Pneumatic Press feasable?

I was digging through that stuff in my back yard and ran across a pallet load of air cylinders. Some big ones, tiny ones, just a bunch of them.

Ive got a 15ton hydraulic press frame, with no press, so was wondering if its feasable to use an air cylinder instead of a hydraulic one.

Ive got a 3x 3 1/4 (3" stoke), with a 1" ram, threaded on the end for accesories, that would bolt up to the top rails of the frame pretty easily. How much "power" could I expect to put out at 90psi? This is something Ive never had to futz with before.

How do you slow down the ram travel so it doesnt Slam out of the cylinder, but gets the full pressure built up? One would assume a valve on the opposite end of the cylinder, but??

Any advise, or alternative suggestions would be appreciated.

Gunner

"The people who believe that, as a result of industrial development, life is about to become a hell, or may be one already, are guilty, at least, of sloppy pronouncements. On page 8 of Earth in the Balance, Al Gore claims that his study of the arms race gave him "a deeper appreciation for the most horrifying fact in all our lives: civilization is now capable of destroying itself."

In the first place, the most horrifying fact in many of our lives is that our ex-spouse has gotten ahold of our ATM card. And civilization has always been able to destroy itself. The Greeks of ancient Athens, who had a civilization remarkable for lack of technological progress during its period of greatest knowledge and power, managed to destroy themselves just fine." -- P.J. O'Rourke, All the trouble in the world. The lighter side of famine, pestilence, destruction and death.

Reply to
Gunner
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pi* raduis*radius gives you the cylinder area. (3.25/2)*(3.25/2)*3.14159=

8.3 sq in.

90 lb/sq in* 8.3 sq in = 750 lbs.

Not much for a press. Might work OK for sheet metal. Now use hydraulic at

2000+ psi and you got something.

As to slowing down an air cylinder, a restrictor valve on the exhaust is standard, or even on both sides. You'll want to power it back up

-- An apple a day keeps the doctor away. Two apples a day gets the doctor's OK. Five apples a day makes you a fruit grower, like me.

Karl Townsend in beautiful Dassel,MN

Reply to
Karl Townsend
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I would not use air for a press. It compesses, so you are working with a POWERFUL spring. If anything goes wrong peices of press and/or work will be flying everywhere. Some air cyls are also rated for liquid (hydraulic) use.

Reply to
clare

the main trouble with air, is its ON or OFF. with a hydralic cylinder, you can get all the places in between as well.

Air pressure (90 psi)*area of cylinder base, 3.25"diameter (Pi*r^2=8.295768 square inches)=about 750 pounds of force. Not enough to do anything useful, press wise, but plently enough to squash your fingers. Again, when you puss the button, the pnematic cylinder goes ALL the way in the direction you specify.

Genernally, the ram keeps travelling till it meets some resistance. Most of the time, this is provided by the far end of the cylinder, or whatever the end of the ram is connected to.

Get a bottle jack. I would even use a large screw setup in preference to the air cylinder.

Having sad that, I have used an air over hydraulic porta power setup that was quite useful. Used air power to move hydraulic fluid, controlled with a foot switch.

Reply to
Wayne Bengtsson

Hey, Gunner, Seeing those responses makes me think it would make a dandy crusher for aluminum cans etc.

BTW, What have you got there? A junk....excuse me...a recycling yard?

Reply to
BigJoe

This was also mentioned by someone this morning and it is a "deal killer". Stick with hydralics, they can be very cheap and (in this application) worlds safer!

Vaughn

Reply to
Vaughn

[Flow limiters mentioned elsewhere in the thread.] I have used a pneumatic toggle press. Very speedy, and with an adjustable amount of force available by adjusting toggle geometry and/or air pressure. Used it to press in PEM sheetmetal inserts. Can be very fast if you need it, can be run slow with a flow control. Ours had a rocker foot pedal with a proportioning valve (up/down stroke) that allowed 'easing' it down with a bit of practice.

Mechanism worked like a nearly straight elbow (your shoulder fixed, your hand applies the desired output force) - air cylinder applied force to the joint to force it completely straight. Force and stroke were adjusted by varying the length of the 'forearm' link via turnbuckle. Could generate some very serious force. One unfortunate user nearly pinched the tip of his thumb off in it. Would have crushed the bone but thankfully just caught a corner of it.

It was fast and easy to configure with the turnbuckle and pressure regulator setting, as well as much faster operation than an hydraulic press. Disadvantage was that force is not constant through the stroke, but it could sometimes be used to advantage.

HTH,

StaticsJason

Reply to
Statics

I've made several pneumatic presses for an operation where we needed to apply force over various sized plates sticking them together with double sided tape. Largest was about 1 sq. ft.

I made sure to use interlocked switches so the operator HAD to use both hands on the switches to operate the press. A small PLC provided the logic programmability as well as the timing functions so the user could always get the same dwell times. In an industrial application, you ALWAYS need to pay attention to safety. People will do the darnest things to bypass switches intended to protect against momentary lapses in attention. Even in a home shop, distractions will trap someone too familiar with his equipment to "need" those silly safety procedures.

I'm reminded of the skydiver's mantra:

"The Earth is very patient"

Earle Rich Mont Vernon, NH

Reply to
ERich10983

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