First attempt pressure-casting ferrite parts.
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- čas přidán 22. 01. 2021
- Before getting my pressure chamber working, I decided to see if I could use a vise and a 3D printed compressor to get higher density/quality ferrite parts. The results were mixed.
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Perfect experience 👌
Spray your holder with a release agent, or put some car wax on it before pouring...that might help it separate easier when you de-mold
I'm interested in your progress in this, would you want a kiln to try sintering ferrite in? I'm working on making an arduino-powered PID controller for a kiln at home right now (commercial kilns are expensive as heck, and part of it seems to be that they use a mixture of various off-the-shelf components hacked together)- and I'd be curious to see what results you could get from sintering ferrite with a binder poweder (like nickel zinc). I'd sell one to you at-cost for me (looking something like 200$) or send you my code and wiring diagram if you wanted (designing it for arduino nano).
nice job.
I am making pressure molded stators and found where the my 3d printed molds that using parting wax in combination with a mold release (pva in my case) did the trick. Was this the urethane and iron powder that seemed to work better for you in your other vid?
curious if you pursued this further and have more insights to share. I'm about to try making my own ferrite parts soon. Thanks for sharing!
Awesome, thanks for the tip!
This was polyurethane and iron powder, but I haven't made much progress in this project. I attempted to replace the PLA die with a PVA die that would dissolve in water, but it took several hours to fully dissolve and ended up oxidizing the core. My next plan whenever I decide to actually pick this back up is to machine an aluminium die and compress it with an arbor press.
Perhaps it is time to add other metals to the mix to increase resistance. Manganese and cobalt come to mind, but maybe those are only used in true ferrite, as opposed to metal powder compositions.
Thanks for sharing. Your test bed was very insightful. I am about to embark on this same goal to make custom cores from home. As stated before you need to use mold release to prevent sticking but the print layer lines may also cause trouble. Another approach is to use soluble support material as the mold material liner. Print a thin wall 0.5 mm liner and also print a solid reinforced former with PETG or nylon outside that for strength when pressing. On previous formers like this I tapped threads in the bottom and used a bolt and wrench to remove parts. I was considering using the low viscosity urethane blend and making something like dough with the powder metal and pressing it in the mold. What I was curious about was the purity of the iron powder you used? Also did you consider making blends of 99.9% pure iron powder and iron oxide powder? Or pure metal 50-50 alloy of iron cobalt atomized powder? there are also SMC powder materials that have been engineered for powder cores that have oxide layers around the particulates. I think you were on the right track but you need to keep going. I was also thinking of using thin wall 0.5 mm magnetic PLA as the liner and forget about trying to remove it. This approach might give the highest precision parts with the lowest chance of part failure. Something to use the rest of that spool on. Have fun and please continue this content.
Thanks for your insight, I also am going into making my own cores for making my own brushless motors for servos and both this video and your comment were very helpful. It's because of you hobbyist that I have motivation to do these things. Also which core recipe got you the best results please?
@@JustcsSrvd I'm full time in development of my own motors & generators. Now with more experience with this method I can say that by far the best method Is to use 3D printed Magnetic PLA liners 0.5 -0.8 mm wall thickness. Take the magnetic part you want and shell it to wall thickness with one open end. This also works when you need holes for fasteners as the hole gets shelled. Then make a split compression mold the liner fits into snugly. Bolt the split mold together including any fastener holes. The liner is delicate and needs full support backing. Pack metal epoxy mix into the liner as hard as you can, use a vise if you need to. Make what ever packing tools you need. The compression mold and tools should be solid prints, no infill. Remove part from compression mold as soon as its packed full with no voids. Epoxy will leak out of any micro holes in the liner so you must remove it immediately. Print a wide ring 3-4 mm thick solid to snugly fit the open end of the liner to hold the dimensions. Make sure to bevel one end of the ring to make it easier to slip over the open end without squishing it. Tap the mix to liquefy the epoxy mix and raiser any excess off, then let set for full cure time. The ring will stick a little so tap carefully with a hammer to break the bond and remove the ring. Any excess can be sanded off at this time. For motors and generators they are low frequency, usually around 3KHz or less so Flux density and high resistance are of the greatest importance. I had very good results with Max Cast Hybrid Epoxy Casting Resin with a dielectric breakdown of 500V/mil. The Powders I tried were 99.95% pure iron 325 mesh powder (Its important to get the very highest purity as magnetic properties increase exponentially in the last %) there are several papers on this fact. The other I tried was Somaloy powder that was optimized for low frequency. This preformed very well too but was way more expensive. However it may be worth it with later designs as when press-formed into solid metal and properly annealed it is very impressive in every way. www.hoganas.com/en/powder-technologies/soft-magnetic-composites/ Premix to weight the epoxy (6-12g.) per/batch and mix in powder and work it till you have a ball of playdough consistency wet enough to stick together but dry as manageable. When fully cured I got 15Mohm/cm with the pure iron powder. It was hard to get a good reading as I was getting capacitive charging when I dug the probes in. This will never likely be a commercial solution but It is flexible & effective and will let you test your designs. Please share your experience as I'm eager to hear your results.
@@dee5556 Thank you very much for the information. I was feeling like I wasn't making any headway with the research of the mixes, wondering if I was looking in the wrong place or if those were closely guarded secrets like optical glass.
@@JustcsSrvd Engineered materials are a closely guarded secret involving much expensive R&D like Somaloy and MetGlas but some is university research like pure iron powder and 50-50 pure iron cobalt alloy powder is openly available. The iron cobalt alloy powder has the highest magnetic properties of all but also the highest expense and material availability is limited and controversial. University papers are easier to find than corporate formulas but you might have to donate a bit for it. IMO pure iron powder has the best magnetic properties for the $ and there is no reason for it to be a secret. The biggest problem of course is electrical resistance and material density. For commercial products engineered solutions are the best choice, but for R&D where design comes into play, this works well. If you build a standard motor design with this technique, you can get accurate comparative data with your own design as well as comparative data with a standard motor made with silicon steel laminations. This data is will be valuable for funding as the project progresses.
Oh wow, I didn't even think about using the iron oxide powder mixing prototype as aa control for reference when making my own mixes. You just dropping information on me, thank you again.
Just found some intrest in your works
Also ive seen alot of powerfull mangnets in loudspeakers or etc. Is it possible to make smt like them this way?
What do you mean by smt?
Couldn't you print it in PCL and then melt it off?
Probably. I think the best approach would be to make an aluminium mold with a 3D printed mold liner for easy releasing, and then just melting/dissolving the mold liner off.
PCL might not be ideal due to its low glass-transition temperature, as it might be too soft to hold a shape.
One plastic I have messed with a bit is PVA, which seems decently strong from my experience and is water soluable.