bending pipe 1

[preeve79]

Dont know if this is the best place to post this question. But need some help.
I need to make a coil out of pipe. 1-1/4" NPS SCH 80 pipe. I need to roll it 10 times on a 20" diameter.
Our company currently uses an electrical motor with a bunch of gears. The teeth of the gears are always breaking. So we want to try out hydraulics.
Does anyone have any recommendations? Sizing or power? I am very inexperienced in this area and need help....

any advice would be greatly appreciated.
thanks
pete

 

[MikeHalloran]

I infer from your grotesque of a question that your company is currently successfully coiling pipe with an electromechanical bender, that said bender breaks some of its gear teeth occasionally, and that you, poor innocent, have been tasked with fixing the problem.

No, check that. You have been tasked with implementing some other person's conjectural solution to the problem, by 'trying out' a different means of powering the bender.

You have been finagled into a no-win position. If you solve the problem, the other person gets the credit. If you fail to solve the problem, you get the blame. That part of the problem is not technical. Be very wary of that other person in the future; all interaction with him/her is a career decision.

There is no magic in hydraulics; it's just a way to achieve power transmission through tight spaces. As an engineer, you will eventually learn that the information you need in order to design and size a hydraulic system for this application is pretty much the same information you need to figure out why the gears are breaking.

One way is to reverse- engineer the machine, figure out how it's supposed to work, and find out why it has a weak spot, or how it's being abused.





Mike Halloran
Pembroke Pines, FL, USA

 

[CorBlimeyLimey]

There may be no need to "jump ship" to another process. As Mike suggested, investigate the current machine to find why the gears are breaking & if a fix can be implemented. eg. A shear pin (or other drive component) should be sized to break before a gear tooth fails.

What type of gears are being used? Some are better at transmitting higher loads than others.

What material are they made of?

Can the pipe be annealed?


Helpful SW websites FAQ559-520
How to get answers to your SW questions FAQ559-1091

 

[JStephen]

The hydraulic solution need not be a "rolling" operation- you could make up a couple of dies and press short lengths of pipe to form it.

Is this a commercial pipe/angle roll that's breaking down? Or some sort of home-made machine?

Another option is hot-forming.

And consider the simplest solution: hiring someone with the right equipment to do it.

 

[insult2injury]

Seems to me if it's commercially produced, you are either exceeding the rating of the bender or it's a bad product. Either way, there are many hydrualic-driven products already on the market, and it sounds like you need a new one.

 

[okeng]

Mike's analysis of your political problem sounds eerily familiar.

Find the best local hydraulics distributor (probably the Parker reps), and try to hand the whole thing off to them. They'll come up with a nice, reliable, very expensive solution that will work, and be very happy to sell you all the components you need.

Just make sure you extract all the information and education you can out of them in the process, and make sure they are set up to take any stray blame that might splash out.

Wait--that part sounded kind of cynical.....

Actually, there are people that make machines to roll coils, and I don't think they are very expensive (as machine tools go). If you are dealing with an ancient, homebrewed machine, you might be able to source a brand new machine that will make better parts faster for far less money than it will take to convert it to hydraulic drive. If you do this, make sure the plant maintenance guy knows what a huge favor you did him.

Have fun,

Jess