2015 Volume 33 Issue 1 Pages 89-97
In this study, new butt welding technique was proposed to join the polymeric materials, in which the polymeric material is softened by the heated tool due to the Joule's effect heating of the electric current flow through the tool, and the coalescence of material is done by the stirring action due to the tool rotation. 3 mm thick Polycarbonate (PC) sheets were joined in various joining conditions, from which joining mechanism, mechanical properties of joints and process parameters affecting joint performance were investigated. In the experiments, in-situ observation with CCD camera and material temperature measurement during process, as well as the observation of surface appearance and cross-section of the joint and tensile test were performed for these purposes.
It was shown from the in-situ observation and material temperature measurement that the molten and softened region is formed around the weld tool. It was also shown that sufficient heat input was required to form the sound joints with acceptable performance, which depended upon the joining speed and amount of electric current flow through the tool. The observation of joint appearance and cross-section revealed that the joint with comparable thickness to base material was obtained under the condition of revolution pitch below 0.08 mm, defined by the ratio of joining speed to tool rotation. It is noticed that the joint obtained from the proper conditions have same mechanical properties as the base material, and that the process parameters of this method were tool rotation speed, welding speed and amount of electric current. These results suggest proposed method is useful for joining the polymeric materials.
