The effect of drilling parameters on the wicking in high density PCB processing

Wicking is one of the important factors that cause the internal short of Printed Circuit Board (PCB), and directly restrict the pitch of holes. In this paper, orthogonal experimental design method is used to study the effect of five drilling parameters on the wicking. The five factors are rotation speed, feeding speed, retracting speed, drill life and stack number. The result shows that the order of the influencing factors is as follows: stack number, drill life rotation speed, retracting speed, feeding speed. It is found that the optimum parameters combination is rotation speed of 150 kr/min, feeding speed of 38 mm/sec, retracting speed of 280 mm/sec, drill life of 1600 hits and stack number of 1 PNL/stack.