The cheapest 3D printed actuator for robots (with brushless motor)

[@ivan2vp61]

Why do you give like to the video if you don't watch it still? Me: Because I know that the video it's incredible. Regards Skyentific

[@KhalilEstell]

I cannot wait to see a durability test of these plastic gears in action. As well as a max torque and destructive testing of the gearbox as well.

[@ericlotze7724]

A "FDM 3D Printed Part -> Metal Cast (optional -> heat treatment) -> Filing for dimensional accuracy" workflow would make it even more durable!

[@ericlotze7724]

Also some crazy filaments like Nylon, PC, (And composite variants), etc

[@roryevans5032]

@@ericlotze7724 Metal casting is dimensionally challenging, and leaves a poor surface finish for gears. The slight give in plastic makes them work much more easily.

[@ericlotze7724]

@@roryevans5032 Ah ok, well thanks for the insight, the metal idea is just an armchair one of mine. Would vibratory sanding help the finish or not even something like that?

[@roryevans5032]

@@ericlotze7724 to work properly metal gears need a smooth surface as they roll against one another. If the metal is rough they scrape and seize up, the only way to avoid that is make the tolerance lower, so there is more clearance, but that causes backlash. For the same reason you lose a lot of power to friction, and make lots of noise. Most gears are machined or ground, which gives a better surface quality than casting. Post processing is also difficult as you have to factor in the wear from the polishing step, so again to work you will generally have to lower tolerance and get backlash, noise, and low efficiency.

[@dobrincuemanuel]

can't wait to see load and backlash test, great work

[@eelcohoogendoorn8044]

Backlash looks to be very low. I suppose thats one of the advantages of plastic; you can size everything to be under a tiny bit of pretension. For as long as the wear doesnt accumulate that is, I suppose. But printed in nylon these should last quite a while.

[@justtestingonce]

Backlash is overrated!

[@Build_the_Future]

Videos like this, are why I'm a Patron.

[@Skyentific]

Thank you for been long time Patron!

[@johnyoungquist6540]

Elegant design and use of 3D printing. Lots of print time. I routinely embed hex nuts in printed parts to make them captive and invisible. Just print a hex pocket, stop the print at the right time, put in the nut and print over it. The trapped nut can even take a load in both directions. I’d like to see how this performs with a lot of use. Nice job.

[@davoriffic]

beautifully engineered, I love how quiet it is when it is running too.

[@FilterYT]

I like how you've split the planets on the herringbone to solve the assembly "problem" where GearDownForWhat has split sun rings. Also, I like the simple coupling to the motor.

[@GearDownForWhat]

Nice work man! I like how you did the planets. That removed the need to split the rings for assembly.

[@Skyentific]

Thank you for watching my channel and for the inspiration!

[@dekutree64]

You're alive! I was starting to worry that you'd given up youtube. Excellent design. Very slim with the motor inside, and clever use of the rotor spokes like keyway shaft. I haven't seen that done before. Too bad the $20 5010 motors don't have anything protruding to use, since they also have the shaft bottom screw. Gartt 4108 has protruding spokes, but would need a different approach for magnet mounting.

[@konserv]

This gearbox even can be the part of arm, that's amazing!

[@plotze0692]

The most important part to my robotics education is your channel :D

[@marco_gallone]

Fascinating concept with the constant planets/planet carrier and adapting the sun:ring ratios. Unconventional but effective!

[@sambailey8378]

Wow you read my mind! I made pretty much the exact same thing a month or so ago. Although alot smaller and lower gear ratio! Makes it much more backdrivable. Good video! Nice work!

[@testservergameplay]

Love this design! It's so quiet, yet affordable.

[@DMonZ1988]

yay, i was just hoping we would hear from you again soon! fantastic work, the cost considerations of this design are definitely a huge benefit but it also seems to work very well! of course it will wear eventually but that is the same for any 3d printed solution, and the beauty is that they can be replaced and replicated cheaply and easily when needed. and given the cost savings, one can spend a little more on a broad range of more expensive printable materials that i think can last a very decent time. great to see you! looking forward to the testing video! :-)

[@eelcohoogendoorn8044]

If printed from nylon, and given that such a diy robot arm transmission hardly makes the number of cycles as that of a city bus, I think wear is probably not a concern at all. Even PLA has been known to last for years in all kinds of gearing applications.

[@c0ffeefell0w76]

Great to see a video from you again! Interessting as always.

