/robowaifu/ - Actuators For Waifu Movement Part 3

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Actuators For Waifu Movement Part 3 Kiwi 12/06/2023 (Wed) 01:18:16 No.27021

(1stl thread >>406 2nd thread >>12810) Kiwi back again with a thread for discussing actuators to move your waifu! Part Three! Let's start with a quick introduction to common actuators! 1. DC motors, these use brushes to switch the ferrous core electromagnets on a rotor to rotate its magnetic field relative to surrounding magnets! They're one of the cheapest options with an average efficiency range of 30 to 90%. Larger DC motors and motors with higher turn counts are more efficient. 1.5 Coreless DC motors, by removing ferrous materials, losses from hysteresis are almost eliminated, dramatically increasing efficiency to nearly 90% even in small motors. Eliminating the ferrous materials reduces flux focusing, resulting in weaker fields and higher speeds. 2. Brushless DC motors (BLDC), these use a controller to switch the electromagnets on a stator to rotate the magnets of a rotor! Without brushes, they have the potential to be more efficient with higher power density compared to DC motors. Their efficiency and behavior vary depending on the algorithm and sensors used to control them. Coreless brushless motors exist but are rare and only used for very niche applications. 3. AC motors, a wide and incredibly varied category. They all rely on AC’s frequency to control them. With single phase AC motors relying on shaded poles, capacitors, or some other method to induce a rotating magnetic field. 3 phase AC motors naturally have a rotating field which usually gives them higher efficiency and power density. Notably, most AC motors are brushless. The most commonly used brushed AC motor is the universal motor, which is 4. Stepper motors, brushless motors with ferrous teeth to focus magnetic flux. This allows for incredible control (stepping) at the cost of greater mass, subsequently giving them higher rotary inertia. Usually 50 to 80% efficient depending on control algorithm/speed/and quality of the stepper. Due to their increasing mass production (& ubiquitous low cost controllers), they have appeal as a lower cost alternative to BLDC motors if one carefully designs around them. 5. Coiled Nylon Actuators! These things have an efficiency rating so low it's best to just say they aren't efficient. (0.01% typical, 2% achieved under extremely specific conditions in a lab.) Though they are exciting due to their incredible low cost of fabrication, they’re far too slow and the energy requirements are nonsensical. https://youtu.be/S4-3_DnKE9E https://youtu.be/wltLEzQnznM 6. Hydraulics! These rely on the distribution of pressure in a working liquid to move things like pistons. Though popular in large scale industry, their ability to be used in waifu's has yet to be proven. (Boston Dynamics Atlas runs on hydraulics but it's a power guzzler and heavy) Efficiency varies wildly depending on implementation. They would work great for a giantess! 7. Pneumatics, hydraulics lighter sister! This time the fluid is air! This has the advantage in weight. They aren't capable of the same power loads hydraulics are but, who wants their waifu to bench press a car? (Too loud and inefficient for mobile robotics.) 8. Wax motors, hydraulic systems where the working fluid is expanding melted (commonly paraffin) wax! Cheap, low power, and produce incredible forces! Too bad they're slow and hard to control. 9. Explosion! Yes, you can move things through explosions! Gas engines work through explosions! Artificial muscles can be made by exploding a hydrogen and oxygen mixture in a piston, then using hydrolysis to turn the water back into hydrogen and oxygen. None of this is efficient or practical but it's vital we keep our minds open! Though there are more actuators, most are derivatives or use these examples to work. Things like pulleys need an actuator to move them. Now, let's share, learn, and get our waifu moving! Servos! These use an actuator and sensor to control motion. DC, coreless DC, and BLDC motors are the most commonly used actuators for servos in mobile robotics. Potentiometers or hall effect sensors are the most commonly used sensors to detect rotary motion in servo systems. >Soft muscles (pneumatic system) with origami-inspired skeletons: https://youtu.be/OJO4FP0DXgQ[ >Printed pneumatics (TSA can also be used instead of pneumatics for actuation.) https://youtu.be/_X0rDW6NQ58 >Using sugar as soluble support material for printing silicone muscles: https://youtu.be/L0Z0-y3qpNk >Cavatappi artificial muscles (hydraulic coiled nylon hybrid): https://youtu.be/yXAJGH5s4cs https://youtu.be/MpCFumHFZvU https://www.designnews.com/automation/cavatappi-robot-muscles-have-5-times-strength-human-muscles >Twisted string actuators (TSA) Be extremely careful when choosing your strings. They will be put under extreme strain and must be durable. https://youtu.be/N4VMoYFrusg https://youtu.be/hFuzQ4ed-t0 https://youtu.be/J26y1nn7JMM https://youtu.be/zYrHGMiqC9A https://youtu.be/PABVsuV7Y1M https://youtu.be/tP9B3aqc4CI https://youtu.be/Y1uceDzhjKY >Continuous ransmission (CVT) / torque converters https://youtu.be/kVPjhmTThPo https://youtu.be/cd2-vsTzd9E https://youtu.be/c9e2y-5DMNc https://youtu.be/PEq5_b4LWNY >=== -edit subj

