Vex Starstuck Pneumatic Claw

I have a question on how people are able to get a match out of this years game using a pneumatic claw. I am using 2 double acting cylinders similar to https://m.youtube.com/watch?v=yJKQKaWnA_ do u know how they are able to get so enough air for a match?? PLEASE HELP

ok, if you have a small pump, make sure you have 100psi in the tank, thats the max legal limit, with 100 psi you can get around 40 strokes until the air starts to run down, if you add rubber bands to pull together, you get 1.9x the force inwards, while still doing same force outwards. without pressure regulators im fine for a whole match. of course, not to name names but my sister team uses 110 psi and gets like 5 more strokes.
(this is not condoning cheating in any way, team 9065 is not liable for explosions of tanks, pistons or pneumatics, we do not recommend using more than 100psi at any time) ends fast talk

I have 100 psi in the air tanks. Do u have a pressure regulator on your pneumatics. Because I don’t. I think it would help. The only question I have is placement of the pneumatics cylinders. And solenoid. If ur solenoid is closer to the cylinder does it help? Also does the placement of ur points between the cylinder and claw make a difference?

I have 100 psi in the claw: the 3 things I’m not sure of is solenoid placement. Cylinder placement(points from solenoid to the claw. And pressure regulators, do they help?

Air consumption by the pneumatic cylinders is minimized by reducing the length between the solenoids and the cylinders, and regulating the working pressure to as low a level as will function. The distance between the reservior and the solenoids do not affect consumption.

If the design will allow, single acting cylinders use about half the air per complete cycle as do double acting cylinders; however, you are forced to deal with the internal spring (thus requiring more pressure). Using a double acting cylinder in a single-acting application (leaving the return port open to the atmosphere and plugging the extra solenoid port) reduces this problem.

I am using single action pistons but my question is still not answered . Does solenoid placement help and does regulators help. Even if they do I still think they would not help my problem. Also not air leaks? I don’t know the problem. The only thing I can think of is solenoid placement and pressure regulator

There is also an exhaust flow control valve which will slow down the speed of the stroke, but it has no effect on air consumption.

45 actuactions is moee than enough to get you through a game, so a pressure regulator isnt really needed, the pistons themselves should be as close to 90 degrees as possible as thats there MOST EFFICIENT. Spot. Solonoids shouls be placed as close to the piston, and minimize tube length from solonoid to piston, as you lose less air that way. Points, as far away as possible

But I can’t get the 45 actuations. Do I need2 solenoid for each air tank. Also what’s the actuation difference in number from moving the solenoid closer to the piston?

Check to see if you have any leaks. Using teflon tape on the brass fittings helps alot.

Pneumatic tips:

  1. While slightly slower opening, single action pistons nearly double the number of successful actuations.
  2. Move the solenoid as close as possible to the piston as possible; excess pneumatic tubing after the solenoid simply takes up and uses air.
  3. Pressure regulators decrease the pressure allowed past the regulator, thereby limiting the air usage. Using a pressure regulator will save air and increase the number of possible actuations. (If you choose to use a double acting cylinder, I would definitely put a pressure regulator on the “opening” solenoid, as you don’t need max air pressure to simply open the claw, thereby saving air)

@idenzer that wont actually save air

itll just lose pressure slower, because the solenoid lets out all the air on that side of itself

Do I need 2 solenoid for each tank??

no you do not, you need an individual solenoid for each piston. Essentially, you are creating one very large circuit. In order to use two tanks, you can use a t fitting between them or just tube them together. After that, just create the exact hookup that vex has on their website photo of the pneumatic 2 kit with the dual acting cylinders and it should work just fine.
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Thanks I’ll try it tomorrow

no problem, let me know if you come across any problems, id be more than happy to help.

Is it normal for the solenoid to leak only when the piston is in the open position but not in the closed position?

@skittles lover. Tighten all of your connections, they can come loose over time

It’s not normal for a solenoid to leak at all (other than exhausting the air from the pneumatic cylinder), no matter what position the actuator is in. Check that the leak is not on a screw-in fitting (make sure they are screwed in properly with teflon tape on the threads, or a hose connection (be sure the hose is cut square, clean, and pushed all the way in). Sometimes, the seal in the push-to-connect fitting fails, then you’ll need to replace the fitting. Rarely, but not impossible, a seal in the solenoid valve itself will fail. In industry, we use these solenoids for controls circuits all the time and usually get 1-2 million cycles before failure, so if this has happened, try and send it back to VEX for a replacement.

It’s a new solenoid and we checked all the fittings, none are loose, we also have had this problem in past years but never thought anything of it. It is also a slow quiet leak that only happens when the piston is in the open position (or closed depending on tubing set up). Today I will replace the fittings and see if that fixes it.