[@NistenTahiraj]

I tihink you've hit a homerun with this new design. The durability would probably improve with nylon printed gears. I'm interested to try this out with very hard resin like Siriya Tech Blue

[@crashfactory]

this looks fantastic! good job on the design! very well thought out mechanism, playing to the strengths of 3dp and leaning away from it's weaknesses.

[@martylawson1638]

Output torque tries to tumble the planets. This is probably a large source of friction. GearDownForWhat used three or more gear layers to balance out this force, but a planet carrier and bearings could do the same. larger pressure angle gears are more efficient under radial loads. (i.e. 35 or even 45 degree pressure angle) Finally, I expect that heat will be the weakest part of this gearbox so running it immersed in soapy water, or using higher temperature materials will help a lot. (heat is why Nylon, Delrin, and Torlon are the plastics of choice for gears)

[@eelcohoogendoorn8044]

I agree, the triple-layer structure of his strongest gearbox is probably quite important; he has some tests also showing this has a big impact on torque-efficiency. For pancake formfactor like this I suppose its not so important, but if scaled lengthwise, the torsional and flexural rigidity of the planets will also be crucial to torsion efficiency and backdrivability I think. GearDownForWhat pressed in steel rods; that solves the bending; but itd be better if they were epoxied in I think, so torsion can be transmissed efficiently along the length of the planet, rather than bothering your layer lines with it. Flex in torsion will cause stress to be concentrated on the teeth where the rings meet.

[@jorginhoapmyou]

very good! i wish to see collaboration with you and james bruton!

[@Skyentific]

I wish too! :)

[@DMonZ1988]

@@Skyentific i have mentioned you to him quite a few times. you are my two favourite channels. if he is too busy or successful to organise a collaboration with you, maybe you could do your own version of one of his projects, and treat it like a design challenge. then when both are done, you can make your robots compete. or, maybe you can design something useful to add to one of his robot platforms, which are all open source. i'm certain he could not say no to collaborating or at least featuring your work then. it would be very cool to see, you both make incredible things!

[@MarkusOsmers]

@@Skyentific Just buiid his really useful robot design with your creation of an 5 or 6 axis arm. And someone needs to tell James to rebuild the Base with a rectangular base and with Omni-Wheels.

[@lidders]

He’s just developed a back-drivable cycloidal gearbox.

[@konserv]

That's awesome! You're a real inventor. Thanks for sharing. Hope, my grandkids will visit your monument in 100 years 😁.

[@Skyentific]

:))))

[@DiegoHurtadoPimentel]

That monument will be 3D printed

[@tcratius1748]

Impressive I have seen one of the other KZbin who made a way to test the torque on the gear, yet it is a fantastic design 👍

[@ProductionsExoTic]

When I wrote my bachelors thesis in mechatronics, I tried to develop a 3D-printable gearbox that; had high reduction, could handle high torque, was back-drivable and had high precision. To that end, I 'invented'(didn't know of any other at the time, though it turns out there were some similar ones) pretty much exactly this gearbox. In my attempts, I managed to make back-drivable gearboxes with up to 1:100 reduction that could handle a few Nm of torque. I reckon I could go way higher too, though I was very limited due to the pandemic. You mentioned that you wanted them to be back-drivable, I might have some tips if you're interested. It seems you have access to very high quality 3D-printing(at least better than what I did), so it would be really cool to see you try out some of my ideas/designs. Also, on a completely different note: I am currently taking a masters degree in cybernetics and robotics and would LOVE to see much more content on your control systems! Would be really interesting!

[@albertogregory9678]

You may want to look into the lubricant if you have not already, superlube ptfe or chapstick work well

[@wiener35]

Wonderful work. I watched with pleasure.

[@Skyentific]

Thank you!

[@DarrenC_1024]

There are eyes on the planet gears, it cannot be unseen!!!

[@PaulGouldRobotics]

This is an awesome design. Are you planning on making a larger one with your 9235 motor? Cycloidal gearboxes use a lot of bearings, I've been testing large 3D printed bearings with moderate success.

[@alexaizenberg8078]

Write comments to push video to recommendations section!

[@Skyentific]

Thank you!

[@PhG1961]

Awesome video and great ingenuity !

[@aaedmusa]

Amazing! Very well done.

[@dhruvbose8294]

Genius! No other words.

[@Build_the_Future]

I would love to see a back-drivable version. I not sure but I think the most you can do to have a back-drivable gearbox, that is not too much static friction is less then 10 to1

[@Skyentific]

Completely agree!

