukuda, "Shape of Sintered Diamond Tools for Cutting AI-17Si--T6 Alloys," 76th Conference of the Japan Institute of Light Metals, 1989. Japan Institute of Light Metals Nihonbashi Asoki Seimei Bldg. 1-3 Nihonbashi 2 chome, Chuo-ku, Tokyo, Japan. Extruded and T6 heat-treated hypereutectic A1--Si alloys have higher strength and better wear resistance in comparison with cast alloys, because the fine Si particles are dispersed homogeneously in the matrix. However, machining of the alloys is difficult. For longer tool life, sintered diamond cutting tools are used. However, the side rake angle of cutting tools on the market is either -- p/36 or p/36 rad and the relation between the life and the side rake angle

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