METHOD AND DEVICE FOR LASER BEAM MACHINING

摘要

PROBLEM TO BE SOLVED: To prevent the edge part of a cut protective sheet from being turned up during cutting and machining and prevent the contamination of a condensing lens by back-flow of gas by stopping the supply of the gas to the second gas passage by a malfunction detecting means on the occurrence of such an abnormal condition that the gas supplied to the second gas passage is made to flow backward to the first gas passage due to a cutting failure and the like. SOLUTION: In a method and a device for laser beam machining, a workpiece 3 is cut and machined while emitting the gas from the first gas passage 6 and the second gas passage 7 toward the workpiece 3 protected by the protective sheet 5. The pressure of the gas from the passage 7 is made higher than that of the gas from the passage 6. In addition, this device is provided with the malfunction detecting means 16 fitted with a flowmeter 17 and a pressure gage 18 in order to detect such a malfunction that the gas supplied to the passage 7 flows backward to the passage 6 for the purpose of stopping the supply of the gas to the passage 7 at the detection of the malfunction.