Thread: Learning about pneumatic controls

Hi, I'm looking for courses or other resources for learning how to design and build pneumatic controlled machinery. I've looked at several local community colleges around here (I'm in Orange County, California) and none of them have any courses that are related.

I am in a business that works with a lot of electrical wire and cable - we do a lot of cutting, stripping, bundling, etc. Although we own machines that do very specific things (like stripping the end of a wire), I would like to be able to design/build machines to handle special processes or combinations of processes. And sometimes it's not enough to use electrical solenoids or servos - air power does become useful in certain applications that require a lot of force.

Can anyone make recommendations where I can look for courses?
Any specific books or other literature you've found to be really useful?
Seminars given by pneumatics vendors?
Online resources?

Thanks in advance!
David

Hi David

I am like you, started out knowing zero point zero about components and such. If you are looking for someone close to you that you can see and get help on things quickly, I would recommend Mag Troll in Long Beach. Tell them what you are up too and they will help. My sales guy Norm was fantastic at holding my hand down the path.

Mag-Trol Long Beach Home Page

Just remember you get what you pay for. If you want them to give you the help, they are expecting you to buy from them.

I taught courses in fluid power for several years. Three training books I found useful were from the following:

TSI (Tool Systems Inc)

ARO Fluid Power

Parker Fluid Power

The copies I have are 8-10 years old and may no longer be available. However, a cursory google for "pneumatic training" comes up with several online courses and training materials.

I wrote a pneumatics training course for a local company about ten years ago. It was based on (plagiarized from) the above mentioned books. I would gladly send you an electronic copy but the file is buried away in some arcane format - who knows where.

In my experience, training materials developed by professional educators are worthless, and most cost money. The best materials come from industry and are free. My guess is they are all online these days.

Doug

"pneumatic Control" by your verbage sounds like you simply mean using an air cyl for linear and possibly an air motor for rotational movement.

IMO "Control" would have been more in line with "Air Logic". This would be the air/mechanical version of a PLC and/or relay logic. (read explosion proof)

I started out with air logic as PLC was still very expensive as far as I knew at that time (1990) and the ARO factory is only 10 miles away.


No idea what there is to learn about an air cyl?
Pi x Rad Sqr x line pressure = force
For return stroke you need to remember to subtract the rod value.

Now there ARE some multiple piston cyls. Never used one, and they are expensive, but they can get you more force in a small cyl for limited space. Stroke is prolly semi limited tho?


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Think Snow Eh!
Ox

There are some ebooks on the hydraulics-pneumatics website. I believe they cover about 95% of what a beginner needs to know.

Fluid Power Ebook Edition 1

Also I would look into getting the demo copy of Festo fluid-sim, where you can run animations of various air systems. It's pretty good for illustrating the concepts of flow & pressure.

one idea is to buy a bunch of valves, fittings air cylinders etc on ebay and just experiment. this stuff is really easy to work with and you will learn allot just messing around.

I'll second Doug's note about the comparison of 'store bought' vs. value of "Industry-free" training documentation. I write all training materials for the classes I teach. The most extensive materials were for WABCO 26C/L compatibility airbrake control systems and electronic-over-air and electronic-over-hydraulic for rail equipment. In fluid power controls, you're using characteristics of the fluid (either liquid or gas) to operate analog and binary control elements to make operating sequences and decisions. In today's world of software/electronic process automation, things are easy to implement with incredible simplicity at the OTHER end (solenoids controlling air to cylinders, and regulators and leverage ratios limiting pressures, orifices controlling speeds)... using actual controls beyond that are pretty uneconomical.

By your description, it doesn't sound like as much of a pneumatic CONTROLS system, as you have automation that would be well-satisfied by pneumatic automation, using some OTHER sort of controls.

In any event, the elements of fluid control (liquid or hydraulic) are very closely related, with just a few considerations specific to the difference between liquids and gases, and I'll point the most critical ones out:

Liquids are compressible, gases are not.
Systems filled with liquid are called hydraulic.
Systems filled with gases are called pneumatic.

Liquids can become saturated with air... this makes them pneumatic, rather than hydraulic.
Gases can become saturated with liquid... this makes them hydraulic, rather than pneumatic.

Instance of either can cause a drastic change in how a system performs and reacts, and frequently drastic damage.

Hydraulic and pneumatic systems have a variety of filtration and settling systems incorporated into the design to prevent the above, and many of those characteristics are inherent in the design, but not readily apparent to the observer or technician.

Oftentimes, the key element of proper system performance is time, temperature, and gravity.

Peas are Vegatables, which are on the Table. (P*V)/T (where T is expressed in degrees Kelvin). (Boyle's Law... when expanded, is referred to as Combined Gas Law).

Heat and cold both have considerable effect on the performance of fluid power systems. Heating and chilling are natural effects of the fluid power process, as well as inherent in the environment of operation, so always respect Peas and Vegetables on the Table.

As far as simple gadget and experimentation goes, if you have some stuff, some basic math skills, and a source of compressed air, you can make some incredible things happen. One of my favorite projects of youth, was setting up an air cylinder to operate the lever of a shotgun shell reloading machine... A buddy and I found that after four hours of crunching out shells (and we shot lots of clay pigeons), that neither he nor I could obtain the same crimp forces we did on the initial hour or so... and the shell performance degraded. So I rigged up an air cylinder to a foot-controlled pushbutton valve, and installed an air-pressure regulator in the supply line to limit max cylinder pressure. We put a return-spring on the ram to bring it back, and I put a needle-valve in the cylinder's supply line to control speed of the handle... and after that, we just dialed up the regulator to the desired crimping force, and stomped on the button... same crimp force for hours on end.

