Dry electro-contact discharge mutual-wear truing of micro diamond wheel V-tip for precision micro-grinding

摘要

A novel V-tip truing of metal-bonded fine diamond wheel is proposed using a hybrid of electro-contact discharge (ECD) and mechanical mutual-wear between diamond wheel and electrode without any coolant. The objective is to explore an eco-efficient truing of micro diamond wheel V-tip for micro-grinding. First, a V-tip truing of metal-bonded #600 diamond wheel was performed with the ideal V-tip angle of 60°; then the effects of dry discharge variables were analyzed on wheel V-tip form error, wheel V-tip angle and wheel V-tip radius; next, truing ratio and truing efficiency were observed; finally, the micro-groove of quartz glass was ground by using the trued diamond wheel V-tip. It is shown that continuous spark discharges may be maintained during truing as the pulse voltage ranges 5 V to 7 V, leading to the least wheel V-tip form error, the least wheel V-tip angle and the least wheel V-tip radius, respectively. When the suitable discharge conditions are employed, the Dry ECD mutual-wear truing may achieve less wheel V-tip form error, less wheel V-tip angle and less wheel V-tip radius than mechanical truing. It may also improve truing ratio by about 350 times and truing efficiency by about 59 times against mechanical truing, respectively. After micro-grinding of quartz glass using the trued diamond wheel V-tip, the integrated micro-groove may be ground with the average absolute angle error of 0.59° and the average surface roughness of 0.128 μm. It is confirmed that the micro diamond wheel V-tip can be fabricated by Dry ECD mutual-wear truing for precision micro-grinding of hard and brittle material.