My 3D Printed Harmonic Drive is Surprisingly Powerful!

This is my 3D printed harmonic drive (strain wave gearbox). It's easily capable of 10NM torque output and has surprisingly little backlash and deflection even under extreme loads. It may not be metal, but the performance is surprising! It's low profile, durable, and can be used in a few different configurations. And best of all, it's super cheap! The gearbox itself is less than $20, and then just add the price of a stepper to drive it!
If you would like to find out more about this gearbox or get the parts to build your own, the project is fully open sourced and can be found here:
github.com/DDeGonge/OS-ARM/tr...
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#3dprintedlife #gearbox #harmonicdrive

[@cavemaneca]

This is actually the most impressive 3D printed strain wave drive I've seen on KZbin. Hopefully the video gets the recognition it deserves.

[@3DprintedLife]

Thanks I really appreciate that! :)

[@Blox117]

cool but pretty useless functionally when you could just use a direct drive motor

[@Blox117]

and no, they aren't "100 dollars"

[@networkedperson]

@@3DprintedLife you are promoting a company whose cloud logistics division directly supports ICE kidnapping brown children, among other human rights abuses.

[@sonicsupersam7793]

@@Blox117um what?

[@StuffMadeHere]

I knew I recognized that voice. Hah. Sweet design dude. Using the belt is very clever.

[@3DprintedLife]

Thanks Shane, hope you've been doing well and congrats on your insane success! If you ever find yourself with one too many CNCs just let me know 😁

[@Whynot83848]

@@3DprintedLife😂

[@mr_voron]

For interfacing shafts with 3D printed parts in a VORON, we use 20T pulleys with the top flange popped off, and with screws driven in to fully stabilize it. It gives you a solid and cheap interface between a steel shaft and a printed part.

[@3DprintedLife]

On yeah I built a voron extruder a while back and remember that feature. I'm not sure I have room but I'll definitely play around with this and see if I can make it work. Thanks for the tip!

[@mr_voron]

@@3DprintedLife if you’re tight on space, use the 16T gear. They are much smaller, but still provide better interface than the nut + set screw approach.

[@3DprintedLife]

@@mr_voron yeah true, great suggestion I'm definitely going to try and make that work, thanks!

[@Justkyrios]

This is what I was thinking immediately after seeing the screw/nut combo break!

[@gedr7664]

do you have a link to this? I can't picture it in my head

[@CNCKitchen]

Great work! Makes me want to work on gears and gearboxes again. Any idea on the efficiency of such a design?

[@3DprintedLife]

Thank you! Yeah gearboxes are a lot of fun. The efficiency is definitely not great, maybe 60% or so right now. I intentionally went for a very tight tolerance between the flex spline and housing teeth to keep backlash and deflection to a minimum. I'll be doing a lot more testing with this gearbox once I get my control board made and start building the arm, so I can throw in some efficiency tests too! Perhaps even comparing performance and efficiency of different materials used for the flex spline.

[@jessemenezes3274]

@@3DprintedLife I'd love to see a video(s) with the mechanism printed out of different filament and tests of efficiency and longevity. Would be cool to see the arm casing printed out of Carbon Fiber PLA. Thanks for the awesome content!!

[@Side85Winder]

yeah use a planetary gear box instead, actually you can buy a nema 17 with a planetary gear box with more torque than this off the shelf it has a 20:1 ratio, It might cost a little more but its metal and wont brake. if you had one on a nema 23 well you would have close to 2x the torque of what this one you made or you could have similar toruqe with a 10:1 ratio.

[@whyme6742]

@@3DprintedLife You can replace the flexible spline with a planetary gear and reduce the output teeth by the number of planet gears.

[@ClickItYT]

@@Side85Winder But what about the backlash? That's the most important thing on a robot arm.

[@redshepard5306]

Cool project, great video quality, and most importantly, you were clear and concise about your thought process, you really brought us along for the build. You got my sub fam. Keep this up

[@Venom.427]

Satisfying the design manufacture and testing !! keep up the good work.

