That’s a very good question. You will not see much, if any, change
in force exerted upon your workpiece by using an air-hydraulic pump,
but it will make it easier and faster to cycle your press. Whether
you pump by hand, or with air or electric hydraulic pumps, they all
produce the same maximum fluid pressure, about 10,000 psi.
If you need more force applied to your workpiece you can do one of
two things, get a press frame and ram rated for higher force, or
confine your pressing to smaller areas.
The force applied to your workpiece is directly related to surface
area. Your press is capable of 20 tons per square inch. If your
workpiece is 4 square inches then you can only exert a maximum of 5
tons per square inch. The converse of this is that with the same 20
ton press you can also exert 80 tons of force upon a dime sized
workpiece. This amount of force is enough to be very dangerous
because a lot of materials break or shatter with less force than 80
tons per square inch.
If you are embossing, try using a smaller piece of urethane, cut a
1" square of 1/16" thick 95 durometer, and press your workpiece
multiple times moving the 1" square around the workpiece. By
observing the force needed per-square-inch to achieve the desired
results you can then calculate if you need a press with more
Air-hydraulic pumps are relatively inexpensive, but they are noisy
and require a lot of air pressure and volume. When you factor in an
air compressor the cost goes up considerably. Electric pumps are more
expensive but are quiet and easy to maintain. Either of these
options will give you faster cycle times but no more force is exerted
on your piece. The drawback with either of these two options is that
they are more difficult to control, things move faster, and you’ll
have less sensitivity to the pressing of your work.
I hope this helps,
or an electric pump, or a manual pump.
The force available is whatever your ram is rated at, how you move
the hydraulic fluid is