Pneumatics

I am putting together a base kit of pneumatic components for our team. I would like to standardize on a valve/manifold supplier.

Can you recommend a valve/manifold combination?

Can you recommend a valve from the same supplier as above that operates without a manifold?

I am also purchasing cylinders. We have used Clippard in the past, but it would be nice If I could purchase these from automation direct or McMaster or the valve/manifold vendor. Does anyone have experience with cylinders from these suppliers? If so, what family do you recommend?

We have had good experience with the Nitra regulators and gauges from Automation Direct.

1 Like

I am with AutomationDirect so am a bit biased … but you can find everything you need here: https://www.automationdirect.com/adc/shopping/catalog/pneumatic_components
With free 2-day shipping to the US and Canada for orders over $49. If you haven’t used the KOP Voucher yet, the deadline has been extended to the end of the year. Please use it to get free stuff - the more teams use, the more we can request next year.

14 Likes

+1 for Automation Direct! Great quality and great prices, for pneumatics and also a wide assortment of sensors, cables, and even colored zip-ties (pack of 100 for as low as $1)! Automation Direct rules!

6 Likes

+2 for Automation Direct. We use mostly the AVS-5 series valves. They can be mounted on a manifold or not. Just be sure to get the ones with 1/8 NPT ports. Their web catalog is easy to search, easy to order First size quantities, and fast shipping. (Free shipping 2 day shipping for orders over $50.

5 Likes

I put together this spreadsheet of Festo valves and regulators that are relevant to the FRC market.

There are tabs for valves that can be used with or without a manifold block, and valves that must be used with a manifold.

Festo also has cylinders, I haven’t come up with a spreadsheet detailing options yet, but the DPRA line is probably the most relevant to the FRC space in terms of options and cost. We’ve also got pancake-style cylinders commonly used in shifting gearboxes or other short-stroke applications.

1 Like

What 4130 uses is festo for all valves, and AutomationDirect for all cylinders. Festo’s valves with the FRC discount is like impossible to beat, and automation direct cylinders are awesome and cheaper then the other options.

1 Like

Your spreadsheet is great. You have fittings for 4mm, 6mm and 1/4" tube. What do you actually use and why? Are the 6mm/1/4" interchangeable using 1/4" od tubing?

I suspect the 4mm is for lower required flow on long runs to lower weight and ease routing. How has this worked for you?

The quick connects have R1/8 in notes and the manifold has a G1/8 for threads. Are these the same?

How do I buy these parts?

How do I get the discounted pricing nick4130 mentions? (note, I sent an email to our lead mentor regarding any Festo vouchers. )

I’m coming up on 2 years at this job, and only one robot I’ve been involved with in that time has actually used pneumatics. It used a majority of 4mm tube, with a couple 6mm runs for the most time-sensitive actuation. I don’t believe any rigorous testing was done to compare timing, but I suspect the gain was minimal, in the scale of tenths of a second (if that) compared to even a full second. With other feedback I’ve seen from others on the ease of routing, and seeing what’s often used in industrial settings, I’d feel pretty comfortable sticking to 4mm as a general recommendation at this scale.

6mm and 1/4" tubing and fittings are not interchangeable. 4mm and 5/32" tubing and fittings are, as 4mm is nominally ~.001" larger than 5/32".

R1/8 male threaded pieces will fit into G1/8 female threaded pieces because they share a major diameter, but the R thread is tapered where the G thread is parallel. There’s a bit more info in this guide I put together. You’ll need some sort of thread sealant for tapered -> parallel connections, but the R thread fittings linked in my sheet should come pre-coated. If you’re going to disassemble and re-use the fittings, re-taping or coating them is probably a good idea.

To buy Festo components, I’d recommend calling the contact number on this page to register an account and get setup with the FRC discount structure, then you can place orders using our online shop or via the customer contact center. I actually haven’t tried to set up an account using only the website, and I think you’ll still have to call for the discounting, but if you run into any issues feel free to shoot me a PM and I’ll do what I can to help.

I don’t think we have any vouchers out there, but our VUVG-LK valves (linked in the spreadsheet) have been available via FIRST Choice for a few years now.

