3D printed Robot servo for only $32 (stepper, cross roller bearing)

Check out Fantom Wallet at: store.fantomwallet.com/ and use coupon code 'SKYENTIFIC' for 10% off.
High reduction ratio robotics joint for only 32$! This is my latest stepper version of my compound planetary gearbox. It has high reduction ratio and two cross rollers bearings. I plan to design a complete robot arm with such actuators.
All 3D printable files are available for my 10 USD/month (and higher) Patrons ( / skyentific
).
Special thanks to my special Patrons: RobotDigg Shanghai, Shounak Bhattacharya and M. Aali!
Please subscribe. This will help me to develop other projects like this, to bring the bright future closer!
One time donation:
www.paypal.me/Skyentific
If you want to help this channel, please support me on Patreon:
/ skyentific
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#DIY #Actuator #Robotics

[@user-oc6fc6bf9g]

Наконец-то я нашел нормальный англоязычный канал, где у ведущего нормальное понятное произношение. "Планетари геар" - прям ласкает слух.😀 Отличный канал! Так держать!

[@freddemo]

I've experimented a lot with fully printed roller bearings, but no matter how hard I try, they always jam or backlash. I finally chose and use printed bearings using Airsoft BBs. Very cheap, and easy to make work smooth.

[@ColinJWiens]

I have BB's so I may try this with this gearbox, though I probably I won't be able to repost the design since the original is patreon exclusive.

[@Skyentific]

I am afraid that airsoft BBs are too small to make a solid bearing. Because of small diameter they may deform plastic raceway. And also here you would need to make deep grove bearing or angular contact bearing (for the trust loads (axial), which would not be easy with the small BBs.

[@Skyentific]

BTW, Let’s Print youtube channel have tested different 3D printed bearings, and Airsoft BBs one was not durable at all.

[@ColinJWiens]

@@Skyentific Great, thanks for saving me the time of attempting that

[@RinksRides]

I have tried a small 3D printed NEMA 17 7:1 cycloidal gearbox using BB's as bearings on double angular contact races. Did not work out well. Too much play in radial and axial.

[@jameshughes3014]

I feel like i'm watching the beginning of something very big, and it's exciting. keep up the great work!

[@Skyentific]

Thank you. I think this kind of actuator can be used for many applications. And this is exciting :)

[@PhG1961]

Congratulations with your new working place/studio and also with this fantastic gearbox.

[@asm2750]

I don't see your videos often but when I do I am amazed at the progress you make. Your Fusion360 skills are top notch.

[@jasoncreech4486]

Absolute beautiful design and build. That’s for bringing incredible technology to us.

[@eltripa2000]

I really loved how you explain and bring a budget proyect to us in such a nice way! 👍🏽💪🏽💪🏽 keep it that Wey

[@aytunch]

03:35 you can print all the gears in place with 0.1mm gap so you don't need to assemble them afterwards. This could be an interesting test.

[@satibel]

That might require pva between the two rings though but maybe pausing and adding kapton tape on the seam might work.

[@CatNolara]

That would add quite a bit of backlash in the gear though, and that's not what you want for robotic acuators.

[@mborowski2010]

I been following your work for the past year and I love it. I will be joining your patron this next Friday. I already have too much money in my projects this week. I look forward to building your gear boxes and learning to make/modify my own soon.

[@sticky_ricebowl]

you are an inspiration.... it may seem understandable for the experienced engineers but man watching you really makes me so confused but it also makes me want to actually learn and have fun like you do

[@swannschilling474]

Back to building!! Great one!! I am super excited to see where this is heading!!

[@jtjames79]

If I was going to make plastic bearings, I put them in a bag of sand, then strap it to a paint shaker for 5 minutes. Not all of them would survive, but the survivors would be smooth.

[@ziad_jkhan]

Interesting idea...thanks for sharing 😀

[@ColinJWiens]

I've been using drill + sandpaper

[@robertconklin3322]

Discovered your channel today, this was SO fun to watch, thank you for documenting so nicely. I'm seriously considering becoming a Patreon and printing one up for myself.

[@JPToto]

Just found your channel this afternoon and have already learned so much! Thank you!

[@eugene-d]

As usual, a very good build and explanation. I liked the gear evolution part a lot! Thanks.

[@Nerdtronic]

Hey great video. I'm glad to see you're still making videos.

[@BeefIngot]

tuning linear advance /pressure advance really helps minimize seams. you can also manually put a small slit inset at an angle around the perimeter to both be able to choose exactly where the seam is (using sharpest corner as a setting) and to spread it out to avoid a bump at a single angle

[@Skyentific]

This is a great idea!!!

[@eugene-d]

I don't randomise the seam. Instead I just file it with sandpaper or similar.

