We are using pneumatics to raise and lower our shooter; however, when we do this the cylinder cannot retract all the way. Is this a problem? Also, when testing today we noticed that the solenoid is leaking air out of one of the posts beside the inlet. Is this a result of us limiting the retraction?
Limiting the travel of a cylinder by mechanically hardstopping it is perfectly fine.
The leak is an issue, and probably unrelated.
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So I would suggest putting spares on the cylender shaft just so you have a true hard stop, for consistency sake, and use teflon tape on the post with adequate tightening
If you put too much side force on a cylinder you can harm the seal on the piston causing air to leak past it. If air is coming out the exhaust port this may be you problem.
The leak is not around the post, but rather coming from the port beside the inlet post on the solenoid.
We aren’t putting side load on the cylinder. The leak is on our solenoid. It is coming from the port beside the inlet on our solenoid. This is a picture I found. Ours seems to be leaking out of the one on the right, not the one circled.
What are spares?
It this only when the cylinder is actuated? I would suggest pumping up they system, putting the cylender into the retracted state, and waiting to see if pressure drops. I believe this port is the exhaust port
That’s an exhaust port, is it only leaking when the cylinder is in that direction? If so the cylinder is bad.
I’m not sure if it is only leaking when it is in that position. The leak is noticeable when the cylinder is extended. I’ve not noticed it when it’s retracted, but it may be leaking then as well.
We notice the leak when the cylinder is extended. If it is an exhaust port, shouldn’t it close off eventually?
Yes. This kinda sounds like a solenoid malfunction. Do you have a spare to try?
We tried 2 and both did the same thing. We are using meter valves on the cylinder if that changes anything
No leaks rarely heal themselves.
If you take the hose off of the solenoid and the air is coming out the cylinder (I bet it is) it’s a bad seal in the cylinder.
Which side of the solenoid should I take the hose loose from?
As a cylinder gets pressure applied to one side the other side exhausts the air so the piston and rod can move that direction. No air should be coming from this end of the cylinder once it’s finished it’s movement. This is the hose you need to trace and unplug. You can do it at the cylinder if it’s easier.
A lot of teams put teflon tape on the solenoid ports, this is a bad idea because the tape can break off and leave a tiny piece inside the solenoid which will cause leaks. Not sure if you guys did this, but it has burned us in the past and we no longer do it. Also, use some kind of hardstop mounted on the actuator. We have bent a lot of aluminum arms/mounting bolts by letting the bumpers or robot be the hard stop. If its retracting, you can use shaft spacers mounted on the piston
We will try it later today and see if that is the issue.
We did put teflon on the solenoid. Not sure if that’s the issue though since we tried 2 solenoids.
Teflon or PTFE or whatever tape was used isn’t really a thread sealant. It is used to lubricate the threads to allow you to tighten the tapered fittings more so the mechanical seal comes from the brass. I’m not saying that tape won’t help, but it isn’t made to seal.
Use a liquid sealant (pipe dope, loctite 545, etc) it will make you much happier and less likely to gum up the insides of you solenoids and cylinders.