| 摘要 |
A tube bend is started by compresssion bending and continued by draw bending. Conventional bending equipment is employed with one die slightly modified so that normal machine operation causes the pressure die to initially operate in a compression bending mode and then to operate in a draw bending mode. The tube is clamped between a rotatable bend and clamp die. The pressure die presses the tube against the bend die and initially moves with the tube so as to exert little axial restraint. The pressure die is caused to exert increasing pressure upon the tube, and its motion with the tube is stopped after a short initial travel, whereupon the pressure die restrains the tube as the bend and clamp dies continue to rotate, thereby to effect a draw bending to the completion of the bend.
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