Experimental and Numerical Investigation of Metal Tubes Forming with a Novel Reconfigurable Hydroforming Die based on Multi Point Forming (MPF)

Tube multi-point hydroforming is a new flexible forming technology for manufacturing of various tubular parts that presented and investigated in this paper for first time in the world. In this process¡ one die is enough to deform tubes to different shapes by utilizing high pressure fluid. In conventional hydroforming¡ it is necessary to manufacture different dies for producing different geometrical parts. This requires higher process time and cost. In present novel¡ tube multi-point hydroforming is investigated via FE simulation and experiments. In this process a new die based on multi point forming were designed and manufactured. Due to good formability of brass 70/30¡ a bulged tube and a rectangular tabular cross section of brass with initial thickness of 2mm are produced by applying this die to the process. The main difference between multi-point die and conventional dies is substituting the rigid surface by wide spaced pins. By adjusting the pins height¡ different tubular cross sections could be produced. This process is simulated and verified experimentally and defects are predicted. In order to decrease these defects an elastic layer of polyurethane is used. According to the simulation¡ maximum decreases in thickness are 11% and 17% for the bulged and rectangular cross section samples. These results are matched with the experiment.