
600 Watt, 3d-printed, Halbach Array, Brushless DC Electric Motor [video] - donquichotte
https://www.youtube.com/watch?v=NFvMC3l3fGY
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nraynaud
We really need a cheap online laser cutting magnetic metal lamination service.
There are more and more online laser cutting services, but they don't stock
magnetic lamination steel. The only online specialized service is incredibly
expensive.

We are in a golden age of electric motors, but access to custom laminations is
a limiting factor for tinkerers (now that the magnet are widely available).

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Declanomous
I think the issue is that anything involving custom magnetics is a niche area
for hobbyists right now. I think most hobbyists and tinkerers prefer off-the-
shelf parts to one-off motors, transformers, inductors, etc.

That being said, I've already seen quite a few videos of people winding their
own magnetics, so perhaps there is a market to be capitalized on.

~~~
nraynaud
no, I think the RC modeling people are quite numerous, and quite into custom
motors, I think they are the ones who made the electric skateboards and
scooters possible, BLDC control was only for serious business before them.
Then, they started rewinding their motors. And after that they started putting
them backwards (outrunners), by recycling brushed DC rotor laminations for the
stator.

But I really feel like the RC community is screaming for custom lamination.
And with them will come the homemade electric car people, skateboards, bikes
and wind turbine, all those tinkerers.

Next step I guess will be the magnets, they will want custom magnets whose
magnetization surface is not planar. And also custom arc circle magnets (for
halbach array pancake motors).

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Declanomous
Interesting, I'm not familiar with the RC market at all. I've looked into
e-bike, electric car, and wind power projects before, and I definitely found
the choice of motors was often one of the most limiting factors. I've followed
projects where people have built there own motors, but I've never seen anyone
build a custom motor using custom lamination. I've seen more motors made out
of wood than I can count though.

Honestly, I think this is one of those things where the market doesn't exist
until it exists. Someone could probably create a market for it by creating
some cool projects in certain fields using custom cut metal lamination. If you
offered to make custom lamination at cost for people who were building their
own projects, they'd end up posting about it, and soon enough people would
realize that you could make things with custom lamination.

That being said, I definitely don't have the technical expertise to judge
whether inexpensive custom lamination is even possible, or if it's one of
those things where you build a super cool company that makes just enough money
to keep you in poverty.

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onmobiletemp
If used for anything substantial, such as an ebike that goes fast or up slight
grades, this motor would simply melt. Its really cool though. A lot of ebikers
fool around with liquid cooling but ive never seen it pulled off. This guy
could take advantage of the 3d printing method to add liquid cooling and
besides being really cool it might allow the motor to do useful work without
melting.

~~~
alkonaut
It must be very application specific what kind of air cooling you get? If you
have a motor enclosed on an e-bike vs. if you have it naked on some kind of
aircraft with a propeller blowing on it must make a huge difference?

A problem I guess with plastic is that it doesn't conduct the heat to the
outside like a metal construction would, so it will always dissipate less than
metal, regardless of environment? That issue is still there if you add liquid
cooling - the plastic won't transfer heat to the cooling medium either.

What's the state of the art in high-temperature resistant 3D-printed
materials?

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Already__Taken
That carbon printer would move the heat around very well.

~~~
dogma1138
Not really, like most micro particle or fiber filaments the thermoplastic
resin is the weak part.

Any thermoplastic extruded filament that does not require secondary treatment
is going to be heat sensitive.

The filaments that are not heat sensitive are either ones that require
substantial heat to extrude in the first place or at then chemically treated
to not be thermoplastics anymore.

If you think about this way it's simple, the melting point and the
thermoplastic point of the end product needs to be substantially higher than
it's operating temperature this cannot be done without additional treatment or
using a process other than thermal extrusion.

Resins that use chemicals or light to harden are can have thermal resistance
properties, metals and other materials that are extruded or bonded at very
high temperatures are also resistant to relatively high operating
temperatures.

~~~
Already__Taken
Makes sense, Although I was trying to infer that the carbon material would
transfer the head through the object better. Which would make using a liquid
cooling channel useful. As opposed to just outright higher thermal operation.

But this is only evidenced from the carbon on my XPS laptop becoming
untouchable in full-sun and much of the base heating evenly from the
processor.

