On-machine precision form truing of arc-shaped diamond wheels

Abstract

In order to realize the efficient and precision truing of arc-shaped diamond wheel for precision grinding of spherical, aspherical and free-form surfaces, a novel on-machine precision form truing of resin and metal bonded arc-shaped diamond wheels is proposed utilizing rotary green silicon carbon (GC) rod. Through this on-machine rotary GC rod (ORGCR) mutual-wear truing, any required radius of wheel arc profile could be formed by programmed truing paths, meanwhile, the vertical direction position error of the wheel center could be corrected after truing. Firstly, the principle of ORGCR mutual-wear truing for arc-shaped diamond wheel was introduced, and new evaluation methods of truing performance and truing ratio were provided. Then the truing performance and truing ratio were observed for different grains and bond of arc-shaped diamond wheels, the effects of ORGCR mutual-wear truing parameters on profile radius and form accuracy of wheels were investigated. Finally, the convex aspherical surface of single crystal silicon was ground by trued arc-shaped diamond wheel. The experimental results showed that the resin and metal bonded diamond wheels could be efficiently and precisely trued with high truing ratio. The form error of wheel arc profile reached 2.5–6μm/3mm which decreased about 90% compared to pre-truing wheel. Besides, the diamond grains were well distributed on the wheel surface, and protruded out of the wheel bond after truing. The precision aspherical surface of single crystal silicon with the form accuracy PV of 507nm and the average roughness Ra of 57.1nm was achieved by parallel grinding with the trued D7 resin bonded wheel.