Glass-Bonded Silicon Carbide Grinding Wheels Improve Productivity and Surface Roughness

composition deposited on stainless steel substrates were studied using an indentation technique with a mechanical properties microprobe which allows measurement of film properties without contribution from the substrate material. A polishing technique was developed that gave consistent indentation measurements on films with initially rough surfaces. The elastic modulus increases linearly with increasing nitrogen content in the N:Ti range of 0.5-1.05, while the hardness of the film depends on other factors. Possible factors contributing to the hardness of the films are discussed. (Author abstract) 14 Refs. Presented at 16th International Conference on Metallurgical Coatings (ICMC) - Part II. 34, A. V. Galinskas, U. R. Y. Mikuckas, " E x p e r i m e n t a l Study of V i b r a t o r y Method and Means of Providing High Precision in the Process of Manufacturing Toothed Elements of Dividing Devices," Vibration Engineering (English Translation of Vibrotekhnika), 3(3), pp. 453-459. (1989). The precision of the angular position of dividing devices is determined by precision characteristics in the manufacture of the dividing elements of toothed disks. Based on analysis of existing methods and technical means and capabilities, the authors have developed, tested, and put into production an original method and device for final machining of face toothed disks for dividing devices. The essence of the method consists in treating two toothed disks that are to work as a pair with a special vibrodevice, while the working surfaces of toothed coupling are machined over the entire length of the relocation. 3 Refs. 35, P. Z. Takacs, E. L. Church, " F i g u r e and Finish of Grazing Incidence M i r r o r s , " 1989 Synchrotron Radiatim! Instrumentation (SRI) National Conference, Berkeley, CA (USA), 6-10 Aug 1989. 43 pages. Great improvement has been made in the past several years in the quality of optical components used in synchrotron radiation (SR) beamlines. Most of this progress has been the result of vastly improved metrology techniques and instrumentation permitting rapid and accurate measurement of the surface finish and figure on grazing incidence optics. A significant theoretical effort has linked the actual performance of components used as x-ray wavelengths to their topological properties as measured by surface profiling instruments. Next-generation advanced light sources will require optical components and systems to have sub-arc second surface figure tolerances. This paper will explore the consequences of these requirements in terms of manufacturing tolerances to see if the present manufacturing state-of-theart is capable of producing the required surfaces. 15 refs., 14 figs., 2 tabs. Brookhaven National Laboratory, BNL-4288% 36, K. Maekawa, 1. Ohshima, R. Murata, "Finite Element Analysis of Temperature and Stresses within an Internally Cooled Cutting Tool," Bulletin of the Japan Society of Precision Engineering, 23(3). pp. 243-246~ (Sep 1989). Contact pressure at the tool-chip interface is so high that lubrication or cooling of cutting tools by normally supplied cutting fluid is less effective for crater wear. Internal cooling is aimed at enforcing heat transfer into the coolant within a cutting took resulting in the drop of cutting temperature which is a governing factor of crater wear. This paper treats the design of an internally cooled cutting tool in a way of an optimum shape decision problem of continua, describes analytical procedures and shows some calculation results. 37, I. Yellowley, A. Adey, " F o r c e Models for Practical Multi-Edge Cutting Tools and Real Time Process Optimization," Factors Influencing Machining and Their Controls, 1990. ASM International, Materials Park, Ohio 44073. USA. The improvement of the productivity of metal cutting machine tools is dependent upon the capacity to optimize machining conditions. While the basic economics of the various processes are fairly well understood, practical operations result in machining parameters which vary considerably during a single block of an NC program, and during the removal of given geometric elements. Not surprisingly, most programming techniques do not allow for the calculation of instantaneous chip geometry and CNC systems do not normally allow the modification of metal cutting feedrates during a single block, or within a particular macro. Added to this, of course, is the inherent uncertainty which arises in many cases due to variations in blank dimensions; and calculations made at the programming stage have fairly large uncertainties associated with them. The development of an approach to the real time control of machining parameters in turning of 1045 steel is described. Graphs. 16 ref.--AA. 38, W. Johnson, S. Chandrasekar, "Forming Holes in Brittle Materials. An Antique Technique and its Report by Charles Babbage, 1792-1871," Journal of Materials Processing Technology, 21(1), pp. 43-50. (Jan 1990). In his biography, Passages from the Life of a Philosopher, Charles Babbage, an outstanding pioneer in computer technology, described a method of forming holes in brittle materials. This he had from one of his many 'practical' friends, the originator of the method not being known. The technique is of great importance to-day in relation to the working of ceramics. Close similarities are often described in present-day papers and thus it is fitting that historical knowledge of the method be known. (Author abstract) 10 Refs, 39, A. Majumdar, C. L. Tien, " F r a c t a l Characterization and Simulation of Rough Surfaces," Wear, 136(2), pp. 313327. (Mar 1990). Roughness measurements on a variety of machined steel surfaces and a textured magnetic thin-film disk have shown that their topographies are multiscale mad random. The power spectrum of each of these surfaces follows a power law within the length scales considered. This spectral behavior implies that when the surface is repeatedly magnified, statistically similar images of the surface keep appearing. In this paper the fractal dimension is identified as an intrinsic property of such a multiscale structure and the Weierstrass-Mandelbrot (W-M) fractal function is used to introduce a new and simple method of roughness characterization. The power spectra of the stainless steel surface profiles coincide at high frequencies and correspond to a fractal dimension of 1.5. (Edited author abstract) 18 Refs.

40, D. Herman, "Glass-Bonded Silicon Carbide Grinding Wheels Improve Productivity and Surface Roughness," Werkstatt Betr., 123(1), pp. 83-86. (Jan 1990). The process of bonding the abrasive grain with the bond material has a major influence on the operating characteristics of the grinding wheel. The selected results described show by their parameters that grinding wheels with enveloped abrasive grain in a glass bond offer more benefits than those currently used in the industry. A determining factor is the presence or absence of SiO 2 in the bond area. Due to the good wettability with borosilicate glass of the titanium dioxide enveloped silicon carbide grains, the abrasive is uniformly distributed within the glass matrix, This has a substantial effect on the behavior of the grinding wheels in operation. Graphs. 7 ref.--AA. (In German).

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J A N U A R Y 1991 VOL 13 NO 1