Abstract
Micro welding of titanium eyeglass frames requires sound strength, good exterior appearances and stable production which were solved narrow HAZ (heat-affected zone), contactless method and stable production, which suit micro laser welding. The objective of this work is to fundamentally investigate butt welding conditions with a pulsed YAG laser beam for exterior appearances and joint strength. Eleven factors of the welding conditions which influence joint strength were evaluated from the viewpoint quality engineering. It was found that two factors of defocused distance and processing of welding surface of the welding parts led to fluctuation on the joint strength. Therefore sub-millimeter scale control of the laser irradiated point along optical axis and removal of impurities lead to brittle metallic compound on the surface produced sound strength of the joints. Furthermore, the optimized laser condition is applied to fabrication of components with a real shape of titanium eyeglass frames. The qualities of the obtained joints were confirmed by stripping test, cyclic bending test, metallographic observation and hardness determination. It was revealed laser welding method is more reasonable than conventional resistance brazing method.
