ferrite machining?
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From: Bill Sloman on 12 Jun 2010 12:02 On Jun 12, 5:11 pm, BlindBaby <BlindMelonChit...(a)wellnevergetthatonethealbumcover.org> wrote: > On Sat, 12 Jun 2010 09:35:16 -0500, John Fields > > <jfie...(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. Sadly, he does. -- Bill Sloman, Nijmegen
From: Bill Sloman on 12 Jun 2010 12:03 On Jun 12, 5:47 pm, John Fields <jfie...(a)austininstruments.com> wrote: > On Sat, 12 Jun 2010 08:11:03 -0700, BlindBaby > > <BlindMelonChit...(a)wellnevergetthatonethealbumcover.org> wrote: > >On Sat, 12 Jun 2010 09:35:16 -0500, John Fields > ><jfie...(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. > > --- > Thank you, that's very kind. :-) But, granting that the admiration comes fron BlindBaby, not worth much. -- Bill Sloman, Nijmegen
From: Bill Sloman on 12 Jun 2010 12:18 On Jun 12, 2:47 am, BlindBaby <BlindMelonChit...(a)wellnevergetthatonethealbumcover.org> wrote: > On Fri, 11 Jun 2010 19:25:07 -0500, Jim Yanik <jya...(a)abuse.gov> wrote: > >Sjouke Burry <burrynulnulf...(a)ppllaanneett.nnll> wrote in > >news:4c12c34e$0$14129$703f8584(a)textnews.kpn.nl: > > >> Yzordderrex 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.. > > >DAGS for "ferrite machining". > > >>> regards, > >>> Bob > > >> Diamond rotating saw disk?? > > >it's a ceramic;grinding can introduce stress fractures(cracks). > > It is closer to an epoxy bound sintered matrix than a ceramic. > Ceramics get post sintering firings that harden them further. Regular ferrites aren't resin-bonded. You can get resin-bonded soft and hard ferrites and, but the resin dilutes the magentic material and the magnetic performance is consequently poor. You may have only intended to claim that soft ferrites are relatively soft as sintered materials go, but to claim that regular ferrites are expoxy bound sintered matrices is simply wrong. > Machining with striking tools like a lathe bit or mill head cutting > flute/tooth will CERTAINLY introduce fractures. > > Grinding is the ONLY 'correct' type of machining to remove media from > them. They are not 'fired' like a ceramic and do not have the hardness > that a ceramic acquires... AT ALL. They ARE too hard to machine, but > they are not too hard to grind media from. Sintering depends on the same process of solid state diffusion that makes ceramics hard, but managanese-zinc and nickel-zinc ferrites aren't ceramics -inorganic non-metallic solids - and shouldn't be expected to have similar properties, or to react to heat treatment in the same way. -- Bill Sloman, Nijmegen
From: MooseFET on 12 Jun 2010 12:20 On Jun 12, 11:48 am, BlindBaby <BlindMelonChit...(a)wellnevergetthatonethealbumcover.org> wrote: > On Fri, 11 Jun 2010 20:24:34 -0700 (PDT), MooseFET <kensm...(a)rahul.net> > wrote: > > >On Jun 12, 1:33 am, Bill Sloman <bill.slo...(a)ieee.org> wrote: > >[...] > >> Wrong. Permeability drops with rising temperature, and leakage flux > >> rises. Ferrite cores don't have to get very hot before they become > >> magnetically insignificant. Read the relevant data sheets for the > >> material used to make your core on the manufactuere's web site. > > >This has nothing to do with the reason to watch the temperature rise. > >It is just plain a mechanical issue. The material is brittle and a > >bad > >conductor of heat. > > And grinding it doesn't hurt it at all. It got heated when it got > made. It is a sintered, stamped, baked manufacturing process. All sintered things are brittle. Watch the temperature.
From: MooseFET on 12 Jun 2010 12:24
On Jun 12, 11:39 am, BlindBaby <BlindMelonChit...(a)wellnevergetthatonethealbumcover.org> wrote: > On Fri, 11 Jun 2010 20:20:54 -0700 (PDT), MooseFET <kensm...(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. > > Are you trying to say that the particles "meld" together at the > grinding site? The problem isn't one of melting together. It is one of the thing becoming multiple bits of broken material. Since the rest was insulting I removed it. The OP wants to cut a groove into a rod. |