Investigation of Mechanical Features at Macroscopic Scale for Friction Stir Welding of Polypropylene Strengthened with 40% Glass Fiber

In this paper experimentally, the friction-stir welding of the polypropylene sheets with 40% glass fiber has been investigated. Comparison to other welding methods, the strength of the joint is the most important feature in this process. Many parameters such as tool geometry, rotational speed, linear velocity, and tilt angle are very important as input parameters in this type of welding. Therefore, in the present study, the effect of these parameters on the friction-stir welding of the polypropylene composite sheets have been extracted. Experiments are based on the Taguchi method and the orthogonal L9 array that are suitable for three-level designs. Statistical analysis have been performed as variance (ANOVA) and signal-to-noise ratio. Based on the results, the tool with a screw cone-cylindrical pin has a better apparent quality and higher tensile-shear strength. Results analyze show the rotational speed has the most significant effect on the tensile-shear strength and appearance of the weld. The joint with maximum tensile strength is obtained at rotational speed of 1000 rev/min, welding speed of 20 mm/min and tilt angle of 1 degree.