Parametric Optimization of Laser Conduction Welding between Stainless Steel 316 and Polyethylene Terephthalate Using Taguchi Method

Abstract

A pulsed Nd:YAG laser with a fiber optic delivery system was used to accomplish a dissimilar joining of 316 stainless steel (SUS316) to polyethylene terephthalate (PET). Laser Conduction Welding (LCW) was applied as a welding technique to achieve a lap metal/polymer joint by applying the laser from the metal side. The heat was transferred from the metal layer to the polymer layer, which caused the melting and then solidifying of the polymer at the interface. The effect of three welding parameters, laser energy density, pulse duration, and welding speed, on joint force, was studied and discussed. To measure the joint force tensile shear test was conducted. Furthermore, the Taguchi method was used as a design experiment method to optimize the welding parameters by designing an orthogonal L9 matrix. The signal-to-noise ratio of each trial was calculated and plotted. The best welding parameters that gave the highest joint force were achieved. The maximum tensile force obtained was 525 N at 250 J/cm2 energy density, 15 ms pulse duration, and 20 mm/min welding speed. Finally, the comparison between the weakest and the strongest joints was carried out to show the difference between welding with the optimal parameters and any other set of parameters.