[@nrdesign1991]

This shows a great amount of dedication!

[@erikziak1249]

Brilliant design! Also, I really like that you do everything by yourself. I believe the experience you gain and all those things you learn when doing this is super valuable and the best thing is that noone can take it from you. I also applaud that you share with the rest of the world here. A true passionate inventor/tinkerer, enjoying the process.

[@3DprintedLife]

I learned a while back that I'm gonna end up spending more and taking longer by doing everything myself, but the experience and knowledge gained more than makes up for it. Usually. Sometimes I go too far down the rabbit hole and never finish projects

[@erikziak1249]

@@3DprintedLife I know. Have been down that rabbit hole way too many times.

[@vishal01mehra]

So glad to find your channel. Love your work. Keep up!

[@longboarderebright]

excited to see the full robot arm in action! i always wanted one of those automotive car building robo arms!

[@3DprintedLife]

I am too! :D

[@nickcox2481]

I JUST watched Tenet last night! Your intro was awesome!

[@3DprintedLife]

Thanks glad you liked it! I was definitely inspired by Tenet for that one

[@robgoodsight6216]

🤣🤣🤣❤👍...watched already twice! And thought exactly the same!

[@THESLlCK]

@@3DprintedLife that movie was fantastic

[@londonnight937]

Outstanding performance from your harmonic drive design! I would be proud of it!

[@3DprintedLife]

Thank you!

[@AllAmericanBeaner68]

Never even heard of strain wave motors until this video, great stuff and just subscribed!

[@sabtvg]

Incredible! Congratulations! And thank you!

[@michaelrechtin]

This is very well done! The testing with the load cell is genius.

[@3DprintedLife]

Thank you! Btw I've been following you for a few months now, really enjoying your content and can't wait for more! You deserve way more subs!

[@OfficialJervin]

@@3DprintedLife mentioning that you subbed to this seemly random cool guy earned you AND him a new sub

[@matijavinazza9861]

I'm making a robot arm for a school project and will probably also go with the steppers. This might come very useful. Thank you for making it open source.

[@jupiter909]

Fantastic video, all the best for your projects; Keep up the great work!

[@3DprintedLife]

Thank you!

[@impuls60]

You should design in stabilizing rollers at 90 degrees to the main bearings. That would function as a limiter for oscillations at high rpm.

[@3DprintedLife]

Ahh good tip, I was wondering why some other designs had those bearings. thanks!

[@rolandorodarte893]

Awesome video once again! I can’t wait to see the next one!

[@3DprintedLife]

Thank you random internet person!

[@gordon6029]

Looking forward to this build

[@raymonroe1983]

That's pretty epic 😍. Didn't even know that existed until now.

[@Bastanien]

In my experience Taulman Bridge is an absolute nightmare to print with, you need very high temperature enclosure to prevent warping. I switched to Polymaker CoPA and PA6-CF, both of which prints almost as easy as PLA, sticks perfectly to glue stick, doesn't warp, etc. As long as you keep the filament dry and your printer hotend can handle the temperature.

[@gerarddantel5931]

I enjoyed this video more than I planned on. Kudos for the cinematography. I enjoyed it all. You actually finally gave me an excuse to start working on a robot arm. Although I had been trying to stay away from the trials and tribulations that is a 3D printer, I'm at least thinking about it now. I love the narration, the troubleshooting, the production. I'm so impressed with all your skills. Keep it up.

[@3DprintedLife]

Thanks so much I really appreciate it, glad you enjoyed! :)

[@Grinstopher]

random reminder that CNC mills also exist

[@willfiguex1]

Good job! You have good production and good content, the work will payout. Keep it up!

[@3DprintedLife]

Thanks, will do!

