cutting the tape wound core with wire edm

[herbertkabi]

Is it possible to cut axial slots to the tape wound core. 0.5mm soft magnetic iron (Fe,Ni,Si) tape, enameled and wound as ring with (or without) adhesive ( like toroid power transformer core). Both oposite flat surfaces of the core are grinded - lacquer-free , clean surfaces. OD 10", ID 8" and h - 2" , 18 slots.
I was in local EDM shop and the chief told me that it is not possible to gut with Wire EDM because the lacquer and adhesive between the winds of the iron tape. Not more explanations from this guy, the only one was - "it is not possible". May be he just does not like stupid iventors ;-)
My opinion is that "-" electrical connection comes via grinded flat surfaces of the core and all surface could be used for connection.
I dont believe that the thin film of lacquer between the winds of metal tape will break in on the process or mechanically does impede the wire.
What is your opinion?
Thanks,
Herbert

 

[Goahead]

Can you test that you have electric flow in the internal laminations if contact is only on the external surfaces?
Unless you make an electrical connection to each one of the internal laminations (on a side that will not interfere with ED cutting) how can those be a part of the electric circuit? If they are insulated there will be no spark and no cut.

http://www.welding-advisers.com/

 

[Hydroformer]

ANYTHING non-conductive in the path of the wire will stop the process (including air sometimes). Weld inclusions / voids are probably the best example I can think of right now.

In any EDM process the electrode (or wire) never makes contact with the subject material. If it does, machines will typically reverse the tool path in an effort to correct a short-circuit.

Although we call it "wire-cut" the wire is only a vehicle for the electrical energy. The material is 'burnt' from the subject and flushed away by the dielectric fluid.

regards,

Hydroformer

 

[herbertkabi]

Even thin film of lacquer will destroy yhe process, even it does contact edgewise the moving wire ?
It is iron alloy tape wound core. I need to cut axial slots to the both sides, to the both flat surfaces. These surfaces are grinded. When to start to cut the wire will take edgewise all layers of this core at the same time. No way?
Regards,
Herbert

 

[Hydroformer]

I've spent hours fighting my way through a weld inclusion (silicate) to notice after cutting that the inclusion was so tiny it was barely visible.
By 'fighting' I mean continuously re-threading broken wire only to have it break on contact. The best you can do is take the wire speed to the max, 'on time' and current to min. and hope to erode enough material around the inclusion to allow the solids to be flushed away.
Your lacquer would represent hundreds of these inclusions.

As great as EDM technology is, it's very intolerant to foreign material in the path.

regards,

Hydroformer

 

[Timelord]

herbertkabi,

Find someone with a waterjet cutter and see if they can do what you need. A waterjet cutter doesn't care what the material is, it cuts by friction erosion rather than spark erosion so it doesn't care if the material is a conductor.

Timelord

 

[Hydroformer]

True enough Timelord...
Laser-cutting may be an option too.
Herb, how thick is the section to be cut ?

regards,

Hydroformer

 

[MikeHalloran]

EDM will only cut conductive materials.

You might take your assembly to a monument maker and see if he can cut it with a diamond wire saw.



Mike Halloran
NOT speaking for
DeAngelo Marine Exhaust Inc.
Ft. Lauderdale, FL, USA