Edited last time by Chobitsu on 12/06/2023 (Wed) 03:06:55.

Chobitsu 05/10/2025 (Sat) 07:41:00 No.38338

>>38336 POTD >At large scales, the costs of materials adds up, making reluctance motors attractive. You encourage us all, fren Kiwi. Cheers. :^)

Grommet 05/11/2025 (Sun) 04:54:18 No.38367

>>38336 >The material naturally has some reluctance, which is beneficial for controlling rotor position, but also reduces the speed at which the rotor can react to changes in the stators flux Ok I do get that. Makes sense. >difference in costs between a coreless motors magnets and a switched reluctance motors electrical steel sheet rotor are enormous ehhhh...I don't buy that. Yes this used to be true. Every time you see any article on pure reluctance motors they always bleet on about the control system but you can get microprocessors for 50 cents now or ones with more outputs that are less per drive and the transistors to drive them cost much the same for either. I'm not saying it's not more difficult to set up but once you do, I think the cost is way less. If I'm not mistaken most appliances the major motors have all moved to some form of reluctance drive because...cost. I think there's just way fewer people that can easily design reluctance drives. I never said it was easy, so therefore, there are less of them. Most car manufacturers are,likely, moving towards reluctance drives with some, a magnet here and there. >50,000 RPM and stop in milliseconds. I am impressed by this. Most of the electric motors I have dealt with were larger and couldn't dream of doing that on their best day. >a type of steel you correctly guessed is high in silicon Not a guess. Some are made of different alloys but the cheapest and most common is high silicon iron. I "think" there may be a way to use the high inductance in the Stator. The idea is to have not coils but sheets of aluminium. By using pulses of electricity into them combined with high inductance (the sheets are mixed up with the iron sheets/powders) you could have a lost cost system easy to put together. Winding coils is time consuming, costly and tedious. If you notice I went on and on about Don Lancasters "magic sine waves". Basically pulses adding up in a circuit to give you sinusoidal waves.Or maybe I didn't. I thought I did but I did provide a link. >>27823

Grommet 05/11/2025 (Sun) 04:58:20 No.38368

>>38336 >coreless motors magnets and a switched reluctance motors electrical steel sheet rotor are enormous I read that wrong you are correct.

Kiwi 05/14/2025 (Wed) 17:49:39 No.38485

>>38367 Good demonstration on how to build your own switched reluctance motor. https://www.youtube.com/watch?v=UFf304FkbiQ

Chobitsu 05/14/2025 (Wed) 21:01:30 No.38501

>>38485 Neat! I learned a lot just watching this about SRM. In a factory setting, we'd likely have our own laser cutters & jigs for assembly, etc. So, eventually we'd pretty much get down to just the marginal costs involved. I'm no expert here, but these seem to me to be fundamentally cheaper than more-typical electric motors of a similar capacity? <---> This guy seems pretty clever! Though he does need to learn a few things about his personal health & safety. And lighting for better f-stops! :D Nice find, Kiwi. Cheers. :^)

Kiwi 05/14/2025 (Wed) 22:35:33 No.38504

>>38501 It'd be trivial to mass produce 'em with a hydraulic die press, and a few jigs with simple sensors and steppers. Though, it'd take heaps of time and money, while requiring a shop for us to work out of. Even then, we'd need to make millions before breaking even relative to just buying BLDC motors and their respective systems. I still think it's worth keepin' in the back of our minds for when we have the capitol to make thse kinds of moves. Someday, I want to run a factory filled with waifu and anons buildin' waifu.

Robowaifu Technician 05/14/2025 (Wed) 22:38:02 No.38505

In terms of keeping cost down, what are some powerful motors that could be salvaged from a junkyard but also useful for building a robowaifu? I hear windshield wiper motors are pretty good and you can get them for next to nothing at junkyard yard.

