摘要 |
An apparatus and method relating to an improved die for homogeneously stretch forming sheet metal in standard sized presses without also drawing the sheet metal. The die is comprised of complementary male and female die halves moveable between open and closed positions, and a blank holder member moveable between open and closed positions relative to the female die half. A pair of grippers having mutually facing surfaces is carried by the female die half and the blank holder member. One of the gripper surfaces defines exactly two rectangular shaped beads which extend entirely around the circumference of the male and female die halves, while the other of the gripper surfaces is flat. The beads are equally spaced apart along their lengths and each includes a pair of relatively sharp edges for biting into the sheet metal.
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