Author Topic: Precision cutting small diameter tubes  (Read 999 times)

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Offline qwaarjetTopic starter

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Precision cutting small diameter tubes
« on: April 23, 2023, 04:37:54 am »
Im looking for dust free way to cut 1/16 stainless tube without deformation of the tube. Conventional tube cutters tend to crush the tube or leave a highly tapered edge. Saws and grinders produce large amounts debris that travels up the tube, due to the small diameter conventional cleaning techniques are not very effective and i have high Foreign Object Debris concerns. Im looking for way to make square edge cut on the tube. I'm thinking chemical etching might work but would prefer mechanical solution. 
 

Offline PartialDischarge

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Re: Precision cutting small diameter tubes
« Reply #1 on: April 23, 2023, 04:50:49 am »
Everyone uses tube cutters or saws for the low cost.
For fancy applications there is water cutters, laser cutters and electrical discharge machining
 

Offline Dundarave

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Re: Precision cutting small diameter tubes
« Reply #2 on: April 23, 2023, 05:22:07 am »
Would inserting a solid, sacrificial material “backer” into the tube prior to cutting prevent the crushing?  And keep out any debris?  Either metal or some other suitable material.
 

Offline qwaarjetTopic starter

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Re: Precision cutting small diameter tubes
« Reply #3 on: April 23, 2023, 07:14:38 am »
yea i was thinking a purpose built edm machine might be the way to go long term
 

Offline jpanhalt

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Re: Precision cutting small diameter tubes
« Reply #4 on: April 23, 2023, 08:24:20 am »
Is the 1/16"tube thin wall or thick wall (assuming that is O.D.)?  For HPLC (thick wall) with compression couplings, you can file a notch and break.  Of course, the end is not square and polished.  I have also used a filler rod with grinding.  Cutting under water will reduce dust, but you will still need cleaning if particles in the tube are a problem.
 

Offline mikeselectricstuff

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Re: Precision cutting small diameter tubes
« Reply #5 on: April 23, 2023, 08:32:50 am »
Saw/grinder but/diamond wheel, while applying a positive pressure ( water or air) inside the tube, so any debris gets blown out?
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Online ejeffrey

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Re: Precision cutting small diameter tubes
« Reply #6 on: April 23, 2023, 11:53:02 pm »
I've always used a Dremel tool with a cutoff wheel.  Any other grinding tool will also give you a flat cut.  I've never had a problem with debris that I couldn't clean, but flowing air or liquid through the tube while cutting should make sure any debris gets swept away before it can travel up the tube in the wrong direction.
 

Offline coppercone2

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Re: Precision cutting small diameter tubes
« Reply #7 on: April 24, 2023, 12:09:36 am »
ehh if you try to cut titanium or something or even stainless with abrasives you can get alot of flashing, which is normally deburred, but if you want an actual geometric cut then you probobly need EDM

Oh, maybe a lathe would do it. But I still imagine they would debur a little. A thick tube on a lathe with minimum bur, but a thin one is very hard to cut

Cooling or under water might help alot

I never had spectacular results with 314 tube.

What you want to do is probobly just tolerate the grinding dust and instead pack a wadding on a string into the tube that you can pull out.
« Last Edit: April 24, 2023, 12:12:28 am by coppercone2 »
 

Offline johansen

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Re: Precision cutting small diameter tubes
« Reply #8 on: April 24, 2023, 12:14:24 am »
File a notch then bend it back and forth till it breaks .

What a friend of mine has me do for some stuff is to drill out a 1/8 copper tube, insert the stainless, braze the tube at both ends, then file the end flush all the way back to the braze. This lets you use brass compression fittings to compress and seal on the copper, while minimizing to near zero, the  exposure to copper and braze.

Acetylene torch tip cleaners are a good way to clean up the internal bore.
« Last Edit: April 24, 2023, 12:17:02 am by johansen »
 

Offline coppercone2

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Re: Precision cutting small diameter tubes
« Reply #9 on: April 24, 2023, 01:06:12 am »
the manual specifically said not to because you will curse your existence when you can't clean the acetylene nozzle (get a spare one)

I never recommend using the torch tools for anything but the torch because when you use the torch you are in torch man mode and the last thing you want to worry about is the integrity of a nozzle reamer when something is smoking hot lol. avoid a heart attack every time that torch tool kit works . IMO broke tools when something is glowing = biggest "i can't believe this fucking shit are you fuckin kidding me' ever.
« Last Edit: April 24, 2023, 01:09:11 am by coppercone2 »
 

Offline beanflying

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Re: Precision cutting small diameter tubes
« Reply #10 on: April 24, 2023, 03:46:43 am »
With the correct geometry/speed etc then parting off in a lathe will work fine. Regardless of process you will still need to just touch the inside of the bore to break the edge burr.

Plenty of good stuff from Stefan on various micro machining jobs. While this is a larger than yours it is fairly close. Watch the whole video as there is plenty to be learned.

https://youtu.be/QJIdKqzWuDY?t=2825
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Offline Doctorandus_P

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Re: Precision cutting small diameter tubes
« Reply #11 on: May 06, 2023, 12:16:59 pm »
The normal (high volume production) is to score them over a sharp edge untill they break. This is quite similar to using a pipe cutter with a round knife wheel.
See the video below @01:20.



And afterwards, grinding and cleaning. EDM also creates a lot of debris, so even with EDM you will have to clean the tubes afterwards.
 


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