Kiwi 05/15/2025 (Thu) 01:08:31 No.38507

>>38505 >Windshield wiper motors They have some complications but, are a fantastically high torque motor, relative to cost, https://www.youtube.com/watch?v=D7hkFh4uhMo&t=69s https://www.youtube.com/watch?v=3pYWLF8qw-g

Chobitsu 05/15/2025 (Thu) 04:04:24 No.38508

>>38504 POTD >Even then, we'd need to make millions before breaking even relative to just buying BLDC motors and their respective systems. Hmm. Makes sense. OTOH, your """favorite""" Afrikaner says they plan to roll out billions of Optimus's. So yeah, if we here hit it out of the park on behalf of the little guys, then I don't think millions is out of reach. It's certainly my dream already! :^) <---> >Someday, I want to run a factory filled with waifu and anons buildin' waifu. I LIKE THE WAY YOU'RE THINKING, ANON! This has been my dream for years now. Ultimately, I want to help Anons all over the world. But until that blessed day comes fully to fruition, I want to help the Anons of /robowaifu/ first & foremost. I'm trying to understand how to organize (smol, to start out with): * Obtaining basic-bey*tch funding (the 'find out fee' tier of cash) for the startup * Robowaifu construction facilities * Housing for staff (room & board) (temp. or perm., depends) * Transportation for relocation (temp. or perm., depends) * Unraveling the tangle of legal, &tc., bureaucratic red tape... Keep.Moving.Forward. Cheers, Anon. :^)

Chobitsu 05/15/2025 (Thu) 04:11:26 No.38509

>>38504 >That Sukabu tho... Normally, I don't care for such depictions of robowaifu gore; its personally offputting to me. But he is so skilled, and his depictions so tasteful, that I actually find them to be charming instead! :D <---> I sure hope he'll begin doing highly-technical breakdowns of his joints concepts (exploded-views, parts-breakdowns, range-of-motions, etc., etc.) The man has amazing talents as a concept artist! * Thanks & cheers, Anon. :^) --- * I hope we can actually hire him someday to visualize our robowaifu lines for ad-copy/propaganda/technical-manuals/&tc ! :D

Edited last time by Chobitsu on 05/15/2025 (Thu) 04:24:39.

Grommet 05/31/2025 (Sat) 08:42:50 No.38868

Interesting paper. Dielectric elastomer transducers with enhanced force output and work density https://sci-hub.ru/10.1063/1.4730953 The glitch on DE is the need for high voltage and low force per weight. I saw another paper where they talked about 0.73N-M/Kg. That sucks. Like 0.5 foot pounds of force per Kg. The paper above describes DE's that use less voltage and high permeability nano-powders to increase force. I have some troubles with the paper as the units are not clear to me what they mean. They say 705 mN blocking force...so per what volume or weight??? They also use the unit V/uM which I don't understand. Is this the volts per thickness??? This system of units volts per area has never been clear to me. 705 mN is still not a lot of force. as above 0.5 ft-pounds or so. I wonder that there could not be some way to combine this with hydraulics using the DE materials as switches. A major problem, or I think it is, is that all these coils for electromagnetic actuators are hard to wind and take expensive copper wire. If you could use DE at lower voltages and combine with some other actuation force it could cut cost and complexity of manufacture. There's another good paper on DE's that's a sort of survey, "Multi-functional dielectric elastomer artificial muscles for soft and smart machines " https://sci-hub.ru/10.1063/1.4740023 These DE's sound soooo good but when you look in to them the drawbacks really add up.

Chobitsu 05/31/2025 (Sat) 18:27:52 No.38874

>>38868 Ehh, don't be too discouraged about it, Grommet. IMHO, it's simply a matter of the misdirecting of goals. If one is trying to run main-force actuators (shoulders/hips, elbows/knees) with this then sure...probably quite insufficient to the tasks. OTOH, using these for something like facial animation, or perhaps even finger actuation, or pleasing volume deformations (as in muscle flexures, etc.) then these might be just the ticket today! <---> Regardless, I'm glad research is moving forward for this tech. Who knows but that they may make some breakthrough with it soon-ish? Cheers, Anon. :^)

Grommet 06/14/2025 (Sat) 01:42:45 No.39236

What appears to be a good paper. Good review of soft magnetic materials. You would want to know this as it pertains to any sort of electric actuator or motor. On the link http://zhao.mit.edu/all-papers/ you find the paper Yoonho Kim*, Xuanhe Zhao*, Magnetic Soft Materials and Robots, Chemical Reviews 122 which can be downloaded from there. He has lots of papers on robotics.

