S1304-2-3 Relationship between surface profile and laser absorptivity in laser welding of transparent resin parts

Abstract

This paper investigates the relationship between surface profile and laser absorptivity in laser welding of transparent thermoplastic resin parts in order to clarify the desirable profile which provides high laser absorptivity. A diode laser with 920 nm wavelength was used for laser irradiation and PMMA was used as a test piece. Sandblasting and hot pressing were used as the preprocessing method to form the roughness and the surface of the test pieces was observed using scanning electron microscope (SEM). Laser absorptivity of each test piece was also measured. It is found that surface on which squarish asperities 5 μm on a side, as well as small asperities less than 1 jam size, provides high laser absorptivity.