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Re: FABRICATING MAGNETS


From: 	Geoff Schecht[SMTP:geoffs-at-onr-dot-com]
Sent: 	Wednesday, November 05, 1997 12:38 PM
To: 	tesla-at-poodle.pupman-dot-com
Subject: 	Re: FABRICATING MAGNETS





>>
>>In connection with Tesla work I'm interested in making custom-shaped, and
>>sized magnets.
>>
>>If it is possible, and practical within reason, I would like to buy
>>rare-earth in powder form, and, in some manner, bond, mold, compress,
>>shape, machine, or otherwise fabricate magnets to exact custom shapes,
>>strengths, and sizes.
>>
>>EXACT magnet geometry is very critical for many experimental projects, and
>>the cost of factory-made custom magnets can be prohibitive, especially on
>>an experimental project where many sizes and shapes may have to be tried
>>and rejected before finding the ones that work.
>>
>>I have already located some plans for building magnetizers, but would also
>>appreciate more input on that, as well as how to achieve maximum
>>magnetization without destroying the magnet. I believe that rare-earth
>>magnets require a more powerful magnetizer than many of the less-powerful
>>magnet types.
>>
>>I would appreciate any detailed info I can get on this, as well as parts
>>and material source references.
>>
>>Thanks,
>>
>>Alan G. Pope
>>
>Alan:
>
>I hate to be the bearer of bad news but, in essence, forget it. Unless you
>plan on going into competition with the likes of TDK or Magnetics, Inc
>you'll wind up spending $$millions on a plant with the proper pressing,
>sintering and controlled-atmosphere annealing equipment to process magnets
>or just about any powdered metal/ferrite. This is big, industrial stuff;
not
>something that you can do at home with a hydraulic press and a hot plate
>:-). True, some universities have the equipment to make superconductors,
>magnets, etc in their labs but they're as well equipped as a pilot
>production plant in most cases.
>
>While it's conceivable that you could machine magnets at home, you'd have
to
>invest in diamond tooling to do so successfully. If you really need to have
>a custom magnet fabricated, places like PerMag can do it for you but expect
>to pay several thousand dollars in NRE's and tooling costs.
>
>Impulse magnetizers are probably the easiest things to build as far as
>magnet processing gear is concerned. It's very difficult to get them to
>charge a magnet to a particular field strength; in order to get a magnet to
>take a charge I believe that you have to hit it way past its saturation
>point and then when it relaxes, what you've got is what will be there for
>the life of the device. You can control the remnance magnetism to a point
by
>how you anneal the structure but then you're getting back into the
>controlled-atmsophere furnace problem again.
>
>Geoff
>
>
>