Chobitsu 06/14/2025 (Sat) 01:43:12 No.39237

>>39224 Thanks, Grommet! Nice resource. Cheers. :^)

Chobitsu 07/01/2025 (Tue) 00:10:31 No.39677

>>39674 Naicu, thanks GreerTech! :^) My instincts tell me you'd need at least a 30cm - 45cm wingspan (ala the Giant Dragonflys) to lift up, say, a Barbie -doll-sized Aoki Lapis.

GreerTech 07/01/2025 (Tue) 00:16:20 No.39678

>>39677 Thought of the Wowwee dragonfly toy. Then I remembered a website I used to browse as a kid had a teardown of one. @Hik take notes! https://www.societyofrobots.com/misc_wowwee_dragonfly.shtml @Hik , as a former kid who used to be obsessed with toy helicopters, my advice is: styrofoam and thin plastic is your friend

GreerTech 07/01/2025 (Tue) 00:30:58 No.39680

>>39678 Images from the site Linked Video: https://youtu.be/-cU05nsF2BQ?si=0nD4zEcEVVg1zrW7

Chobitsu 07/01/2025 (Tue) 01:40:32 No.39682

>>39678 >>39680 POTDs That's freakin' cool GreerTech! Hadn't heard of these before. This is very close to just the size I was imagining would be needed for a smol Lapis fairybot robowaifu. >rotary motor driving cranked wings Neat! Cheers, Anon. :^)

Edited last time by Chobitsu on 07/01/2025 (Tue) 01:42:38.

Chobitsu 07/01/2025 (Tue) 23:32:39 No.39694

Smol(r) if true >This mechanism shrinks when pulled https://www.youtube.com/watch?v=-QTkPfq7w1A

Grommet 07/05/2025 (Sat) 13:21:57 No.39779

A good video on "Switched reluctance motors Presence, past and the future" https://www.youtube.com/watch?v=xlfhUT8OtxY It's a quick overview. The real meat I'm looking at is the high efficiency , low cost and low weight per power that is covered. This same sort of tech is also relevant to all sorts of actuators if designed to make use of reluctance forces (magnetic materials attracted to electrical coils). They talk about IPM motors what this is is magnet motors and they mean with rare earth magnets. In cars I think rare earth will go the way of the Dodo. Tesla only uses a few smaller ones that, I'm guessing, even out ripple and give it a little more low speed torque. They could easily do without but I think they are looking for max performance. it would not surprise me that ion the future they would tune their motors a little more and do without them all together.,

Grommet 07/05/2025 (Sat) 13:25:26 No.39780

Here's a decent paper I found on much the same Switched Reluctance Motor Research Trends and Overview-Jin-Woo http://www.cestems.org/uploads/20181225/15457069342055.pdf

Толкач 07/05/2025 (Sat) 20:19:27 No.39790

Grommet, mate - just wanted to reply to your post, but in the relevant thread. Regarding pneumatics running hotter - you're absolutely right, as far as waste heat is concerned; I should've clarified what I was referring to by running cooler - the actual robowaifu (aside from the powerplant) will run cooler. :) With pneumatics, the heat is primarily trapped within the tanks, and the pump. With hydraulics, the actual lines and actuators end up heating excessively. Again, I'm certainly no engineer - so you most definitely know more than I do.

Толкач 07/08/2025 (Tue) 01:23:44 No.39824

>>39790 Continued, for Grommet. Mate, I was doing a bit of thinking - string tendons are a pretty appealing option, aren't they? I mean, provided, the biggest disadvantage is hysteresis - the tendons may stretch, shift out of alignment over time (needing to be recalibrated), or tear - and repair might be a bit complex. But, control is easy, motors can be housed quite a distance from the actual joint (permitting smaller joints), and, by using a non-compliant medium (metal cable versus pliable materials), we could keep stretching, tearing, and wear to a minimum. Limit switches in larger joints might make recalibration easy - alternatively, manual recalibration, which would give a margin of error that allows for a few millimeters of stretch - that should last a few years, I would think. Direct-drive for larger joints, and cable-drive for smaller ones? I've got a Chinese contact that can provide piles of cheaper servos - smaller components, and, it'd be easier to gear them, if we aren't as concerned with gearbox size - opens up quite a few options with using larger motors, too. Correct me if I'm wrong, but, with single-automata scale millwork (belt & pulley systems), complex movements of single joints can be achieved with greater ease. With a single tendon per finger, you could, fairly easily, contract all finger joints using a single servo. Again, I don't know the first thing about robotics - so, if the idea is asinine, I do apologize. But, I could reach out to my guys and see if they could source small pulleys, belts (high-rigidity, low-elongation / low-expansion), and servos. I'll bring my own 3D printer to life, and try to make a prototype, if that'd be helpful.