[@dekutree64]

Here you go kzbin.info/www/bejne/lYfKiYKYmMuLq8k The carrier-driven variant has one less stage of tooth engagement, and thus higher efficiency (=more easily backdriveable). But it requires lots of bearings, and has higher planet RPM which may or may not be an issue depending on how fast you want to run it. Also you probably have to accept a little higher backlash to get backdriveability. Although there's one trick I read about in the comments on James Bruton's cycloid video that I really want to try, which is to use a dual-head printer to make gears where just the outer one or two walls are flex filament, and the rest is hard. The compliant surface allows tighter engagement without jamming, eliminating backlash. But it may still add enough friction to prevent backdriving. Would be great for robot arms though.

[@Will_Huff]

Would like to have seen a faster input speed to see how quick you could get the output shaft to move. Great video as always!

[@Nerdtronic]

I second that. I'm always interested in how fast the actuator can move from one position to another

[@dekutree64]

@@Nerdtronic By the look of it, high speed will probably heat up pretty quickly, but should be ok intermittently. Great for robot arms. If you want continuous high speed, print with a little more clearance.

[@ml1186]

Thank you, this was really interesting stuff! I was expecting it to be very noisy but was fairly dampened compared to what I was imagining. Also from the video it sounds like the grease dampened some of the rattling noise a fair bit.

[@MaxMustermann-sm4qu]

Great Design !!! 👍😃 Cannot wait to see your praktibilety testing and using it in one of my own projects. 🤩 Thank you a lot. 💐

[@MrHaggyy]

Nice video, also really good packaging for a robot joint.

[@TheJacklwilliams]

Great presentation as usual. My first thought was printing this out of carbon fiber / nylon should provide a pretty durable planetary gear configuration. I haven't joined anyones Patron yet as well, the coffers aren't very full as of yet however I'll say this. With my studies and what I'm working on (IT Guy looking to switch to robotics) I'm thinking I'll be joinning yours for certain. Amazing channel, and you sir have certainly shown your knowledge to at a professional level. I want to print the planetary gearbox. Anyway, as always, THANK YOU!

[@brenno3735]

This is SO cool!! Keep up the good work.

[@aaedmusa]

Consider using regular spur gears to make it backdrivable. Great video btw!

[@sato4kaiba]

I would not say its unfortunate that this system is not back drivable. This is why, if I am using this system to drive a shoulder axis on a robot, I would not want the weight of the elbow or the end-effector to drive the arm and strain the motor. That way when I put the shoulder into a position, it will stay. This will save energy as I will not have to use too much holding torque. Its true that the system will be limited to how much torque it can handle in the back drivable state, it means that the feedback control will help. I watch a video on the FANUC palletizer and it was this way. The system was designed to take more than 600lb one the output system where even the weight of a 250lbs man could not back drive the system joint. Nice work. Will like to this this system you designed. 😁👍👍👍👍👍

[@tatatatmax]

Nicely done -- similar to the Genesis Robotics gearbox!

[@serialdad33]

I just thought the same.

[@Skythedragon]

Nice As for the backdrivability, I've seen something about bilateral drives, which also use a compound planetary setup, but they are backdrivable, somehow

[@OlleMattsson]

So nice! Very inspiring to see!! Thank you, sir!

[@TheLordbruh]

congratulations @skyentific!!!, what is the backlash of it? why didin't you use a bigger teeth size and increased the number of teeths causing a reduction actuator size? maybe nylon screws could be a better solution to the increase the durability of material.

[@qamarkilani551]

Very nice video .. please keep up the great stuff your are doing

[@sabtvg]

Yes please show us more tests on 3d printed actuators and show us which printer I should buy jiji. Everything change if I can print it.

[@Skyentific]

I use prusa printers.

[@morkovija]

This is great! Finally might have somewhat cheap 3 axis robo arms!

[@zabihtoosky658]

Great work, Thanks for posting you are a genius

[@R2D2Belgium]

Great design looking forward to see the torque test

[@antonwinter630]

looking forward to seeing how much load it can take

[@Shreyam_io]

controller board has really made the difference in terms of cmpactness

[@swannschilling474]

I made a 3d printed Cyclodial gearbox and am still preferring it over planetary gearboxes, the low backlash and high torque comes at the price of those bearings and also those bearings add weight...but I guess it is still the best option for a high torque, low backlash and backdrivable robotic application! But I am very tempted to give your design a try, nice and smooth and looks like there is very little backlash!! 😎

[@alfredoj1349]

You are a master sir. Just inspired me to build more stuff….

