Apprenticeship dielectric question

I have another head scratcher apprenticeship question.
I am being asked to explain the application of dielectric fluids with regard to a range of different materials.
I understand the general purpose of the dielectric (for the spark to happen, to flush eroded material away and to cool), but I have no experience or knowledge of the various dielectrics with different materials. I only use DI water with carbide.
I'm not having much luck searching the internet either. The only thing I have found is that ferrous materials corrode during machining in DI water. I don't think this qualifies as "a range of different materials".
Please help, (again)

We know nothing of your specific question.

But in cases such as this, searches here , but another source is to the vendors who sell the product used in whatever your question is.

They should have a catalog of products with data sheets explaining their function.

That should give you a list of available products combined with their applications.

Others may be able to provide specifics based on their exeriences.

Sent from my SAMSUNG-SM-G930A using Tapatalk

"I am being asked to explain the application of dielectric fluids with regard to a range of different materials."

Chris, I've been engaged in EDM longer than I care to admit and I'm not sure I could explain this without a better-constructed sentence or additional information.

Do they want to know the differences between DI water and oil?
(Ex: Titanium cuts 20% faster than steel in water, but cuts slowly and with high-wear in oil)

Try to get more information so we can better help.

Bud Guitrau

I get the impression that they want me to explain why I might wish to cut a certain material in oil vs DI water, though I'm not sure why they think that someone starting out would know this. If they hadn't put in "with regard to a range of different materials" I could answer it in a flash.
One thing I have to try to bear in mind is that these are supposed to be single paragraph or thereabouts answers, so they're after a simple answer. This makes me think that it's just a badly worded question and all they're after is what the dielectric is for.
If the experts don't know, then I think I'll assume that all they want is that ferrous materials corrode in water but not in oil.
Thanks for the input

Hi ChrisC_84:
The discussion around oil dielectric in wire EDM cutting of carbide is predominantly one that speaks to the leaching of the cobalt binder from carbide with water dielectric.
This leaves unsupported grains of tungsten carbide at the edges of any part wirecut with water, and is a major contributor to premature edge breakdown of wired carbide cutting tools.

The leaching process is multifactorial, and I don't know the details of the chemistry involved, but the upshot is that with oil dielectric the cobalt leaching is trivial whereas it is severe with water dielectric.
So all carbide cutting tools benefit greatly from being wire cut in specialized oil dielectric machines specifically built for the purpose.
In fact, they are considered to be almost as good as ground cutters for longevity whereas a carbide cutter wire cut on a conventional machine is maybe half as good as a ground cutter.

Coming from the background that you do, I'm surprised this hasn't been beaten into you from the first day...it's pretty common knowledge among makers of carbide tooling.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

The cutting tools we make are all ground. I've never been asked to wire them.
I have no idea about all the other things that I do wire cut. I'd imagine it depends on what the carbide binder is.

Just about nothing has been 'beaten into me'. I haven't been taught about carbide.
The other unit I picked as part of my apprenticeship was turning and I've had no tuition at all.
I wish I had someone to learn EDM stuff from directly but I'm the only one that runs the wire machines. I always thought it was odd that they seemed comfortable with an apprentice being the only wire operator. I thought that apprentices had a kind of mentor that they learned from. No such luck where I work.

Wire EDM in oil is for a better product when dealing with Carbide. Wire EDM in water is faster as some people have mentioned. I don't think I have ever heard of a sinker EDM using water. Almost 100% sure its always oil. It used to be kerosene from what I understand. Also mention many oil EDMs have burnt down many a shop on overnight burns.

Hi,

Absolutly Sinker machines use oil based on kerosene and it's true that can be dangerous to leave the machine by the night working unless you have a GLORIA or fire extinguisher system. That must be placed before machine runs by law.. almost in Europe.

Regarding the question of how the DI water affects to any material, in the technologies of the machine there's a parameter (in Mitsubishi in this case) LR that means liquid resistivity and usually always has the same value. The DI water should be between 11 and 15 microSiemens in order to achieve all the benefits for the erosion as you know cooling, isolating the gap, etc.

Best Regards.