Design and Manufacture of Low-Pressure Hydroforming Machine for Aluminum Tubes and Production of Rectangular Cross Section

Tube hydroforming is widely used in the production of structural parts of an Automobile. One of the characteristics of the parts produced by this process is the high strength-to-weight ratio. Low-pressure tube hydroforming is one of the proposed methods to solve tube hydroforming problems such as the need for high fluid pressure and sealing problems. The method of performing low-pressure hydroforming of the tube is like to compressing a solid object, in which, unlike high-pressure hydroforming, the upper mold is not fixed during the process and moves and presses the tube at the same time as internal pressure is applied to the tube. In this paper, the low-pressure hydroforming process of AA6063 aluminum tube is performed and the round section of the tube is transformed into a rectangular cross section by the hydroforming process. Also, the thickness distribution and the values of the radius of the formed corner are investigated under three different loading paths. The results show that by increasing the internal pressure, a smaller corner radius can be achieved but the thinning increases. Also, the maximum flat surface of the upper part is obtained when the upper mold is displaced after the internal pressure reaches its maximum value.