Feasibility study of cam-shaped tube production using elastomeric tool versus fluid forming method

Nowadays, the flexible-die forming (FDF) technology is widely used for manufacturing the complex tubular components in industries. In this present study, the forming feasibility of a cam-shaped 304 stainless steel tube by using an elastomeric tool has been investigated, and the results have been compared with hydroforming method as well. In bulging by using a polyurethane rod, the tube was placed into the desired location of the die cavity and formed by the pressure exerted inside the tube through the flexible interface. The 3D finite element simulation of the bulging process was carried out based on arbitrary Lagrangian-Eulerian (ALE) adaptive meshing for the rubber tool and forming limit diagram damage criteria assigned to the seam-welded tube. The experimental apparatuses have been prepared for both processes. Furthermore, the tube was meshed by circular grids, and strain distribution was measured after forming. Experimental and numerical implementation showed that unlike using the elastomeric tool, in the hydro-bulging process of the cam-shaped tube, the mandatory axial feeding of the tube is necessary to fabricate a defect-free part. The results showed that in terms of tube deformability, the rubber pad forming can compete with fluid forming if the process variables are set properly. Of course, by using fluid bulging medium versus solid elastomeric rod, it is far easier to fill the small radius of the die.