pneumatics for featherweight

[Liftoff]

You got a point there, to counter this some rams incorporate cushions in the endcap...on mine I placed a rubber disc on the piston so the impact will be dampened

http://m.machinedesign.com/pneumatic...atic-cylinders

[ChrisKazoo]

I have drilled 4mm holes in the top of the ram since I made that video. Where can I get my hands on these rubber cushions Chris?

[Liftoff]

I doubt you'll find any off the shelf for your ram, there are kits you can buy, but only for branded parts eg festo, parker, smc etc. On mine I used a piece of rubber, punched it into a disk and glued it to the piston. You could do the same, take the circlip off and remove the top cap, put a piece of rubber say 5mm thick and you're good to go.

[Rahulvyas]

Is my 8mm pipe fine? Or do I need bigger?
I bought a 50mmx50mm stroke and bore cylinder which didnt have smooth action. Can it be fixed?
When I supply co2 into it, the piston doesnt have a sudden action like all the videos I have watched of you guys.

Also, where do I connect the QEV in double acting cylinder? Will that help me in anyway?

[Liftoff]

Rahu your 8mm pipe should be ok
What's the port size of the cylinder you bought, and at what pressure are you operating?

[Rahulvyas]

I am operating at about 100-110psi
I am not using buffer tank.
Port size I am not sure, its about 6mm I guess

[Liftoff]

Then you got your answer... not using a buffer means you're relying on the regulator for flow, the regulator orifice is very small and flow is low, you got yourself a lifter not a flipper.
You need a buffer tank to achieve anything close to what you see on videos you've seen.
A better idea would be to enlarge the port orifice on the cylinder and install a QEV on the inlet...all this has been discussed at length on various threads...and I believe on this thread as well...on the first pages there's a schematic

[Rahulvyas]

Okay I will see that Thanks,
The schematic was for single acting, so I was a bit confused with the connection of QEV

[leorcc]

Your issue is indeed flow. You need enough of a reserve of pressurized gas to be able to get the ram filled quickly. The best way to achieve this is with a buffertank between the regulator and the valve. Rule of thumb, the volume of the buffertank should be at least 3 times the volume of the ram. But even if it is smaller, it all helps.

[Rahulvyas]

I am planning to use a co2 catridge 30g-50g ( quite small) , should do the work as we are not storing 50 bar pressure into it directly, its just a small co2 collector, right?