<p>This study investigates the effects of process parameters on the mechanical properties in the friction stir welding of 5 mm thick Polyamide 6 plates in a butt-joint configuration using tools with two different pin geometries. In addition to the primary process parameters, rotational speed and transverse speed, the impact of various tool path patterns on weldability have also been examined. The experimental design was created based on the Taguchi L9 orthogonal array, regression and variance analyses were conducted to examine the effects of process parameters on mechanical properties. Optimum process parameters were determined based on signal-to-noise ratio (SNR) evaluations. In terms of mechanical characteristics, tensile strength tests, Shore D hardness measurements, and optical microscopic imaging have been used as references. As a result, it has been observed that the cylindrical-pin tool produces joints with higher mechanical properties compared to the threaded cylindrical-pin tool in general. In terms of weld strength, a maximum joint efficiency of 41.5% has been achieved, while in terms of weld zone hardness, a level of 90% has been attained. In addition, compared to the traditionally used straight tool path, the zigzag and rectangular tool path patterns resulted in improved mechanical properties in the weld zone for both tool types.</p>