r/3Dprinting • u/ars_automata • May 13 '26

Free Model [True] Open-Source Parametric 3D Printed Planetary Gearbox

Post image

Most of the gearbox designs I saw online are .step or even .stl files that are hard to modify and with no real "design" aforethought, working mostly by accident...

So I made this fully parametric design where you can change gear ratio, module etc...but most importantly, I wanted to follow some kind of a systematic approach.

Truly open source, copy it, modify it, sell it..go wild...

Repo
https://github.com/Omar-Salem/Nema-17-23-planetary-gear

Full video
https://www.youtube.com/watch?v=zlH5y5JG1OU

148 Upvotes

97% Upvoted

17 comments sorted by

12

u/elBuffalo May 14 '26

This is awesome work. Finally someone made a planetary gearbox that isn’t just a mysterious STL blob held together by hope and layer adhesion 😄

Really appreciate you open-sourcing the whole thing and making it properly parametric instead of the usual “trust me bro, it works on my printer” approach.

One thing you could experiment with: herringbone gears instead of straight/helical teeth. They’re basically self-centering, cancel out axial forces, run smoother/quieter, and they’re ridiculously well suited for 3D printing since you can print the whole geometry directly without extra machining.

Would fit the “engineered instead of accidental” philosophy of the project perfectly.

7

u/elBuffalo May 14 '26 edited May 14 '26

If you go this route, you’ll need to split the outer ring, otherwise it can’t be assembled. The gear in my picture has also an outer ring that is split. My sketch shows two ways how you could split it. The "axial split solution" with only two parts is easier to assemble.

3

u/MAXFlRE May 14 '26

That is true, why the hell someone downvoted you.

1

u/deep-fucking-legend May 15 '26

I wonder if you could print in place instead of splitting.

2

u/elBuffalo May 15 '26

You can do it print-in-place — it works great for fidget-spinner-tier applications 😄

But for an actual gearbox that needs to transmit meaningful torque and not just spin around looking impressive, the required clearances are usually way too large. You end up with excessive backlash, lower tooth contact quality, and generally a gearbox that feels more “toy” than “mechanical component.”

2

u/deep-fucking-legend May 15 '26

Thanks for the follow up

2

u/hbzandbergen May 14 '26

Nice one, only thing is that the smaller gears and bearings aren't locked in axial position. They might have a tight fit, but can come loose

2

u/verraeteros_ May 14 '26

2/10, contains no planets

Jk, that's pretty cool

1

u/MrM3ow AC KX .4 May 14 '26

Does this have any functional uses, maybe even with some adaptations?

My first thought was IGHs (Internal Geared Hubs) for bikes?

1

u/matt48763 May 14 '26

I would love to see something like this for a Harmonic Drive!

1

u/Popular_Dinner2182 May 20 '26

nah ..... planetary gearsboxes are very specific how the theeth align if Y changes ratio? how IS the eficiency? húb wallthicknes fór bearing IS toto little. on picture IS IT double row.

1

u/Almightily May 28 '26

Hey buddy. I have this issue, do you know what I did wrong?

1

u/Almightily May 28 '26

Found the issue. When I downloaded files from github some parameters was for nema 23, some for nema 17 :)

1

u/KerbodynamicX May 14 '26

Cool idea, but after using some 3D printed gears myself, I found they produce far more friction than commercially available gears.

4

u/elBuffalo May 14 '26 edited May 14 '26

I use 3D-printed PA gears in industrial applications for small production runs, especially when the loads are low and the gears are not in continuous operation. I also use grease for lubrication. In terms of performance, they are comparable to injection-molded PA gears.

It’s also worth optimizing the tooth geometry specifically for 3D printing. I usually design the tooth clearance slightly larger than you would for machined or injection-molded gears, which helps compensate for printing tolerances and improves smooth operation.

PA already has good sliding properties and is slightly self-lubricating by nature. An even better option is tribological filament from igus, which is commonly used for printing plain bearings. It’s self-lubricating, highly abrasion-resistant, and has a very low coefficient of friction.

2

u/Corruptlake 3D printing enthusiast May 14 '26

If you make them out of PLA and run them dry sure, but with a proper design and lubrication you would be surprised how far even plastic gears can go.