Air cylinders circuit line 1

[steinbaden]

Hi Team
(Please see the attachement)

* I used Four 80mm Cylinders to lift a single Steel plate, My Air pressure is 6bar and circuit dia is 8mm.

--My question is

Do i need to make my Air circuit fully balanced. or is it okay if i draw a simple circuit as shown in the attachment

can someone please really explain me the concept (Because in feature i planned to operate with 8 actuators, then balancing becomes more complicated)

Sakthi

 

[Jboggs]

I have a feeling you haven't told us all your requirements. If the attached circuit diagram is all we have to go by I can tell you that functionally there is no difference between the two options. However, there is SO MUCH more we need to know to give you any kind of good answer. For example, what are the functional requirements? How fast do these cylinders have to travel? What is their stroke? What is their duty cycle? How are they connected mechanically? You mention "balancing", but exactly what do you mean by that? Is it critical that they all extend and retract together? (Not going to happen.) What force must they exert? Is their load equal? A drawing would help A LOT!

 

[steinbaden]

Hi

See my attached image

Now i tried to explain bit more in details

Regards
Sakthi

 

[Occupant]

I wouldn't do it that way. E.g. if you would use air/oil and let's say develop 500psi then a single 3"dia. cylinder would do the job and you wouldn't have to face the balancing problem with multiple air cylinders.

 

[MikeHalloran]

Air doesn't work like you think it does.

You want all the tapered pins to move together. That's what die sets do. You can buy them for much less than it would cost you to make them.

Moving and guiding the die set is what punch presses do. Again, cheaper to buy.

Punch presses can be powered by slider cranks as usual, or by any number of air cylinders.
Again, cheaper to buy than make.


Mike Halloran
Pembroke Pines, FL, USA

 

[steinbaden]

Hi Mike

Thanks for the quick answer

but my application is little different, so i would like to use the way in the image

 

[steinbaden]

Hi Occupant

Thanks for the comments.

So it means we do not have to really balance the Air cylinders,,isnt it !!?

 

[Occupant]

I don't know, how you can come to that conclusion unless you are saying, since there aren't any air cylinders anymore, we don't have to balance them - which would be true. See the attachment for more of an explanation.

 

[Occupant]

Sorry, made a mistake. The picture shows a unit with a fast approach setup which wouldn't work in your case since the fast approach is still by air. You would have to use one that is strictly air over oil.

 

[MikeHalloran]

Multiple hydraulic cylinders don't naturally balance any more than multiple air cylinders do; i.e., they don't.

If you want multiple cylinders or multiple objects powered by cylinders to move in unison, you must synchronize them mechanically (or with multiple linear position sensors and fancy controls).

Linear slides (as built into punch presses) are one way to do so.
You can also use crossed double torsion arms, or do some fancy stuff with roller chains and lots of sprockets, shafts, bearings, pillow blocks, and structure to support all that stuff.

The variations in plumbing that you have documented will not behave differently from each other, and neither will solve the problems you will encounter.

The binding you will encounter is fully explained in the typical sophomore kinematics problem involving a clown or other toy with eccentric mass that does not smoothly slide on a stick. With metal surfaces and tight clearances, the problem is even more extreme. In fact, several linear shaft brake mechanisms rely on the principle involved, and they work very well.


Granted, you have no basis for trusting my word.
Go ahead and build a prototype of whatever you think will work.
Build it and test it as quickly, cheaply, and quietly as possible, so as not to draw attention to the expense of your learning process.


Mike Halloran
Pembroke Pines, FL, USA

 

[Jboggs]

steinbaden - The posters know what they are talking about. Groups of pneumatic or hydraulic cylinders when supplied by a common source will not move equally. The smallest differences in internal or external friction, or flow restrictions, or any number of other things can create huge differences in relative movement. I am curious, exactly what do you mean by "balancing"? I know what I think you mean, but what do you see in your mind when you picture balancing? For example, are you considering adding or subtracting some weight at one or more lift points in an effort to "balance" the load? I think all apprentice mechanical technicians have tried that at one time or another. It never works.

 

[steinbaden]

Hi Jboggs

Thanks for your reply.

The Term i used ''BALANCING'' is just only because,if you see my picture (attached)

all i wanted to move the 36mm Steel plate parallely towards forward and backward.

i only had doubt if i should feed my Actuator with same equal length of Air Circuits


Regards
Stein

 

[Jboggs]

The length of the air circuit will have very little to do with the coordinated motion of the cylinders. If you want the motion to be coordinated you must have some mechanical method of guaranteeing that (rack and pinion, linkages, linear bearings, etc). Then you can drive that mechanism with one or more air cylinders. But the air cylinders themselves will not guarantee coordinated motion.

 

[Jboggs]

steinbaden - check here:

http://us.misumi-ec.com/us/ideanote/detail/000208.html