[@Skyentific]

@@eugene-d I tried this. It takes too much time to send 38 rollers per bearing, so it is 76 per joint, times 6 or 7 joints. It is too much :)))

[@eugene-d]

@@Skyentific , that's true. Then fine-tuning the slicer settings seems very reasonable.

[@laiquocbao2565]

@@Skyentific You can try using the hand drill and some 3d printed fixtures to vastly accelerate the sanding process

[@freakinccdevilleiv380]

Very nice Sky, awesome prints.

[@haenselundgretel654]

So awesome! Very well made, mate!

[@sabtvg]

Better and better every time!

[@faizalimuhammadzoda4731]

Thanks for sharing. Keep up the good work!

[@alejojhon]

Man that's just wow, soon I will be trying to do it!

[@EaSImpact]

awesome design! Thanks for the video!

[@hayfahvytsen]

Great stuff - as always!! Nice job.

[@Lionel_Walder]

Magnifique boulot de conception et d'impression !!!

[@usama.imagineers]

I love your work, thanks for inspiring 👍

[@Roboticlay]

This is AMAZING!! Thank you!!!

[@worksasintended4997]

Impressive work! Looking forward to this arm, I will probably follow you and build it :D

[@stefanguiton]

Excellent videos as always!

[@Skyentific]

Thank you!

[@iAmTheSquidThing]

I think you're doing some important work here. This isn't just a fun project, this might actually push forward consumer-level robotics significantly.

[@husamwadi2635]

Amazing work!!!

[@mrtea3122]

Another excellent demonstration of your engineering skills. One day I will become a patron and make something you have designed, I like this and if a smaller one becomes available, maybe it will be this!

[@nathanthomson7273]

Glad to see more people doing 3d printed mechanical stuff! SUBBED!

[@chestnut250]

Awesome video and cool gearing assembly! Have you thought about including o-ring glands to add o-rings to seal the unit up and keeping the gears in an oil bath? That would ensure ample lubrication as well as probably quiet the assembly down. It will create a bit of drag, but the lubrication would be more than enough.

[@jonastjepkema]

So good! This is really nice, good work :)

[@kikihobbyrepair]

Really cool design.

[@ThePretender1]

Amazing Job!!!

[@bujin5455]

Cool build!

[@sypher4912]

Great work!

[@guatagel2454]

Thank you!

[@antipastamony]

if it can stand up to wear then this will be a fantastic part around which to base your arm.

[@TheTsunamijuan]

Recently I had a similar problem with seems/print inconsistencies holding up a slighting assembly. One of the solutions I tried was valve grinding compound. Ideally Valve lapping compound would of likely been better as it has a smaller/finer abrasive size. However this solution still worked great in solving the problem. Allowing the highs of the parts to bed themselves in against each other and smooth out. (in this situation it was the relatively small layer lines, catching like threads on the part attempting to slide). This could be a solution for some of your problems as well. I've gone so far on some assemblies to intentionally over extrude, then come back with an abrasive of some form, to reach the final smoothed dimension. (works great when tapping 3d printed parts as well).

[@amandahugankiss4110]

You are so much fun! Good ideas, too.

Nice work!

[@akera9625]

Yeah man! You are the best

[@i_might_be_lying]

This latest gear box looks pretty good. Now I remember that most planetary gearboxes in cordless tools (up to some price point) is made out of plastic, which works pretty well. Maybe not as reliable as metallic ones, but still pretty good.

[@KillerJay101]

This is a super awesome idea!!!! I need to study more

[@jeisinga]

Awesome work so much fun to see this I came across you channel researching how to build a electrical actuator, busy printing the inmoov robot but I would love to print something like this also

[@mystamo]

Mr sky. Your channel is getting so big ! 100k so soon.

[@chrisdockman7237]

Very, very, cool!

[@Bianchi77]

Nice video, keep it up, thank you :)

[@TheMadRocker]

Well.. you've got a new subscriber. This was a very cool and informative video.

[@DavidG2P]

Man I am speechless watching this... AWESOME and subscribed! And I don't even have a 3D printer

[@Mr30friends]

Great job. Please keep using stepper motors. The cost difference of the motor and the driver compared to brushless is insane. And most of the benefits of brushless aren't even worth it after the power has been through high reduction ratio plastic gearing anyway. It would also be interesting to see you push this actuator to its breaking point. It might be able to handle some impressive weight. Testing different plasics would be interesting as well.

[@eugene-d]

Absolutely, I like the video to push towards high load tests!

