Submerged ultrasonic welding of fused filament fabricated short carbon-fibre-reinforced polyamide plates with energy directors

Abstract

Ultrasonic welding (USW) is an extensively used joining technique employed in various industries such as automotive, aeronautics, packaging, and others, for joining thermoplastic and thermoplastic composites. The strength of USW can be further enhanced through preferential heating with the induction of energy directors (EDs). The present study investigates water-submerged ultrasonic welding (S-USW) using three different ED designs to join 20% short carbon fibre-reinforced polyamide, commonly referred to as CF/PA. This approach improves weld strength and mitigates material degradation caused by rapid heating, a common issue encountered during USW. The results indicate that the submerged ultrasonic welded (S-USWed) specimen with a semi-circular ED exhibits the highest weld strength, that is, 16.4 MPa compared to specimens welded via conventional USW technique using rectangular and triangular EDs achieving weld strength of 14.69 and 14.3 MPa.