Study on real-time detection of laser drilling in transparent hard and brittle materials by an external electric field

This research proposes to applied external electric field detect to the laser processing, Design and analysis of detection electrodes to detect plasma induced by laser processing, and then transmit the plasma signal to the controller in real time through evaluation board, the signal sampling rate of the evaluation board is 1 MHz, evaluation board can accurately detect the pulse repetition rate 0–500 kHz laser processing, the controller analyzes the plasma signal, according to the plasma signal, the controller controls the servo motor to change the focus position of the laser to achieve real-time detection of laser drilling processing, the result shows that Experiment of detect single-spot laser continuous processing on sapphire, the detection drilling depth increased by an average of 132.96%, and the average detection depth 587.05 μm. Experiment of detect 1 mm drilling laser processing on sapphire, the average inlet diameter is reduced by 8.04%, the average outlet diameter is increased by 336.2%, the average machine time is reduced by 61.8%.