Truss Flexible Forming Mold And The Sheet Metal Stamping Key Technologies

The sheet metal forming technology is an important manufacturing technology which is widely applied in the industry of aviation, aerospace, vehicle, shipping and engineering machinery. But there are some defects existed in the sheet metal forming technology. Manufacturing cost of die is high and the die cannot be widely used. And wrinkles existed in the sheet metal forming. As the diversity and individuality of mechanical and electrical products, the batch of the sheet forming is decreasingly demanded. So it is inevitably for the forming technology to develop to the flexibility and agility. For all, it needs to research the reconfigurable principle of the die and the new technique to control the cost and time in the processing.Firstly the paper analyzed and summarized the advantages and disadvantages of domestic and foreign reconfigurable dies. Present research on wrinkling is introduced through the theoretical analysis, the experiment, the finite element simulation, thus it obtained problems existed in the sheet metal forming technology. The forming mechanism of the curved sheet was elaborated. The stress condition of spherical sheet metal part in the forming process was analyzed. Combined with the compressive buckling mechanism of plank, it studied the mechanism of sheet metal wrinkling. Then critical buckling condition on sheet metal wrinkling was obtained. The key of the paper is discussing the basic methods and ideas of suppressing wrinkling. It proposed that wrinkles can be suppressed by improving the stamping process and the structure of the die.Under the guidance of the principle of wrinkling, the paper puts forward a new kind of reconfigurable sheet metal forming die-- Poles Flexible Die. The central component of the die is a pair of matrices of flexible poles. A desired discrete die surface is constructed by changing the positions of flexible poles and changing variant heads according to the surface of sheet metal parts. Then the die is made up. At the same time, the"Multi-point Forming and Pressing"stamping process was explored. Through theoretical analysis and calculation, the stamping process combined with Poles Flexible Die can suppress wrinkling in the process of forming sheet metal effectively. Next some experiments are made to form typical curved-face sheet (spherical face sheet), space twisted sheet (leaf blade of water pump) and bidirectional formed complex curved sheet (saddle-shaped board). Experiments verify that Poles Flexible Die has good capability of reconfiguration. It shows the forming properties of the die and the effect of suppressing wrinkling in the process of forming sheet metal parts.Poles Flexible Die integrates forming sheet metal, holding blank and discharging. It has many advantages such as reconfiguration, low cost, high efficiency and high forming precision etc. Combining the"Multi-point Forming and Pressing"stamping process and the die can suppress wrinkling occurred in the common die. It is firmly believed that the structure of the die will improve continually. The die has obvious advantages in middle-small batch of curved-surface sheet forming. It can be widely used.