Effect of tool geometry variations on weld bead structure and mechanical properties of friction stir welding of dissimilar material Acrylonitrile Butadiene Styrene and polystyrene sheets thermoplastics

Abstract

Acrylonitrile Butadiene Styrene (ABS) and Polystyrene Sheets (PS) are versatile thermoplastics that are likely to be used in engineering thermoplastics commonly employed in automotive interior components, consumer electronics housings, household and medical products, and lightweight packaging structures. ABS is durable and resistant to impact, while PS is stiff. The present study investigates the effect of different tool pin geometries and process parameters on the weld bead structure and mechanical properties of friction stir-welded (FSWed) dissimilar thermoplastics, ABS, and PS. Both tool pin profiles, namely Threaded cylindrical (TC) and threaded triangular (TT), were made with the same shoulder diameters (21 mm) and pin lengths (3.7 mm) and joint under varying process parameters, including traverse speeds (9, 18, 27 mm/min) and rotating speeds (800, 900, 1100 rpm) is used to join ABS & PS. With a maximum UTS of 24.5 MPa, Shore D hardness of 83.6, and elongation of 5% at 900 rpm and 18 mm/min, the TC tool continuously outperformed the TT tool. Because TT tools required less heat and churning, the weld appeared smoother but had lower mechanical strength (higher strength was found at 18.98 MPa at 900 rpm and 27 mm/min). The findings demonstrate that TC geometry offers better material flow and bonding, making it more suitable for thermoplastic joints with high strength.