Process optimization in friction lap welding technique for joining SS - Nylon plate materials.

Friction lap welding (FLW) becomes increasingly popular as relevant technology for joining materials that are difficult to weld or even unweldable such as dissimilar materials. In this work, stainless steel (SS) AISI 304 and nylon 6 plates were joined by melt-filling of nylon to the previously prepared circular holes in SS plates through the tool friction along the clamped-material surface. The dual passes tool travel was conducted in a constant rotational and traverse speed of 2000 rpm and 20 mm/min respectively to accommodate the welding joint in the variation of hole diameter (4, 5, and 6 mm), tool diameter (10, 12, and 14 mm), and tool tilt angle (0, 2, and 4°). These process variations were carried out to investigate and optimize the joint shear strength using Taguchi method, and the contribution of each parameter was analyzed using ANOVA. The results indicated that the amount of heat generated during friction plays an important role to characterize the nylon pins resulted in SS holes and thus affects the shear strength. The optimum parameter combination was found at the hole diameter, tool diameter, and tilt angle of 4 mm, 14 mm, and 2° respectively. It is also clear that the tool tilt angle showed the highest contribution in determining the shear strength among others with 23.80 %. The robust design indicated the signal-to-noise (S/N) ratio value of 26.44 with the gain of 4.06 from its initial design. [ABSTRACT FROM AUTHOR]