Study on surface quality in laser machining of GFRP for printed wiring board - temperature and damage at workpiece in drilling

This paper describes the relation between the temperature and the damage at the hole wall of GFRP for printed wiring board in laser drilling. First, the temperature is measured by a thermocouple at various positions on the drilled hole wall in laser drilling. Secondly, the width of damage is observed by an optical microscope and SEM after laser drilling. The temperature at thermal damage is clarified by comparing these results. Finally, the thermal transfer model paying attention to the thermal properties of glass fiber is proposed for the laser drilling. From these experimental and calculated results, the practical formula is derived in order to predict the damage width.