Grommet 07/09/2025 (Wed) 13:25:52 No.39852

>>39824 >Mate, I was doing a bit of thinking - string tendons are a pretty appealing option, aren't they? Yes they are and will likely be a part of any design. The way to get around stretching is not pay attention to it at all. You use the "position" of the joints for reference and position feedback. That way they stretch, so what, you just pull a little more til the joint lines up to where you want.

Robowaifu Technician 08/04/2025 (Mon) 21:48:05 No.40123

hip motor https://robstride.com/products/robStride04 Should be enough for a 4 feet 20kg robot you can downgear motors but theyll be bulky

peteblank 08/06/2025 (Wed) 14:39:00 No.40128

>>40123 Hold the phone There are planetary gearboxes for the nema 23 stepper motor that can be geared down 50:1 I can’t believe nobody has pointed that out that’s the solution right there

Robowaifu Technician 08/14/2025 (Thu) 06:36:35 No.40288

> (actuators -related : >>40272 )

peteblank 08/16/2025 (Sat) 23:14:08 No.40335

I got some good news. I found the winning combo. The 895 dc with a gear box. The 895 dc rated torque is 0.4 nm. But were not interested in that. We’re interested in the stall torque. So you see its not 0.4 nm its 1 nm and well get that every time cause torque is at its peak when it starts and the walking happens in 1 second intervals or so. So when you see a gear box whatever gear ratio it has that'll be the final torque roughly just taking up a few cm if space.

Chobitsu 08/17/2025 (Sun) 00:04:56 No.40336

>>40335 Glad to hear it, Anon. What's the best price you can find for such a combo?

peteblank 08/17/2025 (Sun) 02:33:00 No.40339

>>40336 Like $15

Grommet 09/26/2025 (Fri) 10:18:44 No.41897

Book on magnetic materials for actuators "Magnetic Soft Materials and Robots" https://annas-archive.org/md5/431d67b7d6bc0c93a38f7f87014c6a40 For clarity, soft materials are materials that are attracted to magnetic fields or allow magnetic fields to flow through them with low impedance, or that's the way I understand it.

Chobitsu 09/26/2025 (Fri) 11:32:27 No.41899

>>41897 Glad to see you Grommet! Magnets: how do they work? Cheers, Anon. :^)

Chobitsu 10/03/2025 (Fri) 00:56:42 No.42030

>"3D Printed Magnetic Wobbling Gearbox with CV joint" https://hackaday.io/project/169310-3d-printed-magnetic-wobbling-gearbox-with-cv-joint

Kiwi 10/14/2025 (Tue) 17:59:06 No.42261

This video is a good example of why voice coils and solenoids aren't used at larger scales. The current involved quickly get out of hand. You'd need a method to lock the position with exact precision, using little current, without resisting motion when disengaged to make them truly viable. https://www.youtube.com/watch?v=Y3h0vZ2PYl8

Chobitsu 10/15/2025 (Wed) 00:41:09 No.42267

>>42261 Can't stand listening to sodomites, but because you're recommending it I "listened" to it on mute. Unfortunately for me, the jewgle AI must not like it either because it refused to autogen English captions. Can you (or some other'non) expand on the video's content further please? --- AFAICT from your post, your position is that we need perfect, tiny little brakes to lock all the skellington's elements into proper places (and very dynamically!) -- but at a level currently seen as infeasible to produce rn. Is that it? I presume the primary point being, is that the current drain through the coils to do so otherwise is exorbitant?

Edited last time by Chobitsu on 10/15/2025 (Wed) 00:49:18.

