Laser removal of material from workpieces

摘要

To ascertain the beam intensity threshold at which the intensity of a laser beam will just be sufficient to engrave a workpiece, the value of a beam-intensity control signal is progressively increased or decreased until engraving starts or stops, this being sensed by detecting the initiation or termination of ionization which occurs when the beam intensity is above the threshold value adjacent a part of the workpiece which is being subjected to the action of the laser beam.