Push-bending method development of thin-walled tube with relative bending radius of 1 using sectional elastomers as mandrel

It is important for the thin-walled tube with relative bending radius of 1 to be bent with mandrel in order to avoid the defects such as wrinkling and cross-section distortion. In this paper, a novel push-bending method using sectional elastomers as mandrel was proposed to form the 5A02 thin-walled aluminum alloy tube with relative bending radius of 1 and 90° bending angle. Cylindrical polyurethane rubber (CPR) with shore hardness of 80A was chosen as the sectional elastomers. The influence of diameter ( d ), thickness ( t ), total length ( L ), and arrangement of CPR filler on the push-bending deformation of tube was first explored by means of simulations and experiments. According to the simulation results, 5A02 thin-walled aluminum alloy tube with relative bending radius of 1 was successfully fabricated with the sectional CPR as mandrel in the self-developed equipment of push-bending. The experimental results were in good agreement with the simulation results. The optimum parameters of CPR filler in push-bending process were obtained as follows: 37 mm diameter, a piece of CPR with 20 mm thickness contacted with the punch, and other 12 pieces of CPR with 10 mm thickness.