ferrite machining?
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From: Mike Harrison on 11 Jun 2010 12:21 On Fri, 11 Jun 2010 05:42:19 -0700 (PDT), Yzordderrex <powersupplyguy(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. > >regards, >Bob Ferrite is pretty much like ceramic, so you're talking grinding, preferably with diamond
From: BlindBaby on 11 Jun 2010 12:43 On Fri, 11 Jun 2010 17:21:56 +0100, Mike Harrison <mike(a)whitewing.co.uk> wrote: >On Fri, 11 Jun 2010 05:42:19 -0700 (PDT), Yzordderrex <powersupplyguy(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. >> >>regards, >>Bob > >Ferrite is pretty much like ceramic, so you're talking grinding, preferably with diamond Yep. Not nearly as hard as ceramics are. Not even as hard as your kitchenware actually. Fairly crumbly even, by comparison. But yes, grinding is the only way to remove media from these components because any machine tool application may shock the remaining media, causing unseen microfractures (or seen) that damage the operational characteristic of the media. If the rod is the center piece for a closed loop core, then the mating ends have to be kept smooth and should not be touched at all. The coupling at that interface is important. If it is an open ended transformer that does not have a closed loop core, I cannot see how trying to top out some efficiency by this primary placement even matters. Put it on top of the secondary. If isolation is the issue, put the primary inside a Teflon tube, if the turns count is low enough. There certainly is no 'major' efficiency to be gained by tightly mating the primary wire to the core. Especially if it is an open ended core configuration. Or maybe that is why it DOES have to be tight. It is so lossy that he needs it that close. If that is the case, this situation should be using a fully closed loop pot core or C-I core or the like.
From: Bill Sloman on 11 Jun 2010 13:33 On Jun 11, 6:07 pm, 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. 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. -- Bill Sloman, Nijmegen
From: BlindBaby on 11 Jun 2010 14:43 On Fri, 11 Jun 2010 10:33:17 -0700 (PDT), Bill Sloman <bill.sloman(a)ieee.org> wrote: >On Jun 11, 6:07�pm, 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. > >Wrong. You are wrong. An overheated magnet will lose some of its magnetization level after it cools. An overheated ferrite core will have the same characteristics after it cools. > Permeability drops with rising temperature, and leakage flux >rises. But getting it hot while grinding it does not hurt it once it cools down, idiot. Nobody said anything about heating it in circuit. > Ferrite cores don't have to get very hot before they become >magnetically insignificant. The temp is upwards of 200 to 600F, dipshit. > Read the relevant data sheets for the >material used to make your core on the manufactuere's web site. Again, applying a thermal precaution to a grinding operation is NOT required. The medium remains unchanged after the grinding is completed. It is the same *when it is at room temp* before grinding, as it is *when it is at room temp* after severe heating has been introduced from having been ground. Nobody said a goddamned thing about it being hot during operation or while in use. Learn to read, dumbfuck.
From: Bill Sloman on 11 Jun 2010 17:54
On Jun 11, 8:43 pm, BlindBaby <BlindMelonChit...(a)wellnevergetthatonethealbumcover.org> wrote: > On Fri, 11 Jun 2010 10:33:17 -0700 (PDT),Bill Sloman > > <bill.slo...(a)ieee.org> wrote: > >On Jun 11, 6:07 pm, 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. > > >Wrong. > > You are wrong. An overheated magnet will lose some of its magnetization > level after it cools. An overheated ferrite core will have the same > characteristics after it cools. True, but not what you said. > > Permeability drops with rising temperature, and leakage flux > >rises. > > But getting it hot while grinding it does not hurt it once it cools > down, idiot. Nobody said anything about heating it in circuit. Again true, but - again - not what you said. > > Ferrite cores don't have to get very hot before they become > >magnetically insignificant. > > The temp is upwards of 200 to 600F, dipshit. The managanese-zince ferrites that we use for frequencies up to about a 1MHz have Curie points between 125C and 150C - 260 to 300F. Nickel- zinc ferrites for higher frequency work can have higher Curie temperatures - Philips listed one (good to 50MHz) that had a Curie point above 500C - 900F - though another crapped out at 125C. 150C isn't impossibly hot for some kinds of working circuits. > > Read the relevant data sheets for the > >material used to make your core on the manufactuere's web site. > > Again, applying a thermal precaution to a grinding operation is NOT > required. The medium remains unchanged after the grinding is completed.. Correct. > It is the same *when it is at room temp* before grinding, as it is > *when it is at room temp* after severe heating has been introduced from > having been ground. > > Nobody said a goddamned thing about it being hot during operation or > while in use. On the other hand, you didn't phrase your comment to exclude those situations. > Learn to read, dumbfuck. Learn to write in a way that doesn't make claims that you didn't intend. -- Bill Sloman, Nijmegen |