Characterization of Printed Circuit Board Micro-Holes Drilling Process by Accurate Analysis of Drilling Force Signal

Drilling force directly affects the micro drill life and micro hole quality in the micro hole drilling of printed circuit board (PCB). But in the micro hole drilling process, the signal-to-noise ratio (SNR) of drilling force signal is low. Drilling force signal often submerged by noise signal, these brings great difficulty to measurement during PCB drilling process. Therefore, it is urgent to improve the SNR of drilling force signal in PCB drilling process. The observed signal of drilling force is obtained by PCB micro hole drilling experiment. Based on the cyclostationary and time domain accumulation theory, the drilling force signal is quadratic filtered, and the filtering effect of the filter on the drilling force signal is evaluated. In this paper, a composite multiple filter is designed to improve the SNR of drilling force signal rapidly and efficiently (SNR increased by 11.76 dB), realize the accurate description of the PCB micro hole drilling process.