絶縁性AlNセラミックスの微細放電加工特性

概要

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As a sintered AlN ceramics material have the superior thermal conductivity and high electrical insulation properties. However, AlN is too brittle to machine for the precise and micro product by mechanical machining method, the application field is restricted. On the other hand, many insulating ceramic materials could be machined precisely by EDM with the assisting electrode method. As reported before, the removal rate of high thermal conductivity material such as AlN, SiC, and diamond is lower than other insulating materials. In this research, to obtain the better machining properties on the sintered AlN ceramics, effects of tool electrode polarity and working fluid in RC discharge circuit were investigated on the electrical discharge machining characteristics. As a result, the higher removal rate and the larger electrode wear ratio were shown in the tool electrode polarity of positive. Moreover, aluminum element was observed as the component element of electrical conductive layer on the machined surface. Using the decomposed aluminum layer as the electrical conductive layer, an AlN could be EDMed in demineralized water instead of working oil. The removal rate and tool electrode wear ratio in deionized water was three times higher and three times lower respectively than that of working oil.
公益社団法人精密工学会の論文