Grommet 10/15/2025 (Wed) 06:33:15 No.42277

Another interesting book. "Soft Magnetic Composites in Novel Designs of Electrical Traction Machines" https://libgen.li/edition.php?id=154146771 Why? If you are going to DIY motors the easiest, in my opinion, way to add permeable material to guide the magnetic fields is using some sort of powdered permeable material and binding it with epoxy or other means. You can mold this however you like easily. The other option is silicon steel(and lest not even take about metglass). It comes in sheets, must have some sort of insulating layer between them. You will likely have to punch them out as they are brittle and availability is not so good. It's my opinion that these guys want to sell you a ton at a time and are not interested in small lots. If you're a big industrial appliance maker maybe it makes sense but it has disadvantages for the DIYer. Now scratch all I said(or maybe not). I was reading the book and quote, "...• Limited geometrical size of the available parts From the viewpoint of magnetics, the relative permeability of insulation layer around the iron particle is close to air. Therefore, the unsaturated magnetic permeability and saturation ﬂux density of SMC are much lower than that of electrical steel. For the same reason, the SMC are not suitable for the electrical machine requiring high magnetizing current such as reluctance machine..." Damnit...why doesn't other sources point that out right away? I read a lot of stuff on this and practical advice is always missing. People fill up pages of equations which really are not decipherable off hand. Sigh. Have to read more. Maybe by using the capability to spread out you can use smaller permeable flux capacity but over a larger area. The advantages of powder in molds is very great. He has a graph, figure 1.2, that actually shows much different from the death sentence he proclaims. Really good electric motors/actuators are HARD, (says Barbie). I'll see if I can link to trash with the graph. What am I missing. It seems to me that yes, electrical steel is better but the powdered permeable material is not far off. >>1320

Grommet 10/15/2025 (Wed) 06:34:24 No.42278

The link above did NOT work I will try the whole url https://trashchan.xyz/file/a484ceb2599810efaf094aabec2f49817ea7e07b6dc17c4af99e25294e2416d9.png

Chobitsu 10/15/2025 (Wed) 06:39:45 No.42279

>>42277 Thanks Grommet! I still hope we can devise our own actuator winding machines. Improving the magnetic fluxes too would be awesome. Cheers. :^) >>42278 Follow the instructions up in that thread's OP's "protip" note there, is what I do. https://trashchan.xyz/robowaifu/thread/26.html#1320

Grommet 10/15/2025 (Wed) 06:42:14 No.42280

BTW the book IS about using soft magnetics in motors so...should be some enlightenment there and I noted before that, "Tesla 3 motor output = 258KW(345HP) at 27.99Kg(60lbs.) 302 lb-ft of torque but a human rarely puts out more than 400 watts in peak. https://en.wikipedia.org/wiki/Human_power So the tesla motor puts out 4300 watts/pound and human puts out(at 250watts and 200lbs.), 1.25 watts/pound" So we have a LOT of room to make the power we need without going to exotics like Tesla.

Chobitsu 10/15/2025 (Wed) 07:51:03 No.42281

>>42280 Yeah, that's a remarkable dichotomy there. BTW, I remember some'non here posted a video explaining the complex flux modelling that Tesla did for their motors. While they're not unique in this, still I personally find such design work remarkable. IIRC, there's another one showing how amateurs can take advantage of this as well. Metal 3D-printing the flux guides, maybe?

Edited last time by Chobitsu on 10/15/2025 (Wed) 07:52:18.

Grommet 10/15/2025 (Wed) 14:47:03 No.42284

Speaking of 3D metal printing I ran across this paper. "Hydrogel-Based Vat Photopolymerization of Ceramics and Metals with Low Shrinkages via Repeated Infusion Precipitation" https://advanced.onlinelibrary.wiley.com/doi/epdf/10.1002/adma.202504951 As I understand it they are 3D printing a hydrogel I believe like resin printing, then they infuse metals creating nano metallic parts. They burn out the gel and you have a VERY strong metal part. If not fake or too complicated this could be a big breakthrough. With just a 3D resin printer and a high temp oven of some sort you could make high quality metal parts with high accuracy. One of the ideas I came up with is to use 3D printed molds with printed cut outs for the, to be inserted wire. Then once your powder metal permeable material installed around the printed wire you melt out the printed wire form and melt in metal. Aluminium I'm thinking. But with this you could print copper wire then spoon in the permeable. An idea I had was to combine magnetic amplifiers with motors. A magnetic amplifier uses low current DC to control high power AC current. It helps if the DC wiring is distributed inside the permeable material. So now you have low current DC controlling a far higher power AC current. The AC could be used to attract whatever magnetic material you have, making a solenoid or motor. Imagine a big U shaped magnetic amplifier of permeable material. Inside it is a bearing with a chain attached. When the mag amp turns on it attracts the chain into the mag amp big U shaped device and rolls up inside it. So as the chain is attracted it rolls up inside pulling a cable, tendon whatever. The U shape is so you have a complete low magnetic impedance path.

