Wear mechanisms of Ti(C7N3)-based cermet micro-drill and machining quality during ultra-high speed micro-drilling multi-layered PCB consisting of copper foil and glass fiber reinforced plastics

Printed circuit board (PCB) consists of copper foil and glass fiber reinforced plastics, and glass fiber reinforced plastics belong to the typical hard machining material, which leads to the poor surface finish and rapid tool wear. The new Ti(C7N3)-based cermet (TC) micro-drill was in-house developed to machine PCB S1000, the wear mechanisms and the machining quality were investigated comprehensively, while diffusional interactions between the TC and S1000 were also implemented. It was concluded that the main wear mode of the TC micro-drill was the flank wear, the area of the flank wear showed a trend of first increasing and then decreasing along with the feed per tooth, while no tool breakage occurred during the micro-drilling process. The main wear mechanisms contained the abrasive wear, adhesion wear, and diffusion wear. Moreover, both the 1st and 2nd layer PCBs had a good machining quality. Therefore, the TC micro-drill is suitable for machining PCB S1000.