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Big Country

Tube Cutting

17 posts in this topic

I have been informed that in the near future I have to build a new machine to cut, tap, and bend a tube. I have never built a machine that cuts a hollow tube before. But the tube is approxmitely 1/2 od and 1/4 id and need to shear it off or cut it in some way. I was wondering if anyone has dealt with this before or has any suggestions on what is the best way to go about this. I have looked at different types of rotating machines but I would like to some way shear it off with one cut, instead of messing with coolant. The problem that I fear with shearing the tube is it may dimple or egg shape the tube. Any suggestions will be greatly appreciated. Thanks in advance

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How will the raw stock be delivered to you? Sounds like a good job for an automatic screw machine. But you'd (probably) have to mess with coolant. If this is a big issue you might call some carbide tooling suppliers and see if you could cut it dry.

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It will be delivered in 10 - 20 ft peices. Probably more than likely 10 ft sections and the cut to length. Coolant is not really the issue because it will be in my stamping area which is nasty with coolant already fun stuff to work on by the way. What is a automatic screw machine?

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Are you sure you need to make one? Why not buy one?

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Here's a pretty good description: http://www.efunda.com/processes/machining/...rew_machine.cfm Cutting the tube to length would be a trivial operation for a screw machine. You could tap one one of it pretty easily, too. Tapping both ends is a little more difficult, but still doable. Typically this would be a second operation. The only problem with using automatics is they are becoming a dying art. You can buy a machine to run the job pretty cheap, but you'll have trouble finding a tradesman to set up and maintain the equipment. You company would probably be better off contracting a screw house to at least cut the tubes. You can do the tapping in-house if you want.. There's lots of companies that make (or made) drilling/tapping heads to do this.

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Check this out. We did about a half dozen different types of machines until the two guys that did all the controls left to make baseball bats. You can see that cutting does deform the tubes. It may be possible if you get a slower but sharper cutting tool. You can see that these guys wanted speed. http://www.deltamotion.com/applications/ca...ies/buckeye.php Buckeye had water jets that would clean the filings out of the tube. I don't think they ever threaded a tube though. We have worked with other companies that have.

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What volume are you looking for at a particular length? In otherwords will this be five of them at one length then 10 at another or are we talking about 1000s at a particular length

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I guess I should have expalined the process a little bit better. First we are planning on cutting the pipe to length and then automatically transfer it to another station where it will be drilled on both ends and then tapped. After that it will be sent to a bender to be bent. I have to lengths that I have to do one is about 16 inches the other is 4 inches. I guess now I still wonder if bending the pipe after it has been tapped will affect the tapped threads and wether I should bend it before I tap the parts. I will need to do rougly 4000 parts off from the machine per day.

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I guess it all depends on how deep the bend is and how close to the tapped ends the bend is. The best thing to do is to drill and tap one by hand, and then bend it in an arbor press. check it with a thread gage and see if is still within spec. Edited by gravitar

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How much deformation can there be in the tube at the bend?

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I am no tube bending expert but depending on how it is bent [method], there can be considerable deformation in the tube. Look at the difference in how the exhaust pipe in your exhaust system under your car looks compared to say a motorcycle frame or may be a roll cage in a race car. Edit..Here is a picture of how the tube can be deformed from bending. Edited by Bob O

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This is why there is hydroforming.

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Hey here's a thought.. go to this website and post what you are trying to do in the RFQ forum: http://www.cnczone.com/forums/index.php I don't know if management is dead-set on doing this in-house, but you may find that it can be done much cheaper outside

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Here is the machine that I found to cut the pipe that will keep me from getting much of a burr. http://inv.bassmachinery.com/q/webinv/0191...,40051,,,x,,,,c,

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Sounds like a plan! Are you planning on updating the controls or just leaving it as-is?

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Yeah I going to gut it, kinda looks dated.

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Well, at least it comes with a power cord

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