Study on effects of process parameters on laser seal welding for ultra thin titanium shell

Due to the effects of manufacture techniques on specimen and heat distortion during welding, seal welding for ultra thin titanium shell is quite difficult. An Nd: YAG pulse laser system was used to seal 0.3mm thick medical titanium implant herein. The effects of process parameters including pulse wave shape, laser power, welding speed, defocusing amount, and shielding gas were investigated. Besides, tests of micro-hardness and micro-structure analyses on overlapped weld joint were discussed. Finally, parts of the welded specimens were analyzed by helium mass spectrum leakage detector. The experimental results show that flat wave shape is optimum choice for seal welding, reasonable collocation of laser power and welding speed guarantees the welding quality, and the weld bead color is good when the shielding gas flow rate is at 15 L/minute. The welding specification for sealing ultra thin titanium shell was confirmed through a serial of technique experiments. It provides reference for engineering applications and optimization of the seal welding further.