[@JasonLooseArrowAlso]

Thank you for this video. I appreciate seeing how it takes time and many iterations to develop something. It helps me to see this because you know a lot more than me and are way smarter than me and, while my projects are far simpler, I have to keep revising my designs over and over. They just keep coming out not-quite-right. Or, just wrong. I keep thinking smarter people just make things perfect right away and I'm doomed to fail because I keep making mistakes. It's good to see that nobody is perfect, but you keep doing awesome things and making awesome progress. Thank you again!

[@3DprintedLife]

No one is perfect, even though I try! Just wait until my next video, there is going to be a lot of pain and a lot of failure in it :D

[@JasonLooseArrowAlso]

@@3DprintedLife I'm going to be in it??? LOL **weeping**

[@simonmerrett]

Great video. Still appreciate seeing the progression, rather than skipping to the finished version. I'm sure by the time you have printed 6 you will have refined the design much more and need to reprint the first one! Don't forget that while the single design is attractive from a scalability perspective, your robot arm will thank you for making lighter gears near the effector and beefier ones near the shoulder. And with your parts being printed tooling = free so CAD time is your only real excuse not to have a couple or few sizes.

[@3DprintedLife]

Yeah all good points! I'm only planning on using this gearbox on the two main hinge joints for exactly that reason. I'm still figuring out how I'll handle wrist motion and the rotary platform, but I expect I'll go with a simpler reduction technique like just using belts.

[@MrDj200]

Very good video. I'm looking forward to seeing updates on the arm :)

[@3DprintedLife]

Thanks!

[@costaliberta5969]

worthy of a subscription! hope you finish it, eventually! ty

[@3DprintedLife]

Thank you, and welcome!

[@solutionhacker]

Subbed! Your design, demo, and open source mindset is amazing!

[@3DprintedLife]

Thanks I appreciate that!

[@totallyrandomlocksandpicks1213]

Awesome video and thorougher explanation of the thoughts behind design process.

[@3DprintedLife]

Glad you liked it!

[@jsquirre]

I've printed with bridge.. make sure to put it and a heated dryer for ideal printing. I put the heating unit of a food dehydrator in a box with my filament overnight. I would use a more aggressive tooth pattern as well. The bridge nylon can either smooth the surface enough to become a bushing or with the friction weld moving parts into stationary parts.

[@NathanBuildsRobots]

If you're doing a lot of structural prints I'd recommend upgrading to a direct drive extruder. Even after calibrating my ESTEPS my bowden setups always have a tiny amount of underextrusion at the start of a tool path. This introduces a bunch of weak spots for a failures to occur, which will be even more significant under cyclic loading due to the way fatigue cracks form. I like the animated CAD visuals keep up the good work!

[@3DprintedLife]

Yeah, good point. I've spent a lot of time tuning to correct for this, but going direct drive would make everything a lot easier and stronger. Maybe one day :) And thank you!

[@R3d_8]

For anyone else with the same problem, esteps won't fix it, but linear advance will. You can also reduce speed and acceleration.

[@deplorablesecuritydevices]

Exactly what I needed thank you!

[@willozfam]

Good job! Enjoyed your tongue-in-cheek style. Fits your fellow engineers very well. 😉

[@you2709]

epic part my guy, about time someone solved the flex spline issues. Im definitely printing this- after i struggle with solidworks long enough to get the inventor files working :)

[@3DprintedLife]

Awesome, and oh no haha. I'll upload an assembly step file tonight!

[@you2709]

@@3DprintedLife Awesome, thanks a bunch.

[@kpatrickm]

Haven't the slightest clue about any of that BUT really well made and explained video. New subscriber UnLocked.

[@3DprintedLife]

Glad you enjoyed it, welcome! :)

[@TurrentWolf]

Working with gear boxes daily i never thought to see them made out of plastic. I've never heard of harmonic drives in my field of gearboxes. The design principle is very similar to cycloidal drive gearbox. neat work!

[@3DprintedLife]

Thank you!

[@formfunction3d247]

Use either a filled nylon like nylonX (carbon fiber) or nylonG (glass fiber) to reduce warping when you do decide to print the new flex spline. It will also add rigidity

[@christopherhurtle7167]

This is the first time I've seen your channel great video subscribed!

