A new technology of sheet-metal flexible-die forming using a viscoplastic pressure-carrying medium

The conventional pressure-carrying media of sheet-metal forming are solid materials (a rubber or polyurethane pad), liquid (oil and water) and gas (pressured air and expanding air). The various flexible-die forming methods using the above pressure-carrying media have a lot of different characteristics and have promoted the development of sheet metal forming technology. There are, however, a lot of disadvantages in using these pressure-carrying media. In order to explore a new pressure-carrying medium, numerous experiments have been undertaken, as a result of which a new type of pressure-carrying medium called a viscoplastic pressure-carrying medium (VPCM) has been synthesized. In this paper, a new kind of flexible-die forming technology using VPCM has been put forward and used to manufacture many different workpieces. The experimental results have shown that this kind of technology has a lot of advantages, such as a small drawing coefficient, good surface fineness, high dimensional-accuracy, and a simple and a general-service die structure. Moreover, This technology can also be used to manufacture complicated workpieces with a large degree of deformation or substantial local deformation. According to the practical uses of this technology, three sets of die are described also in this paper.