[@Snookers_]

This design is incredibly similar to a design patented in the US as a "gear bearing drive" (US8016893B2). Really the only difference is the use of helical gears as opposed to rings to hold everything together.

[@MarceloRodrigues-yx3ty]

Awesome video as always! I would suggest to print using Nylon instead of PLA. Much more durable, strong and resistant to abrasion. Thank you!

[@ArnaudMEURET]

The whole point of the design is to be printable by Joe Lambda. Nylon is not trivial to 3D print.

[@MarceloRodrigues-yx3ty]

@@ArnaudMEURET Nylon tends to warp and require higher temperatures, but isn't that hard, specially for round parts. But I got your point.

[@guillaumerouault9083]

Really nice design. ;)

[@sabtvg]

Thank you very much

[@dinoscheidt]

Love this channel

[@Физик-г4о]

Спасибо, что по русски тоже понятно! Когда-нибудь соберу 3d принтер и разберусь с CAN шиной и сделаю робот арм для работы на конвейре.

[@odinata]

1. What motor is this? 2. Where do I get the electronics, how much is the cost? 3. What is the magnet for, and how does it work?

[@jacobbranker159]

Beautiful work

[@stefanguiton]

Amazing!

[@qck57594]

Interesting devices,thank you.

[@Scott_C]

Whooot! good project!

[@thiagoennes]

Have you taken a look at "hoverboard" bldcs? It seems they have a whole lot of torque for not much money!

[@SpaceManAus]

Nice print job, now to build the robot.

[@brendansimons6811]

Maybe one of the reasons it won't backdrive is that the planets are each trying to twist out of plane under load. I have a theory that the whole thing will turn more smoothly (have more even loading on the gear teeth) if the planets were supported on a carrier with bearings. You wouldn't need the output sun gear in that case.

[@matsv201]

Hmm.. I´m not sure about this, but it seams to me that the rotational force of the motor ring gear would be considerably lower than the output ring gear, still they are equally thick. The thickness of the gear should be pretty much linearly related to the maximum torque. So if the torque of the motor gear is say 5 time lower than that of the output gear, it should be able to make it 5 times thinner. That should also reduce rotational friction, and possibly make it back drivable. It of cause would make it quite a bit smaler and a bit cheaper as well

[@jcugnoni]

Great design!! For info Igus sells 3d printing filaments with their special polymers (friction optimized and also some high strength fiber reinforced ones). Also they have a 3d printing service. Maybe you could setup a collab with them ? I would be interested to know if their 3d filaments bring some additionnal benefits over regular PLA.

[@ciarfah]

What was the reason for orienting the planet bolts as you did?

[@Skyentific]

The 3D printer does not 3D print perfectly. There are always some micro imperfection. With my orientation all this micro imperfection distributed evenly. This makes everything rotate smoothly.

[@ciarfah]

@@Skyentific Ah yes, clever. Makes sense since you have such low play in the gear mesh, to prevent binding. Did you try installing the planets in a random orientation before orient them this particular way, or was it just your intuition?

[@clickle23]

hello are the two sun gears rotate in the same direction and same speed? I am trying to understand for the 2nd planetary, it seems to have input speed from the carrier and output at the ring, and it looks like an overdrive?

[@luoyangbobiprecisionbearin986]

Thanks for sharing!

[@Jkauppa]

you can use it as a floating 1:1 (not back drivable forward) and 30:1 (normal backward) gearbox

[@Jkauppa]

it can be designed to use the non-back drivability stopper

[@Jkauppa]

it will stop and not move if not self ran to move, like a car on a slope, no brake needed

[@Jkauppa]

it has the same property as a screw actuator, it will not move if not specially self-moved

[@theodoremiller7430]

That was very good to me I leaned something new

[@Direkin]

Very cool!

[@jiimz]

Very nice. Very very nice. Have you considered winding your own motors yet?

[@TheNamelessOne12357]

Wouldn't it be better to design the ring gear like a clamp or make it out of two parts? Like this you can put everything inside and assemble/tighten it. The backlash would be also adjustable. Hope you will do stress and wear test on this gearbox soon. I guess, this motor won't be able to break the gearbox, but how much torque will it give? Really interesting.

[@fisch747]

Try a lower gear reduction maybe then its backdrivable? Normally reduction of 7-13 is used for walking robots where backdriving really is needed

[@carlschmitz7909]

great video !

[@MaxWattage]

I have some questions: 1) Which of the three gearbox types (Harmonic, Cycloidal, and Planetary) are used in modern commercial robot arms? 2) Which of those three gearbox types has the lowest backlash? (low backlash being a requirement for precise and repeatable robot-arm end-effector positioning) Thank you.

