Diamond film polishing with abrasive-liquid jets: an exploratory investigation

construction of neutron guides, it was necessary to reach the same results on much larger pieces. We describe the design and set up of special equipment for super polishing the substrates, and sputtering the multilayer-control equipment which has been realized for factory acceptance of each piece. 20 Refs. 15. Shimizu, Hiroyuki; Takeuchi, Yoshimi. Development of a cupped diamond wheel for ultrasonic surface grinding - CAE approach to the optimal design of the wheel. Journal of the Japan Society of Precision Engineering. 1993 Jan; 59(1): 137-142. The study deals with the development of a new cupped diamond wheel used in ultrasonic surface grinding of brittle materials such as fine ceramics. The wheel has a larger diameter and higher stiffness than the usual wheel, therefore it allows the user to grind brittle materials efficiently and precisely. By using the CAE system which has been developed to design an optimal high-intensity ultrasonic system, the wheel is designed optimally so as to resonate in half-wave at the resonance frequency of an employed ultrasonic vibrator. Then, the wheel is produced on the basis of the designed values, its vibrational properties are measured, and the experiments using it in ultrasonic surface grinding are carried out. As a result, the reasonability's of the designed values are proved, and the potentiality of the wheel is confirmed. 8 Refs. 16. Sugita, Kazuhiko; Yamakawa, Yoichi; Sakakibara, Norio; Hori, Nobumitu; Unno, Kunihiko. Development of a noncircular high speed generating mechanism by hybrid system with VCM and PZT. Journal of the Japan Society of Precision Engineering. 1992 Sept; 58(9): 1503-1508. This paper presents a high speed non-circular generating mechanism for a piston-head of a reciprocating engine. An ordinary piston-head has the complicated cross-section whose profile is ellipse with harmonic components, so that it is difficult to machine the workplace at high speed by the copying lathe which is used generally. In order to solve this problem, an NC-tool positioning mechanism using hybrid system which has both the VCM's feature, long stroke, and the PZT's feature, fast response was developed. And a periodic learning control method was also developed which corrects the NC data in the frequency domain. The PZT is mounted coaxially on the top of externally pressurized slideway which guides the VCM, and the sum of these two actuators' displacement becomes cutting tool's displacement. On account of sharing the harmonic components of profile, i.e. lower components to the VCM, higher components to the PZT, the piston-head can be machined more than three times as fast as the conventional system at the speed of 3,000 min -1 , resulted in the accuracy of +__3 I~m tolerance. 7 Refs. 17. Oiwa, Takaaki; Kyusojin, Akira. Development of precise cylindrical grinding by ball centers: effect of ball wear. Precision Engineering. 1993 Apr; 15(2): 106-111. In high-precision cylindrical grinding and precision measurement, it is known that accurate and inexpensive steel balls used in place of cone centers enable one to grind and to measure the workpiece accurately without the influence of the misalignments and geometrical deviations of the center holes. The purpose of this study is to explain the supporting characteristics of these ball centers. In this article, endurance tests were performed and ball wear was measured to investigate the effect of the wear on the rotational accuracy and the roundness of the workplace. The main results obtained are as follows. (1) The rotational accuracy and the roundness of the workplace remained at high levels during the endurance test of 3 hours regardless of the ball wear. Consequently, the wear had little effect on the accuracy. (2) The contact points between the ball and the holder gradually shifted to other points that were not yet worn. This averaging effect maintains the rotational accuracy at a high level. (3) Lubricating the supports every quarter hour reduced the ball wear to half. Moreover, the lubrication was effective in preventing the ball from exfoliating. Therefore, there is no need to be concerned about ball wear in ordinary circumstances. 6 Refs. 18. Hashish, M. Diamond film polishing with abrasive-liquid jets: an exploratory investigation. Precision Machining: Technology and Machine Development and Improvement - Production Engineering Division. New York, NY: American Society of Mechanical Engineers; 1992: 29-41. Vol. PED 58. An exploratory experimental investigation was conducted to determine the feasibility of polishing diamond films with abrasive-liquid jets. A nozzle system that produces a high-velocity radial flow with zero or near-zero impact angles was used for polishing tests. The radial flow is produced between the nozzle and the workpiece in the form of a boundary layer. The abrasive particles are acted upon by hydrodynamic forces to effect polishing and microgrinding operations. The relatively high particle flow rates (10 g/s) and velocities (over 150 m/s) result in relatively high processing (polishing or microgrinding) rates. The inertial effect of the abrasive particles appears to contribute significantly to the material removal. A diamond film was polished from 3 to 1.3 l~m at a rate of 2.7 t~m/s/mm2 using 600-mesh SiC abrasives. 19 Refs. 19. Lundin, R. L; Stewart, D. D; Evans, C. J. Diamond tool machining of materials which react with diamond. 1991 Apr; This invention is comprised of an apparatus for the diamond machining of materials which detrimentally react with diamond cutting tools in which the cutting tool and the workpiece are chilled to very low temperatures. This chilling halts or retards the chemical reaction between the workplace and the diamond cutting tool so that wear rates of the diamond tool on previously detrimental materials are comparable with the diamond turning of materials which do not react with diamond. 20. Lucca, D. A; Seo, Y. W; Rhorer, R. L. Effect of the tool-workplece interface on energy dissipation in ultraprecision machining of aluminum. Proceedings of the Seventh Annual Meeting of the American Society for Precision Engineering; 1992. Advances in both the efficiency of the ultra-precision machining process and the quality of the final workplace are being limited by our incomplete understanding of the governing process physics. Of late, there have been increased efforts to extend this understanding. In this paper, the authors' work focuses on the development of physical models of the mechanical energy dissipation and resulting temperatures when machining at depths of cut less than several micrometers. The authors' approach has been to attempt to accurately identify the regions of mechanical energy dissipation in the tool-chip-workplace zone, and subsequently equate mechanical work to heat for a prediction of the temperatures which result. An overall energy balance indicated that at depths of cut below several micrometers, shearing in the shear zone and 296

OCTOBER 1993 VOL 15 NO 4