Thin slots in tube

[bretthydra]

I require to produce 8:ff slits, 0.2mm wide X 165mm long in the wall of a tube which is 56mm o/d X 50.8 i/d. I have enquired about laser and water jet cutting and been informed that these are not suitable for this application. Wire erosion is a possibility. Any ideas?

 

[unclesyd]

A little more information is needed.

How many pieces of what material?

What is the quality or precision requirements of the slot?

 

[MikeHalloran]

Laser and waterjet cutting will work, if you cut the slits in a rectangular blank and then roll the blank into a tube.

There are some laser-based tube notchers that could work on the tube in its round state, but I get the impression they're sold into tube fab shops that don't do small jobs

EDM is possible if the tube is electrically conductive, a fact not in evidence so far.

Wire EDM would require that the wire pass through both walls, or out the end, both of which require special tooling.

Or you could find a cranky old machinist, who would probably use a circular slitting saw blade in a horizontal mill.



Mike Halloran
Pembroke Pines, FL, USA

 

[bretthydra]

Yeah,
sorry for the lack of information.
The tube is machined from carbon steel bar (EN19).
The finish of the slits is not critical.

 

[unclesyd]

All of the above plus Sinker EDM.

The possibility of Electrochemical Milling.

They are people who do Micro Laser Machining that can do the job.

http://www.incisiontech.com/services/electrochemical_edge.html

http://www.extrudehone.com/ecm.html

 

[MikeHalloran]

If the tolerances really are not critical, I've seen marine exhaust fabricators cut slits like that with a plasma torch, by hand. Nothing will be faster.





Mike Halloran
Pembroke Pines, FL, USA

 

[CorBlimeyLimey]

Mike ... A plasma torch, by hand, cutting an .008" slot ?

 

[MikeHalloran]

Maybe a little fat of 8 mils, but straighter than you'd expect. Depends on the artisan, of course.



Mike Halloran
Pembroke Pines, FL, USA

 

[Cockroach]

In the oil industry, downhole completions uses identical devices for sand control, i.e. slotted liners. In this case, a laser is used to cut a very thin slot into the OD of casing, then rolled to cold work the width into yet a narrower final form. In this fashion, widths of the slots are extremely narrow, allowing fluids to flow into the casing annulus through the narrow slits, yet prevent sand from being carried with the flow.

Patented technology, several of which can be found on line. But essentially what you are trying to do is about twenty years old.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

 

[Compositepro]

I don't see how the tolerances could not be critical on slots that are 0.2mm (0.008")wide by 165 mm (6"). If you cut such slots in a tube, the internal material stresses will change the slot width as you cut.

 

[berkshire]

Are you making the tube by boring a solid bar? If you are you may be ok.
If you try to do this from tubing, the slot will widen as it is cut, unless you stress relieve the tube first.
A sinker EDM using shim stock for an electrode may be your best bet.
B.E.