[@3DprintedLife]

Awesome, thank you and welcome to the channel!

[@MrDayTwo]

Really enjoyed the video, thank you. You are a real engineer.

[@3DprintedLife]

Thanks!

[@Furzkampfbomber]

I have zero idea about the math, I would not know where to even begin when I had to make something like this and then I would fail again when it comes to the software controlling the arm. And yet here I am, watching and marvelling at all this expertise and at the fact that people are actually making things like this at home. I mean, I have a 3D printer, I am sooo proud about the first thing I've made in Tinkercad myself, a soap holder, and then I see this guy... :D

[@patkirk960]

Excellent work. very helpful to see so many destructive test also

[@3DprintedLife]

Breaking things is my favorite!

[@MauricioHernandez-de8is]

hi bro, that´s a lot of hard work!! thank for sharing your knowledge

[@3DprintedLife]

Thanks glad you enjoyed!

[@aerball]

I create 3d printed torque sockets for capping bottles at work and using a 3/8 inch drive, we are regularly able to place 60 in'lb of force on them without any problems. They obviously wear after a while but we were really surprised at how much they could take for as long as they can take it.

[@lena96969]

This has been my dream project for so long!

[@3DprintedLife]

Well it's open sourced! Play around with it, make it better, or make your own from scratch. Don't let your dreams be dreams! github.com/DDeGonge/OS-ARM/tree/main/cad/HarmonicDrive75mm

[@lena96969]

@@3DprintedLife I know! Thank you so much!

[@narpat007]

great, want to see further progress.

[@dave_jones]

Awesome, the video with the finished arm is going to be insane!

[@3DprintedLife]

Thanks, I'm very excited for it! And thanks so much for the support on Patreon!

[@dave_jones]

@@3DprintedLife Glad to give what little support I can :)

[@3d_davej]

Wow! That was super fun and enjoyable to watch

[@3DprintedLife]

Glad you enjoyed it!

[@PhG1961]

Excellent video, very entertaining and also very well explained ! Really cool stuff !

[@3DprintedLife]

Thank you!

[@wejzu8516]

Amazing project well done

[@waynenewberry1032]

Very Nice! Most will never realize the amount of work and talent it took to do this. Hopefully some sponsors will see this and drown you with new toys.

[@starkosaure7833]

Thank you for sharing!

[@dernicolas6281]

Great design and development. Well done.

[@3DprintedLife]

Thank you very much!

[@laveenkumar5737]

Clear Explanation and detailing

[@3DprintedLife]

Thank you!

[@patricioruiz-tagle9706]

Wowowowowowow. Awesome engineering work

[@soronemus8815]

Impressive work my dude!

[@3DprintedLife]

Appreciate it!

[@Mike-tq9cg]

I just got a harmonic drive from harmonic drive. Without measuring (they are tiny), the teeth do look involute. The drawing and 3d model they gave me doesn't include any info on them, I suspect its their secret. Nice work on this, very impressive to come up with your own new design on something this complicated.

[@3DprintedLife]

Ah awesome, good to have some insider info haha thanks for sharing that!

[@fishemrock]

hey ! great work. Nylon isn't really hard to print. I recently printed Taulman's alloy 910 Nylon on Ender3 v2 using stock glass bed and elmer's purple glue stick. It stuck pretty well without warping. The sample was flat on its long side, a 1 cm by 1cm profile that was extruded for 15cm.

[@sirukin7849]

This is insanely cool!

[@rowbearpucklebuck2331]

I am an old cannon cobbler and pocket watch tinkerer, so this is outside my interests but as an engineer and novice 3d printer, this is wonderful!

[@aspitofmud6257]

Patterns Mom and Dad. Priceless!

[@ChrisMcNeely]

Mad skills there

[@ChadKovac]

This would make a great gate opener!

