Elucidation of phenomena in micro-drilling for printed wiring boards containing high-hardness fillers

Investigation of drill wear and temperature during drilling

Abstract

This paper describes micro-drilling processes of printed wiring boards (PWBs) containing high-hardness and high-thermal conduction fillers. When processing these PWBs, drill tools show severe wear because the filler has high hardness. Therefore, we examined the characteristics of drill wear and showed the usefulness of diamond-coated drills. The diamond-coated drill is effective against PWBs with higher filler filling rate. Moreover, we investigated the cutting force and PWB temperature during drilling. Macroscopically, cutting force was seen to be more significantly influenced by drill wear compared to material physical properties. On the other hand, microscopically the PWB temperature during drilling was significantly influenced by material physical properties.