Anyone have experience EDMing neodymium magnets

SBAER · Apr 13, 2013

I design and build prototype electric motors with arc segment shaped rare earth magnets in them. The magnets are manufactured in China and I can order them to size but it takes about 5 or 6 weeks to get them. Has anyone here shaped a magnet with either a wire or sink type edm? With the wire, the two parts formed would repel each other and this might cause them to fracture? Anyone interested in trying (I would pay and supply the magnet of course).

dsergison · Apr 13, 2013

I could try to do that for you. I have no experience with it but my Robofil 290 is rarely in use, and I have really quick turn around. I like weird stuff. email me.

Zahnrad Kopf · Apr 13, 2013

I have done a lot of that, actually... Exactly as you describe, save that the magnets were U.S. manufacture. The key is in the fixture. This keeps the "drop" from flipping over. Every now and again, you get one that wants to flip opposite, essentially pinching the wire. I'll see if I've got any pics of the set-ups.

SBAER · Apr 13, 2013

On Monday I'll prepare some drawings. Does the dross (or whatever you call it) remain magnetic or does it lose its magnetic properties?

Zahnrad Kopf · Apr 13, 2013

I just realized that you were asking to have someone do this for you. ( I was rushed and did not read all the way through ) I'll be happy to look at your drawings, but did not intend to step on Dan's toes. If he is still interested, please send them to him as well so he can quote it as well. Yes, the cut debris still remains magnetic, but it is so minute of particle that it is of little consequence, other than accumulating on other magnetic things, given the chance. I actually keep a bag of VERY strong neo mags at the return, on the table, so that ALL debris gets caught there, before heading into the filter tank. I clean the "mag bag" once a week.

Zahnrad Kopf · Apr 13, 2013

Side question - Are you doing the lams, too? Or are you using something already existing and making the mags to fit the lams? This is interesting to me as I've made the lams, the mags, the fields ( housing and gluing the mags ) and the armature shafts with gears. It's pretty cool, putting all the components together and watching them "go 'round" afterwards.

smalltime · Apr 13, 2013

I am NOT an EDMer, but I do have a question:

Aren't you all concerned with the swarf from your cutting sticking to everything INSIDE your machines?

We don't do this stuff, just for that reason.

Zahnrad Kopf · Apr 13, 2013

smalltime said:
I am NOT an EDMer, but I do have a question:
Aren't you all concerned with the swarf from your cutting sticking to everything INSIDE your machines?
We don't do this stuff, just for that reason.

Nope. Wire machines are almost completely Stainless, where any of this matters. And, like I described, above - I have extra measures in place, as well.

SBAER · Apr 13, 2013

I get the lams laser cut, from a place in Alabama that specializes in this, the results are pretty good, I'd say within 0.002". I am building brushless DC motors with the magnets on the outside. What kind of motors are you working on?

Winker · Apr 13, 2013

Does the heat affect magnetic properties in any meaningful way?

dsergison · Apr 13, 2013

by all means, use Zahnrad. I've never cut a magnet so I did read a little about it and it seemed like a neat thing to try. I am rather interested and would not mind trying, even just for fun.

SBAER · Apr 13, 2013

Winker said:
Does the heat affect magnetic properties in any meaningful way?

I am curious about this as well, what I am hoping is that only a thin layer is affected. I will have to do some tests to prove this too myself

Zahnrad Kopf · Apr 13, 2013

SBAER said:
I get the lams laser cut, from a place in Alabama that specializes in this, the results are pretty good, I'd say within 0.002". I am building brushless DC motors with the magnets on the outside. What kind of motors are you working on?

I'm making parts for AC and DC brushless motors. Beyond that and what I've already disclosed, I can't say much more... :cool:

Zahnrad Kopf · Apr 13, 2013

Winker said:
Does the heat affect magnetic properties in any meaningful way?

The heat of the cut, or heat in general? From the cut, not so much... from heat in general, yes, quite a bit. But Neos come in varying levels of quality that respond to heat in varying degrees of loss. Some lose mag at 250°F and some are good up to 450°F.

Zahnrad Kopf · Apr 13, 2013

dsergison said:
by all means, use Zahnrad. I've never cut a magnet so I did read a little about it and it seemed like a neat thing to try. I am rather interested and would not mind trying, even just for fun.

Dan, shoot me an E and I'll send you one to play with. They're paradoxical - they're fun little buggers with tons of uses, but can offer SO many headaches, as well...

EDM AE · Apr 15, 2013

In typical production processes involving Neodymium Iron Boron, the magnets are wire EDM'ed BEFORE they are magnetized (yes, the material starts out as non-magnetic). This material is quite easy to manage and machine in the wire EDM in its non-magnetic state. There are various sources around which can supply material in this state as well as perform the required magnetization after wire EDM (or other) machining.

Zahnrad Kopf · Apr 15, 2013

Agreed on all counts, but not very applicable to rapidly prototyping. Most times, it's just easier and quicker to buy mags that will work and cut them to size and/or shape.

azindustries · Apr 11, 2023

SBAER said:
I design and build prototype electric motors with arc segment shaped rare earth magnets in them. The magnets are manufactured in China and I can order them to size but it takes about 5 or 6 weeks to get them. Has anyone here shaped a magnet with either a wire or sink type edm? With the wire, the two parts formed would repel each other and this might cause them to fracture? Anyone interested in trying (I would pay and supply the magnet of course).

Always best to EDM the magnet material in the unmagnetized state and then remagnetize them afterwards. Neodymium can be heated above their max working temperature to demagnetize them. We can help with either the demagnetization or the magnetization of the magnets. Unfortunately, we don't have a wire EDM.

SBAER said:
I design and build prototype electric motors with arc segment shaped rare earth magnets in them. The magnets are manufactured in China and I can order them to size but it takes about 5 or 6 weeks to get them. Has anyone here shaped a magnet with either a wire or sink type edm? With the wire, the two parts formed would repel each other and this might cause them to fracture? Anyone interested in trying (I would pay and supply the magnet of course).

Waakzaamheid · Apr 11, 2023

A very timely response.

Anyone have experience EDMing neodymium magnets

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