A Study of Friction Stir Welding of High Density Polyethylene Available to Purchase

Friction stir welding of high density polyethylene sheets was performed at different rotational and welding speeds and the material temperature close to the welding zone was monitored by infrared thermography and thermocouple measurements. Welding quality was evaluated by macrostructure analysis and tensile testing. Fracture surfaces of the tensile specimens were also analyzed. It was found that weld quality is highly dependent on the temperature of the material in the welding zone. For some specific welding conditions the welding process was unstable due to elevated temperatures reaching the melting point of HDPE. Instability of the welding processes was characterized by cyclic material temperatures and down forces. Decreasing the welding speed and increasing the rotational speed was found to improve weld quality.