Novel Dressing Technique for Diamond Wheels

absolute angle can be derived from the optical encoder which uses a LED, photodiode array and a coded disc consisting of three tracks. The accuracy of angular measurement for a prototype encoder was as high as 1/1,000,000, and the encoder can respond up to 3,000 rpm. The shaft revolutions are tallied by a magnetic bubble counter which uses a 'memory wheel' principle to count up to 32,487 turns. No electrical energy is used to store data or count revolutions. 2 Refs. 79, A. V. Galkov, A. A. Ivanenko, A. A. Orap, V. S. Barkov, " M u t u a l Effects of Technological Factors on Superfinishing with Stones made from SliM," Soviet Journal of Superhard Materials. l 1(6), pp. 81-86. (1989). The mutual effects of technological factors in the superfinishing of steel components with ceramic-polymer based SHM are studied. It is shown that the workpiece roughness and the metal removal rate can be changed over a wide range by the effects of factor interaction. It is concluded that the interaction between the different factors must be allowed for in assigning machining conditions and in selecting an abrasive material. (Author abstract) 2 Refs. 80, N. Ozawa, Y. Kitamura, T. Kohno, K. Mitsui, Y. Okazaki, "A New Measuring Method for Spindle E r r o r Motion using a Cube-corner Prism and Laser I n t e r f e r o m e t e r s . I. Principle of the Method a n d P r e l i m i n a r y E x p e r i m e n t , " J. Jpn. Soc. Precis. Eng. (Japan),, 56(2), pp. 381-7. (Feb. 1990). A new measuring method is proposed for evaluating error motion of spindle rotation, where three laser beams enter through interferometers to a cube-corner prism (CCP) mounted on a spindle-end. The method is verified on an optical bench, and is applied to in-process measuring experiments for the spindle of the surface grinding machine. The noise level of the measuring system is found to be approximately 0.07 pm and the dynamic behavior of the rotating spindle is measured accurately during surface grinding operations. (In Japanese). 81, Qiang Zhang, Peizhen Deng, Fuxi Gan, "A New Surface Polishing and Defect Revealing Etchant for Sapphire," Mater. Lett. (Netherlands), 9(4), pp. 128-32. (Feb. 1990). A new optimum surface-polishing and defect-revealing etchant for sapphire single crystals is described. Etching is accomplished by immersing wafers in molten borax at a temperature above 800 °C. Dislocations and twin lamellae in the wafers have been revealed by the etching method and X-ray transmission topography with comparable results. 82, V. M. Huynh, "Non-contact Inspection of Surface Finish," SME Technical Paper (Series), (1989). (FC89-343). A noncontact measurement technique was developed to measure the surface finish of machined parts. The system uses a machine vision system to capture the magnified image of a surface which is illuminated by a white light source at a shallow grazing angle. Grey-level histograms of the image were obtained to derive optical roughness parameters which could be related to the average roughness value R a measured by a profilometer. Calibration curves were obtained for different machining processes such as lapping, grinding, reaming, and turning with roughness values up to 500 micro-inch. This method provides a fast way of assessing surface roughness which can be adapted for use in industrial environments. (Author abstract). 83, D. Hayes, "Noritake Diamond Industries," Industrial Diamond Review, 50(536), pp. 29-30. (Jan 1990). Now still in its early stages, the growth of ceramics applications has involved Japan's diamond tool industry from the onset. Toolmakers are receiving a stream of enquiries from customers wanting to machine hard ceramics with the same high performance results as in metal machining. For Noritake Diamond Industries Co Ltd, the challenge posed by the introduction of new ceramics is being viewed as the inevitable extension of a wider corporate involvement with ceramic materials stretching back to the beginning of this century. The company currently is making preparations to accommodate accelerating business growth in the 1990s which will follow as diamond tool applications continue to grow rapidly in many sectors of Japanese industry. This article discusses the innovative products offered by this company. 1 Ref. 84, M. Rezaei, T. Suto, H. Noguchi, T. Waida, "Novel Dressing Technique for Diamond Wheels," Industrial Diamond This paper describes a comprehensive programme to develop suitable dressing techniques for vitrified bond diamond wheels. Among various dressing tools, the rotary diamond cup dresser was able to partially restore wheel sharpness. However, this was possible only at the cost of high wear of the diamond particles in the cup dresser. Further investigation of nonconventional dressing techniques showed that high efficiency dressing can be performed by a ceramic block or a slitting cutter. These dressing methods are referred to as 'Forced dressing' and 'Cutter dressing' respectively. The practical advantages and disadvantages of each dressing method are discussed. (Author abstract) 6 Refs.

Review, 49(535), pp. 258-261. (Jun 1989).

85, T. Nakagawa, H. Ohmori, K. Suzuki, T. Uematsu, Y. Hamano, O. Kamigaito, T. Kishi, M. Sakai, "Novel Efficient and Precise Grinding Technology for Structural Ceramics," MRS International Meeting on Advanced Materials, Volume 5 Structural Ceramics~Fracture Mechanics, Tokyo (Japan), 30 May - 3 Jun 1988. pp. 159-169. Materials Research Society, Pittsburgh, PA (USA). A review of research to produce more efficient and precise methods for grinding structural ceramics is presented. Consideration is given to the development and application of a cast iron bond diamond grinding wheel, three-dimensional NC grinding using machining centers and turning centers, and on-machine etectrodischarge trueing. The application of ultrasonic vibration to a grinding wheel to reduce the grinding force and the combination of vibration and electrodischarge machining are discussed. Also, mirror grinding and stable grinding with in-process dressing are examined. 86, I. A. Khramtsovskii, V. I. Pshenitsyn, V. A. Stepanov, V. A. Tsymbal, Y. G. Moshkarov, "Optical Characteristics and Composition of the Surface Layer of Mieroporous Glass," Soviet Journal of Glass Physics and Chemistry, 14(2), pp. 138-143. (Jan 1989). The refractive index, thickness, and chemical composition of the surface layer of microp0rous and untreated sodium borosilicate glasses were investigated as a function of the conditions of the mechanical treatment. On the basis of a proposed optical model of a nonuniform glass it is shown that when a preliminary polished untreated sodium silicate glass is leached, a surface layer with a refractive index less than in the volume of the glass forms to a depth of 0.6 gm. Polishing of the microporous glass leads to the formation of a surface layer 0.1-0.2 gm thick with a refractive index which is higher than in the volume of the glass. The

76

JANUARY 1991 VOL 13 NO 1