Can someone clarify, when I use a two position single solenoid versus a two position double solenoid?

Do I pair the single solenoid with a spring return cylinder and the two position double solenoid with a double acting cylinder or are these two items separate concepts?

If these are separate concepts please explain the four use scenarios.

You got it right, double solenoids for double acting pistons, single solenoids for spring return pistons.

AriMB gets it right

Double-acting pneumatic cylinders have two inputs, and use pressure to shift the piston in both directions. Single-acting spring-return cylinders have one input and use pressure to shift in one direction and a spring to shift in the other direction when pressure is released.

There are two different concepts with solenoid valves: the number of electrical solenoids and the number of output ports.

A double solenoid valve has two electrical solenoids. When one is fired pressure is directed to one pneumatic output, when the other is fired it is shifted to the other output. A single solenoid valve has one electrical solenoid. When it is energized pressure is sent to one output port, and when it is not energized a spring send the pressure to the other output. Both single and double solenoid valves commonly used in FRC have one input and two output ports.

There are also solenoids with one input and one output. You can think of these like a controllable valve: either letting air through or not. These are much less common on FRC robots.

You can use any type of solenoid valve with any type of cylinder. Although if you’re using single-output solenoid valves with double-acting cylinders you’ll need two, one for each cylinder input. And if you’re using double-output solenoid valves with single-acting cylinders you’ll need to plug one of the outputs of the solenoid valve.

 

This is not correct. Read above.

4 Likes

If you’re willing to take a deep dive, there is a lot of money (or fake BOM money) to be saved by shopping (or just browsing) on Ali Express.

6 Likes

A great overview on the difference in behavior, but I don’t think it answered OP’s query:

I’ll split the two, but here are the applications:

If your application requires full or nearly full force in both directions, use double-acting cylinders. If it requires significantly higher force in one direction than the other, consider single-acting cylinders, with the action being in the direction requiring the larger force. Doing this can save a lot of air. Another consideration is what happens if your pneumatic system springs a major leak; a single acting cylinder will have a well-defined action; if you’re big on fail-safe, single action may be the way to go, even if it means providing more return spring than the cylinder provides.
Note also that a double-acting cylinder can be used as a single-acting cylinder with the addition of an external spring or counter-weight. This isn’t the neatest solution for today’s problem, but it may be a better use of funding when considering re-use of components (I have absolutely done this, and would do so again, as that cylinder from 2016 was re-used in the 2018 post-season to great effect!).

If your device spends most of its time in one state, a single solenoid valve is likely a good fit. You will only need to provide current for the “unusual” state. If your device spends roughly equal times in each state, especially if the transitions are more than a very few seconds apart, a double solenoid valve is likely the right answer. (Just make sure that the solenoid is turned off after the transition has taken place!) Not as big a deal today as before the PCM, but there is always the limitation of how many pneumatics channels you are using that may push you to single solenoid valves.

On the crossover, if using a double-acting cylinder, a five port solenoid valve is required (or two three port valves, but one of them is likely to be misused in this case). If using a single-acting cylinder, a three-port solenoid is adequate, but I’d rather order a five port solenoid and plug the extra holes because it’s more likely to be useful in a future year.

1 Like

Great list! I’ll add one more: if you need the state of the cylinder to stay in a different position at the end of the match than at the start of the match, or you want the cylinder to never move when the robot is disabled, you need to use a double solenoid. And the converse is true for single solenoids (e.g. if you want to always be in/return to a certain state when the robot is disabled).

The reason for this is that double solenoids have “memory” (they latch in the last position unless explicitly commanded to change state, and do not change state when the robot is disabled) versus single solenoids (when the robot is disabled, they always return to the A position).

1 Like

17 posts were split to a new topic: Split Thread: Closed Center Valve Applications & Plumbing

This brief overview of pneumatic valve schematic symbols may be helpful. Check out the Interactive Pneumatic Circuit Symbols link on that page as well.

As Karthik said there are cheap solenoids from China. We have been using some forms of them since 2016.

The Spectrum Advanced Pneumatics Guide, documents some of how we setup our pneumatics system most years.

2 Likes