A metal 3D-printed non-assembly mandrel for profile bending

Abstract In the overall regime of production technologies, bending processes allow production of complex parts and profiles in a precise, flexible, and economical way. It is important to manufacture tools which are universally applicable and easy to manufacture, since modern industries demand flexibility in terms of larger varieties or smaller batch sizes. In the past, it was difficult and time-consuming to manufacture bending tools, especially mandrels, due to their high geometric complexity and tight assembly of swivel joints. In this paper, we present a new design approach for the bending mandrel which is suitable for metal additive manufacturing that incorporates non-assembly mechanisms of joints. The hinges are systematically developed with particular focus on achieving a minimized gap and resultant clearance. As a test case, a mandrel is 3D printed by using the laser powder bed fusion technique and successfully tested in the rotary draw bending process parameterized for narrow bends in stainless steel tubes. In the light of these results, a solution is formulated for ease in manufacturing and faster rate of tool production, in this case bending mandrel. This methodology facilitates the production of small batch sizes and large product variants in bending processes. The research presented in this paper serves as a forward step towards economical production of complex parts in a highly flexible manner.