[@satibel]

Using a cheap brushed motor with a printed plastic ring and a photointerrupter like paper printers use should make it at the same price but including an esp32/100+mhz arm board (stm32) and the driver. Using a cheap magnetic position sensor on the output might work pretty well too. Maybe using both given the price of an optointerruptor and printable transparent paper. I think making a cheap stm32 or esp32 board with an h bridge and connections for an optointerruptor and/or magnetic position sensor would be a great thing. It should be doable for

[@togowack]

@@satibel why people are bent on using brushless servo motors when TM motors and other brushed DC motors are very cheap. Are we putting a million miles on them? if economics are the problem then use the cheap stuff to demonstrate potential value of machinery. The only real cost is the servo driver and PSU.

[@satibel]

@@togowack with 12V brushed motors, you can use a free or very cheap second hand pc atx psu, they can usually handle 20A or more, so it's not even a problem, just use one per motor and run them at ~50% load, so they last and have better efficiency. windshield wiper motors are also usually fairly cheap (10-20 bucks in a junkyard, especially if you buy like 5) and have plenty of power for most applications (30 to 120W with over 10Nm of torque) also if using that with like a 1:2-1:3 pulley or even direct drive you can probably have a good enough actuator (15-45 rpm would be decent)

[@freakinccdevilleiv380]

@@togowack You guys are spot on the money, BLs are overkill for a general robotics application. I've been testing with some large brushed worm and 'box' type gear motors and they give huge power for the money. With a potentiometer or encoder you can get a reasonable accuracy. Lowering costs is key especially once a robot needs ten or twenty joints.

[@BrusnickiRoberto]

keep them coming

[@megasqrt]

good job!

[@Aleksandrov_N]

Great project! wish you luck.)

[@yorgle]

2:00 I've never seen a schematic for a gearbox before, but that makes total sense!

[@H34...]

Seeing as you're using chevron gears now you might not need the slew bearings, since chevron gears can support an axial load. One of the designs you showcased took this a step further by making the gears conical as well as double helical which further allows them to support an axial load. I think this approach would be functionally just as good as a 3d printed bearing, while being considerably simpler and using less parts.

[@madforit9661]

Brilliant

[@nigelhungerford-symes5059]

Very cool. Glad to see you printed something to hold your nuts ;) Budget project ftw

[@nickbell3546]

Could you print in ABS and do acetone smoothing as a post-process? It would be more expensive, timely, and could mess with tolerances, but would make the surfaces very smooth!

[@onurmemis3618]

What if you found some cheap Teflon bushings for the cross roller bearings? Just see what kind of sizes you can find and design the gearbox around them.

[@brad3378]

I think the problem is that the rollers have a cone shape. He mentions it at 5:42

[@onurmemis3618]

@@brad3378 You're right I must have missed that. I just don't like the idea of using 3d printed plastic for bearings. Might only work in the short term.

[@brad3378]

@@onurmemis3618 I am not at my PC right now so I can't look it up right now but look up the metal bearing used by the video featuring the 3D printed Halbach array motor. They're less than $10 each on Amazon

[@powersprouter]

This is such a great video, thank you!! Looks like herringbone gears (helical is just slanted one way, no?). Can't wait to see where this takes you. I have 3D printed some slew bearings and have been working on my gears, but my robot is still lackluster. Oh, another question, the bearing you used for the shaft - could that be 3D printed too? Too small? does it have to have a bearing?

[@youssefaly97]

Use "random layer change position" setting to get rid of the seams

[@DavePetrillo]

You could bite the bullet and just use a small plastic round stock for the rollers or make very deep groove ball bearing instead and use off the shelf plastic balls. It would still be cheap and you could clean up the seams on just the four races by hand and have a pretty smooth bearing

[@jpjay1584]

respect for the passion you put into these projects. (Genesis, most sexy actuators)

[@laiquocbao2565]

Assembly v23, lol. Great job, pls keep up these awesome videos.

[@myetis1990]

good job , now it is time to build some kind of robots using these actuators i think

[@TheTsunamijuan]

When you talked about eliminating dowel pins, but still needing something for location and alignment. I recently found a method that works great for 3d printing. Chamfer your holes, as if your going to put a screw with angled head in it. Would probably best to call this the female feature. Then on your other surface make the same feature with an extrusion and chamfer, just in the male orientation. I usually put a screw threw these features as well. It will act similar to a dowel and force the surface to align during assembly. If you want a better example send me a message I can send you some examples or possibly post a video for you to show what i am doing.

[@Ibian666]

Awesome tip. Gonna experiment with this.

