My pneumatic cylinder needs to push down 25% of its capacity at the start and then push with 100%. 2

[Imposter666]

I have an SMC cylinder with 50mm Dia operating at 60psi. I need to design a pneumatic circuit that would enable the cylinder to push with 10-25% its capacity (I need a pressure regulator to adjust as needed) at the start. Then once the part is lifted of the table, I need the cylinder to push down with 100% of its capacity. I will have a part present sensor to communicate to the SMC manifold/valve that it is time to apply the full pressure. What kind of 5/3 valve and pneumatic circuit would I need for this?

 

[LittleInch]

I would say one valve with a supply pressure of 25% of the second valve.

The first will simply close up once the higher pressure supply is activated.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[BrianPetersen]

ASSuming that you also need it to retract, you need two directional valves in sequence. The first selects between line pressure (port A) and regulated-down pressure (port B) with the result to the P port. The second takes P and distributes that via its A and B ports to both ends of the cylinder as usual.

 

[TugboatEng]

If you apply 75-90% pressure to the release side of the cylinder then you simply need to vent the release to gain full force. After the operation re-apply the 75-90% to retract the cylinder.

 

[srini1785]

Two solutions come to my mind.

1. Use a 5/2 way valve with port 1 connected to a I/P converter. You can set the output pressure using 0-10V /4-20mA signal.
2. Use two 3/2 way valves to connect to port 1 of a 5/2 way valves. These two 3/2 way valves can be connected to different pressures to their port 1. In this way you can change the pressure in Port 1 of the 5/2 way valve.

 

[PNachtwey]

How precise does this need to be?
What to you mean by capacity? When you use the word push I think of force.
Are you really trying to control force? In this case force = pressure1*area1-pressure0*area0.
Even if you vent the exhausting side there will still be atmospheric pressure opposing the side that is pushing.
What mass is being lifted?
Controlling one 5/2 way valve is much easier than controlling two 3/2 way valves if precision is required.

I hate small pneumatic projects like this. What happens is the air gets dirty and starts to gum up the works.
Seal friction can be a problem. Usually the cylinder starts to suffer from slip/stick or Stribeck friction.

Can it be done? Yes. But I would consider using a small electric motor.

Peter Nachtwey
Delta Computer Systems

http://www.deltamotion.com

http://forum.deltamotion.com/

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