Seal device of light path system in laser beam machine

摘要

The invention provides a laser beam machine having a light path duct with improved dust proof property. A light path system of a laser beam machine comprises a light path duct 10 having a U-shaped cross-section with the upper end opened, and a light path 12 into which clean air is fed. Gutters 110 are disposed on both sides of the light path duct 10, and liquid 120 is filled therein. The laser beam extraction unit 50 traveling on the light path duct 10 has panels 150 disposed on both sides thereof, and a skirt portion 152 formed at the end of each panel 150 is immersed in the liquid 120, thereby forming a liquid seal.