Drilling of Glass Epoxy Copper Clad Laminate: Influence of Direction of Fiber on Drilled Surface Conditions

Both surface roughness and inside failure of drilled surface occured during drilling copper clad laminates cause the loss of electric conduction and dielectric breakdown in using printed circuit boards. However, these phenomena haven't been cleared yet. Therefore, this investigation was conducted to examine the surface roughess and inside failure extent in relation with both number of drilled holes and number of laminates. These surface conditions were observed with a stylus profilometer and a SEM. Inside failure was examined by means of an optical method using the one layer glass epoxy lamina that is the same material as copper clad laminates. Following results are obtained. In the direction of fiber 30°/120°, the surface roughness shows the maximum value because of glass fibers dug up. In the case of 3 sets of laminates, surface roughness for the bottom laminate is smaller than that for the top one. Inside falure isn't influenced by both number of drilled holes and number of laminates, and inside failure extent is about 80μm.