2023 Volume 67 Issue 9 Pages 509-516
This study was performed to clarify the effects of flank wear and margin wear on drilled hole quality in printed circuit board (PCB) hole drilling. We performed a series of hole drilling tests in PCBs using a drill with only flank wear and a drill with only margin wear, and investigated the effects of each drill on hole positional accuracy, hole bending, and roughness of the inner wall surface. Compared to flank wear, margin wear resulted in poorer hole position accuracy, hole bending, and roughness of the inner wall surface. As margin wear increased, the cutting force on the Lissajous curve on the plane perpendicular to the drilling direction increased, and hole bending and hole position accuracy deteriorated. When using a drill with margin wear, the reverse taper drill margin rubbing the inner wall of the hole causes fraying of the glass cloth. Therefore, the amount of protrusion of glass cloth on the inner wall of the hole increased, and the roughness of the inner wall of the hole deteriorated.
