Working method for extremely narrow hole by means of laser

TLDR: In this article, a laser beam reflective coating layer is formed on the surface of the processed material to facilitate the work for an extremely narrow hole, by irradiating the pulse laser to make a hole whose diameter is smaller than the laser beam diameter.

Abstract: PURPOSE:To facilitate the work for an extremely narrow hole, by irradiating the pulse laser to make a hole whose diameter is smaller than the laser beam diameter by forming a laser beam reflective coating layer, where an under-hole is processed, on the surface of the processed material. CONSTITUTION:Coating layer 5 of a high laser beam reflection factor is formed on the surface of processed material 3. At this time, under-hole 6 whose diameter is smaller than the diameter of laser beam 1 is formed in coating layer 5. Next, the output of the pulse laser irradiated to under-hole 6 is set to a low value when the hole is shallow at the initial stage of holing work. Then, base metal fusion region 7 is restrained to a small quantity, and coating layer 5 is not fused under the influence of fusion region 7. The output of the pulse laser is set to a higher value according as the hole is deeper. At this time, base metal fusion region 7 becomes deeper, and coating layer 5 is not fused by the influence of region 7, and thus, a very narrow hole is punched in processed material 3.