[@Quork]

If you got delamination problems you can bake prints on the printed. Just cover the print with something (a box/aluminium foil) and set the bed to 80°C then leave it for 30 minutes. I do not know how much this increases strength, but on a basic make 2 parts and try to break both basis it makes a noticeable difference

[@alphonsobutlakiv789]

Built a robotic hand when I was like thirteen, back in like 2008 maybe. It was all wood, with programmable tumblers with a live control override set up like a piano. It's glue didn't hold up to humidity long, so literally just fell apart over a wet summer. It used pull strings and springs, and later bands, very close to how a real human hand works. Can just copy the human body and only run a single moter to bring it to life with this method. To add a computerized element, the tumbler spokes can just be raised and lowered, still powered of the single moter. I wouldn't be surprised if someone else is already building something like it.

[@Calthecool]

9:50 Almost did the good old knuckle slam there

[@patricklaqua5590]

Nice work!

[@ErosNicolau]

Oh boy this video was looong overdue! I'm so tired of seeing all the "creative" minds of KZbin just skimming the HD subject and going for the pot design, while what you're using (called the "pancake") is so much more compact and nicer! I know because I built a full metal one some years ago and have been waiting to see somebody do the 3d-printed pancake too ever since... So good one, bud! 😍

[@3DprintedLife]

Thanks! And oh cool I was wondering if this variation had a specific name haha :D Glad you enjoyed!

[@ErosNicolau]

@@3DprintedLife www.harmonicdrive.net/products/component-sets/pancake/fr-2

[@TeraVoltLabs]

Great work! Much more eloquent of a design than my Lobster Claw Arm :)

[@muggzzzzz]

You could use an ordinary timing belt turned inside out, as a flexible gear ring. You could match two timing belts with slightly different number of teeth to match your gear ratio.

[@uku4171]

I made a wooden robotic camera arm for a school project using DC motors from old power tools (18V and 12V I think). Very powerful, but loud and not very precise. For the gearing I just used a nut and a threaded rod at the end of the tool's gearbox. The threaded rod was good because it also stopped the arm from moving up or down by itself. The arm was pretty bad as the wooden structure was very unstable. It was also very unprecise, but I think that could easily be fixed with a few sensors and software. It cost me about 300$ (including the Arduino and everything else).

[@tablatronix]

I didn't even know these drives existed, fascinating

[@GMC997]

Subscribed! Very helpful information here buddy. Especially if you are on a very tight budget and want to build a robot.

[@3DprintedLife]

Thanks for the sub, and that's the goal!

[@BitSmythe]

This guy: designs, iterates, builds and programs complete, strong robot arm. Me: happy my vase turned out. You go, guy, kudos, cheers and congrats!!

[@3DprintedLife]

Thank you!

[@swannschilling474]

I subscribed for this project!! Since I am building an arm using Cycloidal Gearboxes...but always enger to learn! 😍

[@3DprintedLife]

Awesome, welcome aboard!

[@swannschilling474]

@@3DprintedLife Hope you'll make more on this one...I would really like to try to build one of these too! 😊

[@AmaroqStarwind]

To improve the durability of your prints, you could enable some "elephant's foot compensation" (no, not _that_ Elephant's Foot), and pack your printed part with some sand so that you can temper and anneal it. Don't forget to freeze-dry your nylon filament, immediately store it in a vacuum bag with some desiccant, and when you print with it, feed the filament directly from your dehydrator. Also make sure you have a dehumidifier running in your room during all printing operations, and coat your printed Nylon parts with a hydrophobic substance like Neverwet.

[@Chucklet11]

Found in your discord, this was all printed in PLA! Not sure if you mentioned that in the video, I looked for it but couldn't find it. You should probably put that in the description.

[@harryragland7840]

I recently picked up a few 3 phase BLDC motors that are used in camera gimbals to provide pan and tilt. They have 12 windings and 14 magnets so there are 42 steps to go the full 360 degrees. They were less than $5 apiece. They are quite compact and might be able to be mounted internally in a harmonic drive such as yours. I may have to give it a try. Just to be clear, the way your design works is that the belt moves inside the two cups, but the moving cup has more teeth than the fixed cup.

