Evaluation of Double-Sided Planetary Grinding Using Diamond Wheels for Sapphire Substrates

Double-sided planetary grinding as an efficient and precise machining method is used for the rapid thinning and flattening process of sapphire substrate. As an intermediate processing technology of sapphire substrate preparation procedure, many experiments are carried out to evaluate the lapping effect in the paper. Surface quality, processing efficiency, and surface dent depth, which all impact subsequent polishing processes, are evaluated. Firstly, the four stages of grinding process are analyzed to display the surface accuracy changing process of the sapphire substrates during grinding. Secondly, the effect of three main grinding parameters (grinding pressure, rotation speed of the grinding wheels, and the grain size of grinding wheels) on surface accuracy and processing efficiency are investigated. Finally, sapphire removal rate of about 10 mu m/min is achieved easily at the optimized condition with a good surface quality by double-sided planetary grinding. The double-sided planetary grinding with the ceramic-bonded diamond wheel is suitable for the rapid thinning and flattening of the sapphire substrate.