Abstract
This paper describes the factors which affect the micro–drilled hole wall quality of various materials for Printed Wiring Boards (PWBs). The drill temperature in drilling monitored by a thermography was evaluated. Moreover, the workload on drill was investigated. The following conclusions were reached: (1) The surface roughness of drilled hole wall increases with the drill temperature in drilling. (2) The drill temperature tends to increase with the workload on drill caused by friction between hole wall and the land or margin of drill. Therefore, the reduction of the workload by the friction seems to be effective in order to obtain the high quality micro–drilled hole wall.
