Optical emissions for monitoring of the percussion laser drilling process

In percussion laser drilling, a sufficiently powerful laser beam is used for the formation of a hole on the workpiece. In this study, the investigation of utilizing optical signals, acquired by means of photodiodes and emitted from the processing zone for real-time monitoring, is presented. The correlation between the sensor output and the geometry of the hole, determined by the depth and upper diameter, is investigated, and the results are presented. In general, the results indicate that there is a strong correlation between the optical signal output and the diameter of the hole.