Improving Impact Strength in FSW of Polymeric Nanocomposites Using Stepwise Tool Design

In recent years, many studies have been conducted on process parameters of polymers friction stir welding, while material parameters are still facing serious problems especially in polymeric nanocomposites. In the present study, the impact behavior of friction stir-welded polycarbonate (PC) nanocomposites under different material and process conditions has been investigated using Taguchi approach. A stepwise tool design procedure has been carried out to enhance the welding process. The samples containing various weight percentages of alumina nanoparticles have been welded under different welding process parameters. The analysis of variance results illustrated that nanoalumina content is the most effective parameter on impact strength followed by rotational and transverse speeds. Impact strength of welded samples was conspicuously improved up to 15% by adding 2 wt% of nanoalumina compared with pure PC samples. Also increasing rotational speed and decreasing transverse speed leads to increase of impact strength. In order to optimize the process, signal-to-noise ratio analysis was performed. The results indicated that the optimum levels of input parameters that give the maximum impact strength are as following: 2 wt% of nanoalumina, 2500 rpm of rotational speed, and 8 mm/min of transverse speed which causes 26.14% improvement in impact strength of samples.