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nanch
The content-vs-time density for this video is extremely high and it was a
pleasure to watch all of the video. I print in PLA rather than ABS right now
so the video isn't directly applicable to my life but it's nice to see
somebody working on the designs. Cheers to the author!

~~~
kelrien
I would recommend PETG instead of ABS next. It is easier to print, the fumes
don't smell as bad and it is a very impressive material mechanically

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Declanomous
Not only do ABS fumes smell bad, they can actually be quite dangerous. I
_believe_ PETG is much safer in that regard.

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Already__Taken
The enclosure looks like it's leaving a lot on the table in terms of cooling
channels and structure. Given the printing can do all kinds of shapes it looks
like it's replicated the kind of body that would come out of a mill or mold.

Are there any printers that can put down glass fibre in the process?

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jononor
The MarkForged 3d-printers can put down carbon or kevlar fiber with Nylon
binder.

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Animats
That's a nice project. The author claims 80% efficiency, which is reasonably
good. Most amateur motor designs are far worse.

The plastic motor shell has a very smooth finish, and _screw threads_. What
process did he use to 3D print those fine screw threads? I didn't think any
available 3D printing process was good enough for that.

~~~
donquichotte
I think he printed an undersized hole, drilled it to the right diameter and
then used a tap to thread it.

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Animats
Look at him screwing on the end bell of the motor at 222 seconds in. [1]
That's a big diameter thread, and the close-ups of it show a very clean
thread. You can see the marks of the 3D printing layers on the outer motor
casing, but not on the thread. I suspect that thread was turned on a lathe.

[1] [https://youtu.be/NFvMC3l3fGY?t=222](https://youtu.be/NFvMC3l3fGY?t=222)

~~~
Aser
I've printed finer threads on my cheap 3D printer, although it took a few
tries to get them the right size.

It's possible that he used acetone vapour to smooth out the surface of the
threads.

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tener
This is very impressive, but keeps me wondering - how is this engine better
than the stuff you can just go and buy in the shop? This is an honest
question, I have no clue what are the benefits here (besides obvious coolness
factor!).

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amelius
We're one step closer to a 3d-printer printing itself :)

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darkwinx
It is already happened I believe. [http://reprap.org/](http://reprap.org/)

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crwalker
I've never understood reprap's cult-like fascination with self-reproducing 3D
printers. This is such an absurdly impossible goal that it's more of a
category error than a current technological limitation: 3D printers are not
organisms with ancestors, they are manufacturing tools. The things that CNC
mills, injection molds, and 3D printers are made _of_ are very different than
the things they _make_.

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Frenchgeek
Well, aiming for the possible isn't as much fun as the impossible.

Also the results are less interesting, usually...

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kaffeemitsahne
What's the type of paper called that he puts on the motor at the 2:15 mark?
Doesn't look like simple iron dust.

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jakeogh
[https://en.wikipedia.org/wiki/Magnetic_field_viewing_film](https://en.wikipedia.org/wiki/Magnetic_field_viewing_film)

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mrfusion
So in brushless motor the outside part with the magnets is the part that
rotates? is that way it's brushless? You don't need to supply electrify to the
part that moves?

Or do I have this all wrong?

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lucaspiller
Exactly, here is a video that explains it:

[https://www.youtube.com/watch?v=bCEiOnuODac](https://www.youtube.com/watch?v=bCEiOnuODac)

Compared to brushed-motors they can be more powerful for the same weight
(which is why they are popular in the RC world), quieter, last longer, and
produce less EM interference.

~~~
Offal_One
The downside being they need powerful rare earth permanent magnets to work,
making their construction more expensive than induction or brushed universal
motors.

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zecken
Impressive on so many fronts, it's so cool what's possible nowadays with
modern prototyping tech. Thanks for sharing!

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lloydjatkinson
I hate the trend that's been going on for a few years now where they try to
imply that _all_ of a given product is 3D printed.

For example this motor is easily 80% metal and copper wire for the poles. The
remaining 20% is the plastic case. That is the 3D printed part. Not exactly
very impressive.

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smoyer
Having built a motor from scratch, I've learned that the hand-winding of the
coils that's impressive. Mine had no torque and was terribly inefficient but
there's a local motor rewinding shop where they produce real art.