Originally Posted by DaveKamp

In any event, the elements of fluid control (liquid or hydraulic) are very closely related, with just a few considerations specific to the difference between liquids and gases, and I'll point the most critical ones out:

Liquids are compressible, gases are not.
Systems filled with liquid are called hydraulic.
Systems filled with gases are called pneumatic.

Uhhh.....

Originally Posted by DaveKamp

Liquids can become saturated with air... this makes them pneumatic, rather than hydraulic.
Gases can become saturated with liquid... this makes them hydraulic, rather than pneumatic.

I'm thinkin' that there must be something that fits in the middle?




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Think Snow Eh!
Ox

Originally Posted by Ox

Uhhh.....

I'm thinkin' that there must be something that fits in the middle?




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Think Snow Eh!
Ox

Well Ox....
skidoo ( Kayaba) had the emulsified oil shocks...
They had the oil in the shocks emulsified (frothed, as I understand) with trapped bubbles so that the performance would not degrade so much...

Now if Anybody should have known about skidoo stuff it would have been....

....well _ let me tell yuh....


I don't ride the moguls. I gave that up 15 yrs ago, before or just as those were comming out.

I run cheap std hydro's on my ride. I am WAY more likely to rip a shock apart b/c of landmines than I am to come home with a bad back doo to moguls. Those trails have cooties don't'cha know.

I even go so far as to carry a spare front shock on the sled! (with spare rad rods and trailing arm inserts that I have made up)

So no - don't know much about that....

My boyz machine is the X package, and his rear shock is in better condition than mine yet, and AFAIK neither have ever been replaced yet. (10 yrs old this yr)


My point was that if I git a bit of gas in my hydro - by his daffynition it is pnue.

But if I git a bit of water in my pnue, then it is hydro.

It seems that those two daffynitions don't come close, nor overlap each other, so it just seems like there must be something in between.

Maybe I need to ping ValCourt?


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Think Snow Eh!
Ox

OP - air cylinders are incredibly simple devices, but there are some very clever ways to get them to work in automation and fixturing. I'd suggest getting a bunch of catalogs and looking through application notes. The best training would be to hang out on someone's production line for a day or two. You'll get a lot farther that way than almost anything else. I can't remember the last time I needed to find PV/T, but the best solenoid valve to use on a mini suction gripper can be a handy thing to know.

And as has been pointed out, you probably don't want pneumatic control (air logic). This is (was) a very clever system of controlling mechanisms and such using air instead of electrical logic circuits. Timers, sequencing valves, the whole system was brilliant. Unless you need it for some unique reason, it's much harder and time-consuming to build with air logic than an out-of-the box PLC with solenoid valves. Plus with a PLC, you can combine solenoids, servos, and air cylinders as you need.

re air logic, can still be effective for simple applications, but the variables add up and can drive you crazy for anything that needs more than one or two steps. anti tie down logic blocks are a good example of something that works well.

I work with a nuts amount of pneumatic logic...It is often far more cost-effective than PLCs, and much, much easier to maintain or quickly modify. The other cool thing is that almost every factory in the world can give me something like 8 bar of crappy air...I can filter, regulate and have a usable air supply for a few $10 bills. I can't say the same about electricity. 220? 110? 50 Hz? 60? Is that sine wave clean?

The whole mess of logic valves, solenoids, flow controls, pneumatic timers, cylinders...There is some amazingly complex stuff that can be done.

Pour through Parker or Festo catalogs too, and look into something like fluiddraw:
Festo - FluidDraw S5 - Starter

Anyway, pneumatics are fun.

My first exposure to pneumatics was at the ripe old age of 18 in the context of propulsion control systems on tug boats, fishing boats and yachts . . . the big names back in the early 80s were Amot, Schrader Bellows, Wabco, Mathers, and we used a lot of Norgren valves for logic.

With an assortment of volume chambers, adjustable flow controls, 3-way, 4-way and 5-way valves and creative cylinder arrangements - you could manage smooth decel, shaft brake, shifting the twin disk, monitoring gear oil pressure, release of the shaft brake and smooth accel of a main engine regardless of what kind of monkey was at the command bridge.

They have mostly gone electronic now with PLCs and such - but one thing about a pneumatic system, it is bullet proof as long as you have a working air compressor, and if that failed - you often had a back up system powered from a CO2 bottle.

Just a thought somewhat interesting project would be to automate one of those 4x6 bandsaws for repetitive cutoff...then thinking hmmm...pneumatic counter is something I haven't seen before LOL.

Unfortunately, nothing beats the training of having to repair or modify a device which is already working and has drawings so you can study, try, etc.

I have had at least one pnuematic counter on a drill machine that I can think of.


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Think Snow Eh!
Ox

Some of our machines we have pneumatic counters on and others have pneumatic timers for the same reason. We use them to keep the purge air on the spindles for a set amount of time (or counts) after the machine is stopped. They work even if you power it off.

In the early 70's I went to a presentation by some IBM employees that detailed a complete system of pneumatic logic for running, I believe, a Card punch machine.

I was really annoyed that they appeared to have canned the whole program and did not market it outside of the company.

Chris P

New Scientist - Google Books