ferrite machining?
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From: BlindBaby on 11 Jun 2010 20:47 On Fri, 11 Jun 2010 19:25:07 -0500, Jim Yanik <jyanik(a)abuse.gov> wrote: >Sjouke Burry <burrynulnulfour(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. 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.
From: MooseFET on 11 Jun 2010 23:20 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.
From: MooseFET on 11 Jun 2010 23:24 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.
From: BlindBaby on 11 Jun 2010 23:39 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. Are you trying to say that the particles "meld" together at the grinding site? Well, they don't. It is mostly abrasive cutting, per se, not so much grinding like one does when trying to make a bar of steel shorter or the like, THAT heat soaks in and remains and builds and burns of the metal and annealing/hardening cycle occur. This ain't a steel bar. It grinds far easier, and it does not build much heat because it grinds easier. I have modified more pot cores for production than you have likely ever seen in your life. I know exactly how easy it is to work and what tools are best to work it with. You likely do not know what the word 'work' means since you are so paranoid about thinking that it would soak up so much heat or even have local heat issues when it will not. It would not change anything even one ten thousandth of one percent if it did, which it doesn't, and that would only affect the are ground. It does not happen, and your paranoia is nothing more than a fantasy... of yours.
From: BlindBaby on 11 Jun 2010 23:48
On Fri, 11 Jun 2010 20:24:34 -0700 (PDT), MooseFET <kensmith(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. |