Prediction model for single-point diamond tool-tip wear during machining of optical grade silicon

摘要

In this study, the influence of various machining parameters on the diamond tool-tip wear during single-point diamond turning (SPDT) of optical grade silicon was examined. The results from ten face turning experiments conducted with identical diamond inserts are presented. The tool-tip wear was recorded in each trial as a dependent variable of the three varying independent variables, which are cutting speed, feed rate, and depth of cut. The findings indicate that the tool wear was sensitive to a combination of the cutting parameter of low speeds and high feeds. The effect of cutting depth was found to be the least influential. It was further established that the rate of diamond tool-tip wear in face turning of optical grade silicon decreases with decreasing tool-workpiece engagement time per revolution. Experimentally, a combination of high cutting speed and moderate feed rate generated a good surface finish with minimal tool wear. At this combination, diamond turning is conducted with reduced machining time, high rate of production, and a significant reduction in machining cost. Overall, the predominant type of tool wear observed was flank wear with flank wear land characterized by notches, micro-grooves, and micro-chippings. The results further suggest the possibility of prolonging the ductile cutting process by proper selection and control of cutting parameters.