Process Parameters Optimization for Friction Stir Lap Welding of Polypropylene Composite Using Taguchi Method

Friction stir welding is now being actively considered for welding polymers and composites. In this article, friction stir welding has been used for lap joining polypropylene composite plates having 20 wt% glass fiber. The effects of important process parameters such as tool rotational speed, welding speed, and tilt angle on tensile shear strength were investigated experimentally. Taguchi method was initially used to plan a minimumnumber of experiments. A L9 orthogonal array (three factors at three levels) was employed to evaluate effects of rotational speed (800, 1000 and 1250 rev/min), welding speed (16, 20 and 25 mm/min) and tilt angle (0, 1 and 2 degree) on tensile shear strength of the joint. Analysis of variance was applied to calculate sum of square, variance, ratio of factor variance to error variance and contribution percentage of each factor on response. The results showed that rotational speed, welding speed and tilt angle were significant factors respectively. It was also found that tensile shear strength was maximum when rotational speed, welding speed and tilt angle were assigned as 1000 rev/min, 20 mm/min and 1 degree, respectively.

Keywords:

friction stir welding , polypropylene composite , tensile shear strength , Taguchi method , Analysis of Variance