Printing really tiny Nylon (or PLA) gears... ID = 2.5mm; OD = 4mm; 12 teeth
One of my next projects was to try to print some gears to replace cracked gears on some N-scale locomotives (a chronic problem of some brands from specific eras). I figured I would do a sanity check first before I did too much work on this since the gears are sooooo small. Can print a viable gear this small?
The gears have an outside dimension of 4mm and an inside dimension of 2.5mm with 12 teeth. I think I could make the gears at least 3mm wide (almost as wide as current gear + axle cuff).
Here are some pictures of the gear I need to replace: https://photos.app.goo.gl/grPGXcznQbBp4crK9
Some additional info -- I have a .25mm hardened steel nozzle, .25 copper alloy nozzle, and a .15mm brass nozzle available. I had assumed it would be better to do these out of Nylon but this part of the engine does not get hot so maybe PLA would be an option (since I could use the smaller brass nozzle...?)? I have Nylon, ABS, PLA, & PETG filament available...
In case models / makes matter on parts this is what I have:
- .25mm Hardened Steel Nozzle - https://www.matterhackers.com/store/l/e3d-v6-extra-nozzle-hardened-steel-1.75mm-x-0.25mm/sk/M5NHW8AK
- .15mm Brass & .25 Copper Nozzles - https://www.matterhackers.com/store/l/e3d-v6-extra-nozzle-pro-pack-175mm/sk/MAMCGPVZ
- Nylon - https://www.matterhackers.com/store/l/black-pro-series-nylon-175-3D-printer-filament/sk/MCR8GQZT
- PETG - https://www.matterhackers.com/store/l/petg-red-high-strength-filament-1.75mm/sk/M7M5T2P3
Thanks in advance for advice...
RE: Printing really tiny Nylon (or PLA) gears... ID = 2.5mm; OD = 4mm; 12 teeth
I've done similar thing and I would recommend to use Nylon:
https://www.instagram.com/p/B2GTdi9DjIO
As this part is very small, only one outer layer was possible with 0.4 nozzle. But with Nylon it worked perfectly fine. I think your part is a little bit smaller, so maybe you would need to use 0.25 nozzle. Make also sure to use at least 50% infill. But beside of that I see no issues why it shouldn't work.
Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram
RE: Printing really tiny Nylon (or PLA) gears... ID = 2.5mm; OD = 4mm; 12 teeth
Which online gear designer / generator do you guys recommend?
I have tried a few but I am struggling to make them work (could not find any that let you input diameters and number of teeth instead of other settings I don't know since I am copying gears, PrusaSlicer would not open one STL I created, and my first print came out terrible from one I got to work).
RE: Printing really tiny Nylon (or PLA) gears... ID = 2.5mm; OD = 4mm; 12 teeth
@mac-phd
Did you manage to print that gear? What equip do you need to print something so small? I need exactly same one to the AF mechanism of the old Sigma lens - impossible to buy anywhere...
RE: Printing really tiny Nylon (or PLA) gears... ID = 2.5mm; OD = 4mm; 12 teeth
@polak-jn
I did not get it to work -- I tried a few times but the resolution is not high enough with my printer w/ .25mm nozzle. I have a .15mm nozzle that I might try but I think that it might require UV resin type printing.. some people posted they were able to do that for larger scale trains w/ UV + liquid resin approach.
RE: Printing really tiny Nylon (or PLA) gears... ID = 2.5mm; OD = 4mm; 12 teeth
I've had good luck with the 'Involute Gear' function in the Freecad Part Design workbench.
The smallest one I've made, however, has about a 6mm outside diameter with an 8mm extension for a 4mm shaft. This printed just fine with Hatchbox PLA and meshes with a much larger gear. Standard .4mm nozzle. I would, intuitively, think that this is approaching the limit of a successfully-printed gear of this type with this equipment and nozzle.
