machining magnets

[pyroracing85]

Is it possible to cut a magnet without cracking it or anything? I wnat to design something with these magnet.


please help
-garrett

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[Swede]

I've tried machining neodymium. The chips were a bit pyrophoric, i.e. some of them burned. Be careful! Don't know how unhealthy the fumes from a burning, rare-earth magnet can be. At least with neodymium, it was hopeless. Cracking was almost inevitable. The best results were had by embedding the magnet into a pocket of aluminum with epoxy. The epoxy supported the edges of the magnet. Once done, the epoxy can be chipped and peeled free. Perhaps there's a better way to embed one, but I gave up the effort due to the scrap rate.

RE Magnets are usually sintered from powder, rendering them glass-like in structure. The chips, of course, stick everywhere and are a real nuisance. I wish you luck!

[HuFlungDung]

I drilled a hole in a neodymium magnet the other day. I used a resharpened masonary drill. I still experienced a bit of breakout on the under side. Your best bet is to purchase a properly molded magnet.

[ToyMaker]

Sounds like the perfect application for an EDM setup.

robotic regards,

Tom
= = = = =
“I was a failure in Boston . . . because they thought I was too fashionable to be intelligent, and a failure in New York because they were afraid I was too intelligent to be fashionable.”
-- Edith Wharton

[pyroracing85]

I had ideas of making a magnetic bearing. It wouldn't have to support to much weight but I just wanted to see if it would work. but unless i can figure a way to cut the magnet. this isn't going to happen

[Konrad]

One place I worked ones in Switzerland, they put allot of holes into magnets by EDM.

[pyroracing85]

so drilling no, edm yes? sounds good to me. I know of a guy that has an edm.

[DAB_Design]

I found this info...thought you might want to take it into consideration .....

via www.wondermagnets.com

Drilling and Machining: Neodymium magnets are by nature very hard and brittle. Although they can be cut, drilled and machined, it should ONLY be done by folks who are experienced with ceramics. If the magnets get over about 260 deg F, they will lose their magnetism permanently. They are flammable, and it is not difficult while grinding or machining to get them (or the chips and dusts from cutting) so hot that they ignite. If they do ignite, the fumes are toxic and the material burns very fast and hot, like Magnesium! In our experience any machining of these magnets should be done with diamond tools under lots of coolant with good ventilation and the risk of fire in mind.

[Swede]

I found this info...thought you might want to take it into consideration .....

via www.wondermagnets.com

Drilling and Machining: Neodymium magnets are by nature very hard and brittle. Although they can be cut, drilled and machined, it should ONLY be done by folks who are experienced with ceramics. If the magnets get over about 260 deg F, they will lose their magnetism permanently. They are flammable, and it is not difficult while grinding or machining to get them (or the chips and dusts from cutting) so hot that they ignite. If they do ignite, the fumes are toxic and the material burns very fast and hot, like Magnesium! In our experience any machining of these magnets should be done with diamond tools under lots of coolant with good ventilation and the risk of fire in mind.

Wonderful! Now I know that burning pile of Neodymiun flakes was toxic. I've probably destroyed my liver and kidneys machining a stupid magnet!

[ESjaavik]

@Swede:
Well I see you are still here, so maybe it was not too bad.

I've not heard that it is very toxic, also see here:
http://www.scescape.net/~woods/elements/neodymium.html
And are you sure it was Neodymium? Was it covered in a layer of Nickel (looks like it is plated)?

One point with Neodymium is it should be protected from the atmosphere or it will
quickly deteriorate. The reference above does not go in depth on that, but it means
there is no way an amateur can machine it and then re-protect it without exposing it.

But you may well think it over what you are machining. Some fairly common materials can be extremely toxic under special circumstances. Like PTFE (Teflon[TM]) or beryllium. The last is most commonly found in beryllium-copper.

[Epik]

While it does not deal with magnetism I would like to ask if you have any occurances you know of in which aluminum machining has caused any of your firends/workers/coworkers to develop alzheimers. My instructor has a friend who worked at rockwell for 25 years mahcining aluminum and had HUGE amounts of aluminum in his blood. I understand that aluminum is now believed to be a cause of alzeheimers. I myself have a grandmother dying of alzheimers. She went from being a college magna cum laude for OSU to not being able to velcro a shoe. I don't want this to happen to me especially since I am genetically prone to it. Are there any safety equipment out there to prevent this?

[2muchstuff]

I'll have to agree with ESjaavik on the beryllium-copper, that stuff is nasty. I build radio controlled scale boats and when it comes to the finishing of the propellors, I now use the ones made of brass. My nose and sinuses would fill up within minutes and drain into my chest making it hard to breath, all because of the grindings and filings. To top it off, the symptoms would hang on for about a week.

[masterblaster]

I have cut many magnets. I almost always grind them . I have even ground them in a lath with tool post grinders or used mounted stones on 1/4 shanks in a verticle mill or drill . Keep them cool with a spray of coolant.

[jkeyser14]

Anyone try to cut them using a waterjet? It would keep the temperature down so they wouldn't lose magnetism, and it takes off so very little at a time that I doubt they would have cracking problems.

[alnicov]

What type and thickness of magnetic material are you trying to cut? My supplier uses a water-cooled diamond impregnated rubber disc for alnico formulations. Occasionally I dry cut .187 dia. slugs with a fiberglass reinforced cutoff wheel. Unfortunately they tend to lose some magnetic strength and need to be re-magnetized.

[zinnoon]

Is it possible to drill Neodymium magnet using tungsten carbide drill bit. The drill bit is 0.028 (#70)

Zinnoon

[zinnoon]

Is it possible to drill Neodymium magnet 1/4 inch width using tungsten carbide drill bit. The drill bit size is 0.028" (#70) or using diamond drill bit size 0.0590" (1.5 mm)

Zinnoon

[underthetire]

Grinding or edm only on magnets. Some magnets are very hazardous actually, depends on the composition. Be copper is really not that bad, since the be is bonded in the copper, it doesnt become airborne. You can actually contact brush wellman if you want true answeres. They have a be program similar to the one i have at work, and seem to be willing to share. I really wish our on line training was available to the public, there are some very good programs that could help a lot of people.

Btw, magnetic bearings have been around for quite a while. I remember seeing a 100k rpm spjndle at mori japan that was magnetic, although i think it was a electro magnet hybrid.