[@chrisalbertson5838]

I do this but go one step more. If two surfaces meet and are fastened with screws there is no need for the surfaces to be flat. They are flat when made of metal because flat is an easy shape to machine. But with 3D plastic why not make is wavy or dimpled like a golf ball. I use truncated pyramids with long rectangular bases between the screws. Or if the surfaces are round like pipe flanges the bases are made of concentric arcs. I use about 1/4 of the surface area with these. You might call this "intermittent tongue and groove." The idea is that 100% of the shear force is taken by the interlocking geometry and the screws only see tension force In Fusion360, I fist draw the base, extrude up with 15 degree taper ange. Then use this as a tool to subtract from the mating flange. Finally, I fillet ONLY the make features. It is self-aligning but, better is is 4x stronger in shear

[@vannoo67]

Inspirational

[@ozr2222]

finally i got the name of your grease! :D

[@felixhubner8539]

Maybe you can use POM/Delrin rod as rollers, it is really cheap, has a smooth surface and is ideal for this application.

[@jekker1000]

a really dedicated design. since you have so much space in the center left, wouldn't it be an option to construct an axis there that holds the hull? preferably mounted with x-bearings or o-bearings (depending on loading case). You'd need to have a machined axis, maybe it could be printed because it will be stationary but even when machined it is probably around 30-50$ and you gain a lot of robustness and save the big plastic bearings

[@DownToEngineer]

Very well designed, are there STL files available? Would love to replicate

[@rafaslusarczyk4030]

Cold you say more about your 3D printer and parameters to print ? Great work - waiting for next steps! best regards

[@JM_Tushe]

It's so amazing, it makes look mine a middle school project. ;-;

[@rtimech81]

Hello, your videos are very beneficial thank you so much, I wonder that these parts are very smooth and precise. which 3D printer and material are you using?

[@Vernon1xx]

You are amazing!!!!!

[@richardwatkins6725]

awesome

[@viniciusnoyoutube]

Nice

[@richardathey3116]

Awesome vid, what 3D printer do you use ? The quality of the prints are good

[@davidmay2328]

Hi, I amazed with your design and I tot inspired by it.I have a little question. What is the small part you use in the pinion

[@zivfriedman2312]

can you measure the torque that the new gearbox produces?

[@jasonborn1612]

Nice Job! Do you have plan to make a backdrivable version?

[@kirilchi]

Do you have a link to the video of servo with brushless motor? Looks very cool!

[@remsonic]

Прекрасно!

[@Skyentific]

Спасибо!

[@rdyer8764]

Well done! Why didn't you use sandpaper to smooth the imperfections (printing seams) in your prints?

[@evanemanuel1774]

because of cost vs benefit. Yes, sandpaper can remove a bump, but it also will remove material around the bump. By the time the bump is gone, you've done more damage around it. There are ways to remove a bump on an arc while touching less and less of the surrounding material, but the more accurate you get, the more you approach methods of machining and lathing. 3D printed components are supposed to exist in lieu of machining. So in this case, just skip the sandpaper or other post-print processing, and just figure out a better way to 3D print to avoid the problem. In the domain of 3D printed parts, imperfect parts are trash. "Print better" is the fix, not post-processing.

[@erhardpostinger1326]

13:39 - agree

[@myperspective5091]

👍🙂👍 Did you also consider curved hourglass shaped bearings or barbell bearings?

[@TheNamelessOne12357]

Use Linear Advance to remove blob on the seam. And make Strain Wave Gear next time. :)

[@ico-theredstonesurgeon4380]

Very cool! Where do you buy the bearings?

[@jeyanthgoringe600]

I mean, you could always add a second stepper motor connected to the same driver to double the power.

[@Skyentific]

This is a good idea! For most application one will be enough, but fir extra power, this is a great idea!

[@polkiipo]

Nice work ! What is the name of the part you added at 12:30 please ? It would be very handy for my projects ! Nice discover !

[@mechadense]

Instead of cross roller bearings I'd go for *conical gear bearings*. - This sould: ★ be much more silent ★ remove the risk of the rollers starting to slide (due to getting caught in those insufficieltly randomized seams), which may lead to a rapid self-destructive internal meltdown.

[@buidelrat132]

How might you add closed-loop control to this arrangement?

[@TheLordbruh]

Hello @skyentific, what about the resistance? did you analyse if the gears break as PLA material is fragile?

[@DPTech_workroom]

Need a version with stepper motor and encoder for closed loop ))

[@SilverRainSR]

Вот так встреча))

[@DPTech_workroom]

@@SilverRainSR А чего удивительного? )) Всё же технари )) Ну и себе хочу собрать подобное "AR3 6 Axis Robot"

[@DPTech_workroom]

@@SilverRainSR kzbin.info/www/bejne/mZetn2qKaalgbM0

[@SilverRainSR]

@@DPTech_workroom да тоже слюни пускаю в эту сторону, но кроме как поиграться применения нету

[@Skyentific]

А кто сказал что «поиграться» - это не достойная цель?! :)))

[@luke2642]

Once you dial in the seams and clearance on your printer, print in place would remove most of the assembly steps!

[@estebanpa7923]

Exelent