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Hydraulic Press Pumping


#1

Hi Orchidians,

I am wondering if it makes any difference in how one pumps their
hydraulic press. If one pumps their hydraulic press up to a certain
psi in very small increments using short strokes versus
enthusiastically pumping away using full strokes does one have a
better chance of not stressing the metal as much?

Thanks, Jeanie Pratt


#2
I am wondering if it makes any difference in how one pumps their
hydraulic press. If one pumps their hydraulic press up to a
certain psi in very small increments using short strokes versus
enthusiastically pumping away using full strokes does one have a
better chance of not stressing the metal as much? 

I’m not aware of any difference. I’m not certain why there would be a
difference, in truth. Any plastic deformation of the metal induces
internal stresses, this is why metal that’s been bent will normally
distort a little when heated. The stresses are being relieved.

Paul Anderson
http://www.andersonloco.com


#3
If one pumps their hydraulic press up to a certain psi in very
small increments using short strokes versus enthusiastically
pumping away using full strokes does one have a better chance of
not stressing the metal as much? 

I seriously doubt it. Even the fastest you fan manually pump up
these presses is a pretty slow and gentle movement of the metal. To
really compare it do something, compare to a drop hammer or high
speed power press or the like. Even as fast as you can manually pump,
the metal isn’t even getting warm most of the time. It’s slow either
way.

Of much more importance would be how you design your dies and the
type of “pusher” if using urethane. If the metal is allowed, and the
die designed to allow, the metal to flow into the die during the
operation, that makes much more of a difference. You get that by
using softer rounded edges to the die depression for the initial
pressing, if you’re doing a deeper draw design, so the sheet can be
pulled over the edge into the design. Then, once mostly formed, a
second die with the desired end stage of crisp edges and details,
can be used to finalize the design. In some cases, lubrication of the
metal so it more easily “flows” over the die surface can help a lot
too.

Peter