ferrite machining?
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From: Archimedes' Lever on 12 Jun 2010 11:05 On Sat, 12 Jun 2010 02:05:35 -0700 (PDT), Bill Sloman <bill.sloman(a)ieee.org> wrote: >to mean that soft ferrites didn't have a Curie >temperature. Bullshit.
From: Archimedes' Lever on 12 Jun 2010 11:07 On Sat, 12 Jun 2010 06:46:28 -0500, "amdx" <amdx(a)knology.net> wrote: > >"Yzordderrex" <powersupplyguy(a)netzero.net> wrote in message >news:a9090b31-6b08-4114-ae8a-37c5eed33788(a)u7g2000yqm.googlegroups.com... >> Does anyone know of ferrrite can be turned on a lathe? >> >> I have a short 1" long by 1" dia. rod ( i know, i know, a personal >> problem) and I would like to have a grove machined into it to accept a >> few turns of wire. there will then be a bobbin slipped over that with >> the secondary on it. >> >> I suppose this might be done with some type of grinder as well. >> >> Just curious to know what machining options are available for ferrite. >> >> regards, >> Bob >> > Maybe instead of all the grinding and since it is a rod with its incomplete >magnetic path. Can you install your bobbin, wind your secondary and >add the insulation amount of insulation needed and then put your primary >on the outside? Or wind your primary on the ferrite and use a larger bobbin, >( know limited sizes) > Do you have a high voltage problem you're working around? > Mike > I already posed this question.
From: Archimedes' Lever on 12 Jun 2010 11:09 On Sat, 12 Jun 2010 22:30:06 +1000, Grant <omg(a)grrr.id.au> wrote: >On Fri, 11 Jun 2010 20:20:54 -0700 (PDT), MooseFET <kensmith(a)rahul.net> wrote: > >>On Jun 12, 12:07 am, BlindBaby >><BlindMelonChit...(a)wellnevergetthatonethealbumcover.org> wrote: >>> On Fri, 11 Jun 2010 08:11:04 -0700, John Larkin >>> >>> >>> >>> <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >>> >On Fri, 11 Jun 2010 06:41:57 -0700 (PDT), MooseFET >>> ><kensm...(a)rahul.net> wrote: >>> >>> >>On Jun 11, 8:42 pm, Yzordderrex <powersupply...(a)netzero.net> wrote: >>> >>> Does anyone know of ferrrite can be turned on a lathe? >>> >>> >>> I have a short 1" long by 1" dia. rod ( i know, i know, a personal >>> >>> problem) and I would like to have a grove machined into it to accept a >>> >>> few turns of wire. there will then be a bobbin slipped over that with >>> >>> the secondary on it. >>> >>> >>> I suppose this might be done with some type of grinder as well. >>> >>> >>> Just curious to know what machining options are available for ferrite. >>> >>> >>Grinding is the way to go. If you want to cut something that >>> >>you would normally do with a lathe in metal, consider a tool >>> >>post mounted grinder. Watch the temperature rise. >>> >>> >Maybe a dremel with a diamond wheel? >>> >>> >John >>> >>> After the grooves get ground (any cutting attempt will result in >>> fracture), you need to cover the rod with transformer tape to insulate it >>> from your primary wire. >>> >>> If you make an open ended core transformer, it will be pretty leaky >>> unless you use a closed loop core arrangement. >>> >>> You would probably be better off with a pot core. >>> >>> I would use a dremel tool and grinding or cutting (abrasive cutting) >>> disc attached. >>> >>> If you are making a large groove for a single layer of larger wire the >>> grooves will allow the wire profile to sit a bit lower., >>> >>> If you are using fairly small primary wire, you do not need the grooves >>> at all. >>> >>> Temperature rise? They are not magnets. There are no properties to >>> lose via introduction of heat. >> >>The one partedness can be lost through the heat rise at the machined >>point. They don't conduct heat well and neither does the grinder. >>I stand by my suggestion that temperature rise be watched. > >I just spent some time with a high speed hobby drill, various grinding >attachments and a then piece of ferrite, a figure eight buckle type they >wind those mains filters on, the type with sprocket teeth on the coil >former so the ferrite is one piece. > >Anyway, 150 grit diamond tool rips into the stuff, black dust everywhere, >easy to fracture pieces off, very harsh if one applies too much pressure. > >The sanders and other grinders a bit more gentle, most gentle (but slow) >was the thin cutoff wheel when use with light pressure and kept moving >to avoid localised heating. If I tried too hard to grind one spot, the >ferrite would fracture from the hot spot, through several mm of ferrite. > >Machining ferrite is easy, with a little practice to develop a feel >for what is easy, and stuff that is dangerous in the sense of risking >fracturing the job. > >Diamond tools would need to be a lot finer than 150 grit to lessen the >impact and give a smoother finish -- easy to control with light pressure >and rips out the material quickly. > >Interesting stuff to play with. And try different tool speeds, the >abrasion rate doesn't necessarily go up with speed. Odd? > >Grant. Ever seen a pot core pair with mirror polished mating faces? They are abrasively finished.
From: BlindBaby on 12 Jun 2010 11:11 On Sat, 12 Jun 2010 09:35:16 -0500, John Fields <jfields(a)austininstruments.com> wrote: > >That is, since the subject of the thread is "ferrite machining?", one >with a modicum of sense would infer that the heat referred to was >generated purely by mechanical means and that the Curie temperature of >the material, at that point was immaterial. Jeez, I wish I could expound facts the way you do.
From: BlindBaby on 12 Jun 2010 11:12
On Sat, 12 Jun 2010 07:49:20 -0700 (PDT), mpm <mpmillard(a)aol.com> wrote: >With no dog in this fight, I have to agree with Sloman. >In technical writing, you cannot fault the reader for not >understanding what the writer intended. That's not what he did. He faulted him for the parts he failed to read. Like the TOPIC HEADER. |