Grommet 10/15/2025 (Wed) 15:01:00 No.42286

I'll explain this a little different make it clearer. If you have a U shaped magnet it wants to suck up metal into the space between the U's to complete the magnetic circuit. So if you have a extruded U shape, a long walled U shaped then there's a good field in between. Now if you have a metal chain I believe it would attract it up into the magnetized U empty space. Then provide a way for the chain to roll up and now you have a linear pulling chain. The question is, as the chain is pulled up once it goes in part way will a strong attraction stop, will it continue or will it attenuate because the magnetic field has satisfied it's function of completing it's circuit????? I would think it rolling up means it continues to attract more chain as every link pulled into the empty part of the U provides a better path in the middle of the U for the field to have less resistance to the field.

Chobitsu 10/15/2025 (Wed) 16:30:03 No.42290

>>42284 How do they infuse the metals, do you know? Maybe a plasma beam?

Ribose 10/15/2025 (Wed) 17:45:32 No.42292

>>42290 It says thermal treatments so I assume they used a kiln. It is really cool that now a resin printer option exists for 3d printing metal. Much better resolution than filament and clay printers.

Chobitsu 10/15/2025 (Wed) 18:07:34 No.42295

>>42292 Yes, that is encouraging. I hope inexpensive & easy-to-use approaches as is fitting for amateurs will become commonplace for this soon. What a time to be alive!!

Kiwi 10/15/2025 (Wed) 19:05:50 No.42297

>>42267 Essentially, they started with two voice coils to manipulate the tendons of the leg. This makes some sense as moving coils is easier than moving the magnets as their lower mass means less inertia. This failed spectacularly as the current needed to move its own mass caused the coils to burn. They tried using mechanical tricks to no avail. It ends with him saying he's just going to use off the shelf solenoids because manufactured solenoids have better tolerances, leading to far better efficiency. >AFAICT from your post, your position is that we need perfect, tiny little brakes to lock all the skellington's elements into proper places (and very dynamically!) -- but at a level currently seen as infeasible to produce rn. Is that it? I presume the primary point being, is that the current drain through the coils to do so otherwise is exorbitant? That is correct, it's frustrating for me.

Robowaifu Technician 10/15/2025 (Wed) 19:41:03 No.42298

>>42295 Metal clay and metal infused filaments can also be used to make metal parts, but I am not sure how great the resolution is. https://shop.thevirtualfoundry.com/ https://cooltools.us/collections/clay

Grommet 10/15/2025 (Wed) 19:44:12 No.42299

>>42290 >How do they infuse the metals metal salts, then the metals in the salts are "precipitated" with a different chemical, salt washed out metal stays, leaving the metal, then infused again, repeat. Each time leaving more metal. Then baked to fuse. The advantage of this appears to be small feature sized parts, low cost as you are using regular resin printers and not expensive specialized powder direct metal laser sintering (DMLS). The deficit is longer times infusing these metal salts, then precipitating them out into metals with 10 of these steps in some cases. Another benefit is it appears, I think, that this makes much stronger parts as the salts are deposited as nano particles making strong parts.

Chobitsu 10/16/2025 (Thu) 02:29:36 No.42309

>>42297 Thanks kindly, Kiwi! >It ends with him saying he's just going to use off the shelf solenoids because manufactured solenoids have better tolerances, leading to far better efficiency. Makes good sense at this point in time, IMO. Hopefully we'll be able to craft high-qual windings &tc. soon-ish. >That is correct, it's frustrating for me. OK, glad I got the gist from your posting alone. Hmm. We've discussed devising some kinds of disc brake systems for skellingtons here a few times IIRC. Seems to me this would be a reasonable approach. But machining metals for it all is the primary issue IMO. I wonder if we can craft such things that would be durable enough using resin printing instead?

Chobitsu 10/16/2025 (Thu) 02:31:53 No.42310

>>42298 Thanks, Anon! >I am not sure how great the resolution is. Certainly I'd expect it to be coarser than resin printing? >>42299 I see, thanks Grommet! Hmm. Sounds like a drawn-out process, and potentially-hazardous leachate byproducts? I wonder if these issues can be resolved simply enough?

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