By moving the forming roller, while keeping the tube stationary, the machine is also able to perform compression bending (CB), in addition to its main application of performing TRPB and RDB, as illustrated in Fig. The forming roller on such TRPB stacks is often placed on the same arm as the clamp die for RDB, thus moving tangentially to the bend die. The TRPB stack increases the capability of the equipment because it is able to create larger curves or spline-geometries. assessing springback in TRPB, and in a study regarding automatic wrinkle detection for TRPB by Simonetto et al. These combined TRPB-RDB tools have also been addressed in multiple research studies, as in the research by Ghiotti et al. For increasing the flexibility of the manufacturing equipment, many companies use multi-tool-stack tube bending machines, commonly equipped with a stack for three roller push bending (TRPB). As noted by both Kervick and Springborn, and more recently, Miller, manufacturers have largely adopted rotary draw bending (RDB) as the main process for automated manufacturing of high-precision tube bends with tight radii. Bending is an essential process for forming tubular parts.
