| 摘要 |
A draw stretch process is provided for shaping a workpiece initially comprising an elongated metal sheet having a pair of spaced opposite ends. The process involves placing the metal sheet in a metal forming position in a draw stretch forming machine between a bulldozer having a female forming surface and a die having a male forming surface. The sheet is positioned such that the ends thereof project laterally outwardly beyond the forming surfaces. The forming surfaces are complemental and configured to draw the metal sheet into a predetermined shape. The bulldozer is moveable relatively toward the die from a draw initiating position where it is adjacent the metal sheet to a fully closed metal sheet shaping position. The draw initiating position and the fully closed position are spaced apart a predetermined distance. The work piece is partially drawn by moving the bulldozer toward the die with the work piece therebetween from the draw initiating position to a working position located between the draw initiating position and the fully closed position. The partially drawn is stretched by pulling outwardly on the ends thereof after the bulldozer has reached its working position and the stretching is continued until any puckering or gathers in the work piece are relieved. The drawing of the work piece is completed by moving the bulldozer toward the die with the relieved work piece therebetween from the working position to the fully closed position to thereby give said workpiece its final predetermined shape. The fully shaped work piece is then stretched again by pulling outwardly on the ends thereof after the bulldozer has reached its fully closed position to thereby give the shaped work piece memory, to set its shape, and to work harden the same. The fully shaped and work hardened work piece may be formed from a corrosion resistant aluminum and used as a component in the hull of a boat.
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