METHOD AND DEVICE FOR PREVENTION OF ADHESION OF DIRT AND CONTAMINATION ON OPTICAL PARTS IN LASER BEAM MACHINE

摘要

A method and a device for prevention of adhesion of dirt and contamination on optical parts in a laser beam machine, the method comprising the steps of injecting gas while inducing air between the head (3) of the laser beam machine and a processed material (M) from the rear of a plurality of injection nozzles (9c) disposed at specified distances in laser beam radiating direction in the state of not disturbing processing gas to prevent the adhesion of dirt produced during laser beam machining to the optical parts (31, 32) in the head (3); the device comprising a light receiving part (4) disposed on the upstream side of the optical parts (31, 32) in the head (3) and receiving reflected light and scattered light produced due to adhesion of dirt and contamination by reflecting or transmitting the light and a determination part (6) for comparing a received light value with a preset threshold.