Papers by Keyword: Metal-Bonded Diamond Wheel

Abstract: Metal-bonded ball-headed diamond wheel with small diameter has been widely used in the ultra-precision grinding of optical parts, especially in the parts with complex surface. In-position precise dressing technique of ball-headed diamond wheel is the key technology to improve grinding precision. The effect of mechanical errors on the profile accuracy of wheel dressing were theoretically analyzed firstly. Afterwards a ball-headed diamond wheel dressing equipment based on electrical discharge principle has been designed and built. Orthogonal experiments have been carried out on the dressing equipment, and the dressing quality of wheels under different dressing electrical parameters were analyzed in terms of wheel profile accuracy and wheel surface micro-topography. The influence of dressing electrical parameters on the dressing quality were investigated and the best electrical parameter combination was obtained. Experimental result showed that the wheel profile accuracy can reach upward 0.8μm after dressing, and the protrusion heights of diamond grain were uniformity and the protrusion effect was better than without dressing.

Abstract: Silicon carbide (SiC) single crystal has many advantages comparing with silicon single crystal, such as wide band-gap, hardness and various stable physical properties at high temperature and severe chemical environments. SiC semiconductor substrate is expected to be applied to high power devices and sensor devices in the severe environments. The polishing process under ultraviolet-ray irradiation has been developed in our laboratory to achieve the mirror-finish process of single-crystal SiC. In this paper, after the confirmation of the elastic deformation behavior of SiC single crystal using the nano-indentation tester, pre-processings of SiC by lapping and constant-pressure grinding were performed to obtain good surface without brittle fracture region. The indentation tests indicate the single-crystal SiC shows a very high elastic recovery rate. SiC substrate was processed by the lapping and the constant-pressure grinding using the constant-pressure processing to avoid the cumulative residual stock removal. As many experimental results, the constant-pressure grinding is found to be suitable for the pre-processing of SiC substrates. Additionally, it is clarified that good surface roughness on the ground surface is achieved by using a diamond wheel with the same protrusion height of abrasive grains.