What is "cushion" on a hydraulic press?

This press has a 175 ton cushion. what is that. Just curious.

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Cushion is adjusted using Pins. ???

I'm a "chip making" machinist, don't know much about the forming end of the business.

Thank You, Randy

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Reply to
Randy
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Here's an article on the subject:

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I'm not an expert, I think that the pins limit the travel of the press so that the part in the press being drawn, doesn't tear. The article focusses on intelligent hydraulic control for deep drawing.

Reply to
Denis G.

I don't have much experience around hydraulic presses such as that one, but have much experience around mechanical presses. I'm sure that the cushion serves the same purpose on the hydraulic press as on a mechanical press.

The cushion is a pneumatic system under the bottom bed of the press and acts as a giant spring providing a reaction force to the ram's stroke. It gets it's power from general pressurized shop air feed. It consists of a series of pneumatic cylinders which act as springs supporting a steel or iron "pad" which travels up and down under the bottom press bed. By regulating the pressure in this system, the reaction force of this "spring" can be varied. The die bottom is set on the bottom press bed, the die top is set and attached to the top press bed of the ram (obviously).

The spring power of the cushion is accessed by "pins" which fit through holes in the bottom press bed and come into direct contact with the pad. The die bottom is then set and bolted to the bottom press bed. The die bottom shoe has holes which allow the cushion's pins to contact various mechanical components within the die itself and supply spring force to those components. Generally, these pins will supply the force to operate "kicker pins" that bump the web (this is the sheet metal moving through the various stations of a progressive die) up and out of preform and final form stations within the die. They also usually bump up the web guide rails (as the ram stroke recedes) which guide the stock through the die. Depending upon the part, this spring force can also be used for other functions in the stamping process. Dave

Reply to
dav1936531

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