Chapter 19- Unsticking Presses Stuck on Bottom Dead Center (eChapter)

The best plan is to work carefully at all times to avoid sticking the press on bottom. Basic die setting skills such as checking die shut height with a tape measure and adjusting the press shut height on bottom to allow enough room plus a safety factor before setting the die will avoid many problems. Many presses, especially direct-drive machines used to form embossments requiring full press tonnage at the bottom of the stroke, should have the ram raised a slight amount before inching the press onto bottom dead center (BDC) to pull the die.
Some presses do not have enough torque capacity to move off BDC if stopped in that position. Many simple mistakes and oversights cause a mechanical press to become stuck on bottom. Avoiding sticking the press is the best procedure, but it may happen. Following a good sequential procedure to unstick the press is required. Shut height errors frequently result in the press becoming stuck on bottom. It is important to immediately notify supervision so qualified press and die maintenance personnel are involved in a carefully planned solution. Common causes of large overloads that cause the press to become stuck on bottom are die setting errors and foreign object damage. Should such an overload occur, the machine might have damage that may make it dangerous to operate. The press should be removed from service and thoroughly inspected for damage. The bolster and ram face should be inspected for flatness.