[@3DprintedLife]

Oooh cool idea!

[@bootlegcaesar7481]

Looks very promising, incredible how much 3d printed parts actually endure before failure

[@3DprintedLife]

It really is, the tech has come a long way!

[@shashvatverma5673]

@@3DprintedLife Bro this is such a sick project love your work

[@JoeWayne84]

Wow man nice job

[@Tormasan]

the Greatest video i ever seen please keep doing this project i want to build the same thing

[@3DprintedLife]

Thank you, don't worry I'm not stopping!

[@paleogeology9554]

You should design a compliant mechanism as the spring per say instead of the belt. It would actually work perfectly for this opperation and give you far better results in your testing right off the bat. Hope it helps ya ;)

[@joemulkerins5250]

I was making planetary gearboxes for my plastic extruder. It kept breaking and eventually reached the limit of the plastic regardless of my design. I only had one stepper driver as well so what I did was just make two them and wired them in parallel. They were nema 17s and the stepper driver was only a 2A but it never popped the driver and never broke the gearbox anymore. Other things broke 😅. I feel your pain in this video with reiterating though. You tend to learn so much from it though. Great video thanks.

[@sKuNKdoSE]

First time here! Really cool video man! I scrolled down and expected more subs than 11.8k! lol ...Here's another one! 👍

[@3DprintedLife]

Oh don't worry, it's at 11.801k now! :D welcome!

[@fonwoolridge]

Impressive work!

[@ghostyFPV]

your willingness to embrace so many failures is what makes you a goat

[@anonymousperson7221]

Hi, I was making my own version of this and was wondering if you could give a full guide on how to assemble

[@bijibijmak]

Fillamentum Nylon CF15 is a pretty good candidate for printing. Not too much shrinkage and very very tough! Since you’re printing round parts The chances would be lower for peeling.

[@oscarsorensen210]

Nylon isn't too bad! Just dry it and it'll print quite nice. Loves to warp though, I found printing draft shield helps, an enclosure would be better.

[@takodragionextream3625]

I like that you show your own failures and go for a lower budget range ,most channels like this try and do it by whatever means possible

[@locomotioncreations]

Great video man

[@JamieBainbridge]

That's pretty interesting. Whiteline's polyurethane blend called includes PTFE (Teflon) so their bushings theoretically become self lubricating in the same way you're using tape here.

[@ytrichardsenior]

You are EXTREMELY patient!

[@3DprintedLife]

Oh, you'd be surprised haha

[@ytrichardsenior]

@@3DprintedLife Well in that case you're a fabulous video editor :) Well done, excellent piece of work, great video.

[@sukhrajhothi1542]

beautifully told design story! :)

[@3DprintedLife]

Thank you! 🙂

[@AkaedatheLogtoad]

Looks like some of the pricing on the arms in the beginning was legit. Rd in a bigger company plus higher quality parts. Really solid work man.

[@Sixfeetund3r]

You make great videos! Keep it up and i bet you'll get way more subscribers

[@3DprintedLife]

Thanks! It's probably not realistic but I'm shooting for that silver play button by the end of the year 🖖

[@flamewave000]

Just want to mention, it makes sense you were getting too much slop with the rubber belt. They're designed to be run in tension and have a certain amount of expansion expected. So without that tension it would flex too well.

[@joshgray1331]

Excellent work!!!

[@3DprintedLife]

Thank you! Cheers!

[@NeoIsrafil]

Oh! Smart! I like the belt idea... but what if we used TPU for the flex spline? This stuff is super resilient and still pretty bendy. I wanna say I'd try tpu for the flex, and resin printed abs-like anycubic resin for the hard parts. Its so tough, but unlike some of the resins I've tried it literally will flex in half without snapping if you make it thin enough to bend. Nutty stuff...

[@deusexaethera]

Neat! If only I needed one for any purpose whatsoever...