I’ll get those to you tomorrow. I’m exhausted so I’m not hopping back on my PC tonight. The ferrite sheet is in the BOM which is in the documentation GDrive for the project and it will be the same size as the white silkscreen on the bottom of the PCB. If anyone wants to add to the documentation feel free, it needs some more work and cleaning up while we wait for the materials to arrive.
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Fair enough. Ill get your design quoted out tomorrow.
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I’ve placed the order for the plates!
Going to try to figure out something for the ferrite plates but help is welcome
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This is the shape we need to make in the ferrite. Here’s the product listing with documentation. I think your concerns about cutting it may be valid because it appears to be a hard ferrite plate rather than a soft ferrite pad. The density is ~5g/cm3 and mild steel is ~7.85g/cm3. It looks like it will need to machined instead of just cut out like a cookie cutter. I don’t think we can use a laser cutter though because it will sinter the ferrite together weirdly at the edges of the cuts and deform the plate which will disturb the field mechanics.
Bodybytesv1-0_Ferrite[Drawing].pdf (87.4 KB)
Bodybytesv1-0_Ferrite.zip (5.0 KB)
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Hmm. Is that going to be ok for an implant? I’d be concerned it would crack overtime
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The bodybytes will be encapsulated in biocompatible uv cured resin, and if you review the dimensional drawing you can see that the final ferrite configuration is very small which means less leverage. There won’t be much flexing due to rigidity of the resin, and the ferrite being a plate actually makes it much stronger. It will also be much more resistant to thermal expansion than a soft ferrite.
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That’s absolutely beautiful!
Nothing like the awesome feeling of getting something back from the fab!
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I DM’d you the tracking link, plates should be there wed!
I’m still waiting to hear back from the manufacturer on the ferrite plates
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Ordered all the parts today, much success. It was $1900 
Jammy heard back from the ferrite manufacturer and they need to be waterjet cut. We’ll see if we can get that worked out. The plates are only 53 x 53mm and we only need small cutouts so if anyone has access to a wazer lmk
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I’m not sure of your working conditions, could you use an alternate material? I recall Amal having a Glowforge…
Most metals won’t cut.
Acrylic would melt.
If the jig is one off, what about wood? Or the fiberglass substrate that PCBs are made of?
Would it even be possible / cost effective to buy the jigs from a PCB manufacturer (cut to shape, but no traces?)
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Returned it when it couldn’t maintain zero on templates.
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It has to withstand high temperatures. So wood might turn into charcoal…
Fabs can easily cut out shapes, but more complex milling operations could be tricky. Provided, some can do that, Prusa uses milled pockets for the magnets on their printer beads for example. Or at least I think that the fab is doing the milling for them.
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Jammy already sorted out the assembly jigs. They needed to be aluminium so I could put them in the reflow oven and they would transfer heat into the PCB to melt the solder.
Now we’re talking about the ferrite sheets that improve the performance of the wireless charging. I can’t use an alternate material for those, their material properties are important for the magnetics. We can’t use a laser even a strong one because if it does cut it will fuse the edges together which will change the magnetic properties and deform the cut dimensions. I’m talking about using a waterjet or its benchtop equivalent a “wazer” because the material is so small and softer than steel. Jammy has a plan for that too, but I’m open to other options that may be more convenient.
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Ah, that’s my confusion. I thought wazer as in wazer wifle. 
Couple that with the previous no laser on ferrite, and you can see how that leads to my state of misunderstanding.
But as long as I’m here… Long term, would it be more effective to get a punch / die set made? I’m sure it greatly matters what your scale of operation turns out to be.
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Unfortunately a punch and die won’t work because the ferrite we’re using are sintered plates that would crack apart. I didn’t realize how hard they were, I’m used to working with soft ferrites. Harder is better for our application though because it won’t develop cracks and will reinforce the PCB. Plus you get more ferrite per ferrite! (magnetic permeability). Jammy kept referring to the assembly jig as a “plate” earlier which probably confused things.
If we do a production run of these where we would need economies of scale the part sourcing and techniques involved in this project will scale well. We’d only ever be making hundreds
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but let me be clear.. i do have a fiber laser and a different CO2 laser cutter / engraver.
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I knew it. No proper Lair is truly outfitted without a big honkin’ L.A.S.E.R.
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