抄録
In order to establish the mechanism of laser machining, machinability of various metals with different thermal properties was investigated. Metal plates were irradiated with one shot of the YAG laser pulses, and melting and removing processes were examined by observing machined shapes. The obtained results are as follows. (1) There exist four regions of the irradiation power density, where (a) only the melt zone is formed, (b) both the melt zone and removed zone are formed, (c) only the removed zone is formed, and (d) a laser plume is generated. (2) At a fixed power density the machined depth increases with increasing irradiation time, but is saturated at the depth that depends on the power density. (3) The machining processes in various metals, in spite of the wide variation of thermal properties, can be analyzed with the same machining mechanism. (4) Machinability indexes which give the easiness of machining with the pulsed YAG laser were determined for several materials. (5) Movement of the heat source point in the metal plate was estimated from the relation between the power density and the melt diameter.
