YAGレーザを用いた微細加工におけるドロス生成に関する研究

抄録

YAG laser has actively been used for precision micro machining, since it has become possible to get stable and high quality beam and the spot diameter can be focused less than 100 micrometers. High energy beam machining with YAG laser or CO₂ laser is heat energy machinig accompanied with heating, fusion, evaporation processes, therefore the adhesions of spatter and dross to base material lead to the deterioration of machining integrity. In this paper, the dross generation mechanism in precision micro cutting of thin plate with pulsed YAG laser is experimentally investigated.
Main conclusions obtained are as follows:
(1) In a single pulse machining, the spatter scatters on the base material surface at irradiation side and the dross sticks around the hole at exit side.
(2) Oxygen assist gas makes the mobility of melting material increase, which leads to the decrease of the adhesion of dross.
(3) The height of dross is greatly affected by the beam overlap rate, and it takes maximum when the beam overlap rate is about 93%.
(4) The dropout phenomenon of dross is occurred when the beam overlap rate is more than 96%.
(5) The generation of dross is restrained by shortening the gap distance between the nozzle of assist gas and the workpiece.