Deformation analysis and processing parameter optimization of roller clinching

Roller clinching is a variation of conventional clinching by using rotational tool movement. The joining quality of roller clinching is significantly affected by tooling geometries and motions. Considering the formation difference of joints at different locations, this paper investigated the deformation features of roller clinching of square joints and utilized multiple linear regression analysis to optimize the processing parameters. It was found that roller geometry has significant impact on the formation of interlocks of the front/rear sides of joints, while the impact on the formation of lateral sides is less. With the increase of roller diameters, the clearance variation of front/rear sides decreases; meanwhile, the separation clearance s at the front side after forming decreases. In the study, when the roller diameter is raised from 35 to 150 mm, the connection strength increases by 44%. If the diameter difference w of rollers increases, the squeezing degree of the front side decreases, and the joining quality increases; however, if the squeezing degree of the rear side increases, then the joining quality of the rear side and s decrease. In the sample, an increase in w by 3 mm enhanced the connection strength by 9%. When the clearance difference t between the rollers increases, the capability to contain metal increases in the rear side. When t increases by 0.6 mm, the connection strength augments by 12%. The separation clearance s of the front side is greatly affected by friction μ, roller diameter, w, and draft angle γ of the lower roller, while the effect of draft angle β of the upper roller on s is small.