Papers by Author: Zhi Hui Xia

Abstract: As the consumer market in the optics, electronics and aerospace industries grows, the profile accuracy demand for ultra-precision flat, spherical and aspheric optical surface micro-lens increases. Previous studies have found that machine system accuracy, tool alignment error and tool radius measurement error impact greatly on the profile accuracy of the machined surface. In this paper, we developed a grinding system based on the ultra-precision diamond lathe, presented a unified mathematical model of effects of all the geometric errors to the shape error by using the multi-body system theory. Aiming at the main source of profile error, the practical mathematical model is derived, and their propagation coefficients to profile error are calculated. By means of simulation analysis and grinding experiments of spherical part of tugnsten carbide, we conclude that the radial tool alignment error is the main influencing factor for the profile error of spherical surface; while tool radius measurement error influence the radius of sphere only.

Abstract: Ultrasonic vibration is applied to diamond turning of special stainless steel to decrease diamond tool wear and improve the surface quality of the workpieces. It reviews the principle of diamond turning of special stainless steel by applying ultrasonic vibration combined with gas shield. Compared with the ordinary machining method, cutting temperature and cutting force are greatly reduced when machining by application of ultrasonic vibration, and the appetency between a diamond tool and Ferrous atom of a workpiece is also minimized as gas shield application. The Experiments of cutting special stainless steel workpieces show that the surface roughness Ra is less than 0.15μm and flank wear-width is less than 5μm when cutting distance is up to 2000m. It takes research on the effect of cutting parameters to surface roughness and tool wear. The experiment result shows that the amplitude is the most important factor which effects tool wear and surface roughness most.