Method and device for prevention of adhesion of dirt and contamination on optical parts in laser beam machine

A method for preventing the fouling of optical components in a laser machining system which irradiates a laser light to machine a workpiece within a flow of machining gas, the method comprising the steps of:

• into a space between a workpiece and optical components that condense the laser light from a light source and irradiate it onto the workpiece, injecting first shielding gases from a plurality of first injectors disposed at stipulated intervals in a direction in which the laser light passes, so as not to disturb the flow of machining gas, in order to shield the optical components from fumes, spatter and dust arising during laser machining, while inducting air from behind the plurality of first injectors, wherein at least one of the plurality of first injectors disposed closer to the optical components than the other first injectors directs the first shielding gas toward the first shielding gases from the other injectors;
• unidirectionally guiding the first shielding gases with a pair of side plates disposed on sides of the plurality of first injectors;
• isolating the space from the laser machining with at least one flow-straightening plate disposed between the plurality of first injectors and the and workpiece;
• and
• injecting a second shielding gas directly onto the optical components from at least one second injector provided immediately below the optical components and above the plurality of first injectors.