Micro hole drilling of high frequency printed circuit board containing hard fillers

Abstract

High frequency printed circuit board (PCB), as the significant support for 5G technology, has been receiving intense attention from the increasing number of scholars. Concerning precision fabrication of high frequency PCBs, micro hole drilling is deemed as one of the extremely crucial challenges. In this study, the coated drill bits’ wear and micro hole quality were investigated through the drilling experiments of high frequency PCBs. Results showed that two kinds of coated drill bits exhibited well in terms of hole registration accuracy. Using diamond like carbon coated drill bits could obtain fewer burrs than drilled with diamond coated drill bits before drilling 200 holes, but the burr height increased very slowly with the increment of hole number when using diamond coated drill bits. Taking the combination of aluminum sheet and phenolic aldehyde board as the entry board was conducive to obtaining less burr, and the micro drill bits with helix angles of 40° and 42° were contributed to achieving less burr too. Additionally, decreasing the feed rate could lessen the hole blocking.