[@Skyentific]

1. Harmonic 2. Harmonic But: do you want to stay in the past with slow robots, or go into the future with fast robots? If the future is your choice, you should use planetary :)

[@TheBowersj]

maybe better with a generator for wind turbine, or something that need 13:1 reduction in speed. Its almost like a stepper motor, good accuracy as well with very little noise or vibration included.

[@hTfvmGNrIZ]

genesys robotics has a gearbox that looks just like this one. they have some crazy actuators and axial drivers.

[@de-bodgery]

Your planetary gear box has lots of internal friction. If this was cleaned up and smoother moving it would be back drivable. There is no reason for planets to NOT be back drivable other than frictional losses jamming it up. I think with use and the gears wearing off the 3D printed ridges on them, that it will get smoother and maybe it won't jam up anymore. Nice gear box and seems like it should be very solid and durable.

[@ssa7843]

Why did you remove the magnetic screw and put in a non magnetic one instead? I just missed a bit the explanation why you did certain things, but found in the comments also the reason for the special screw alignment

[@Skyentific]

Magnetic screw would decrease the range of the magnetic field from the magnet for encoder. Most probably it would work with magnetic screw too. But with non-magnetic screw the magnetic field should be a little more intense.

[@sripruthiwi3435]

good work

[@BeefIngot]

The only problem I foresee with design is that the encoder is at the motor not at the other end which means you lose the absolute nature of the measurement of the encoder. I suppose that can be resolved with limit switches, but means you cant simply turn it on and know where it is.

[@davidbarrett7424]

Superb package, loving the printable / afforable /accessible and compatct aspects of your design. I'm thinking back drivablilty is important and 28:1 is too high for that, is it possible to make a 10 or 15:1 ratio? Would a carrier for the plants help keep gears "aligned" and lower friction help back drivability? looking forward to some more Scientific tests of strength, backlash, durability etc. Cheers

[@willyouwright]

Do a video on several methods for robots to sense. Led, radar, load sensor, back emf ect

[@gistnoesis9116]

Nice. Is it PLA ? How hot does the motor get ? Seems you can add air flow for cheap too. Because it's not backdriveable, you can use zero current for holding so the motor shouldn't get hot, and when you spin it, adding a small propeller to the motor should help cool it down.

[@willyouwright]

Controllers are cool. Actuators are cool but logic and sensing is even cooler... for example following robots

[@florianarmange6769]

Amazing ! Can you tell me which CAN to USB your are using in this video ?

[@kaleygoode1681]

Could eliminate the screws using herringbone gearing and print the whole lot as a single print!

[@Skyentific]

Yes, but in this case it is difficult (almost impossible) to have very tight tolerances.

[@justinstorm]

Love your channel, learn so much from the videos. I am trying to build a robot arm similar to the one from innfos. Any advice on what to keep in mind?

[@radug9594]

First lol I'm working currently on a tiny cycloidal drive for gimbal brushless motors, any tips?

[@klausnielsen1537]

Love it. Well done! 🤭

[@shodanxx]

Nice work, have you considered 3d printed sintered gears ? (You only need to print the teeth in metal, like a hollow shell, and then fill with epoxy for structure.

[@shodanxx]

Also you can print stators and wind it yourself then insert magnets in the ring gear. Only motor's bearing cannot be printed

[@tadasskeltys]

Leaving a cookie for the algorythm :)

[@earielflare2203]

Приятно видеть человека, занимающегося любимым делом) Вопрос автору - вы не хотели бы замутить общий проект с Сергеем Дорошем? Он занимается волновыми редукторами и актуаторами.

[@grappler185]

I'm brand new to robotics. I'm enjoying your videos. I'm hoping to build a small table top 6 axis arm with at least a 2 kg payload for deburring parts that come off my CNC mill. I really like this mechanism. What would it need to be back-drivable?

[@bschena]

If you are just controlling position then backdriveability doesn't matter. However, if you want to do high quality, open-loop force control (by say controlling motor current) then you will be in trouble. Backdriveability, often referred to as "drive transparency" by roboticist is the Holy Gear for a well controlled, force feedback robot arm. Say, for example, you need to control contact force for, say, a deburring operation, then transparency/backdriveability will likely be required - unless you have a lot of compliance (springiness) between the robot arm and deburring device.

[@begeekru]

Nice gearbox, what is theoretical maximum rotation speed and torque?

[@dansam1395]

very cool design, Perhaps you can post the project on your website for purchase?