プリント基板用GFRPの小径ドリル加工に関する研究

工具の肩部の形状が内部損傷に及ぼす影響

抄録

Recently, it has been necessary to improve the packaging density of printed wiring board (PWB), because the demand for size reduction of the electric devices has begun to increase. Therefore, the pitches between through holes in electric circuits have become fine for the high package density. On the other hand, various forms of damage occur around the holes after drilling. Among them, internal damage has attracted attention in order to prevent the reduction of the insulation resistance between the holes after through-hole plating, and the blow holes after soldering. Therefore, this study researches the damage factors around the drilled hole wall in small diameter drilling of a printed wiring board in order to prevent the ion migration between the holes. First, the internal damage around a drilled hole is examined. Next, the dynamic force (thrust force) during drilling is measured in order to examine the factors causing the internal damage around the drilled hole. As a result, it is shown that the outer corner of drill is one of the most important part in the small diameter drilling for the damage around the drilled hole.