3 ms·

I really like this presentation! It’s wonderful. I don’t mean to hijack but I thought this would be an appropriate place to share a photo album of the 3D print

I really like this presentation! It’s wonderful. I don’t mean to hijack but I thought this would be an appropriate place to share a photo album of the 3D printed planetary gears in my open source robot: https://imgur.com/gallery/GqXD2Zj https://imgur.com/gallery/GqXD2Zj I’ve been 3D printing gears for some years now and I want to spread the word that 3D printed gears actually work really well! The gears in the image album above have been operating on that robot for over a year now and they’re showing no real signs of wear. It can be really fun to get a 3D printer and design a little gear assembly. Once you’re comfortable with gears you can use cheap motors to make something that moves. Find a way to drive it with Python from a raspberry pi and you’re on your way to making a robot. :)

outworlder 7y ago
Which material are you using the print the gears?
- TaylorAlexander 7y ago
  PETG. Specifically it would either be Hatchbox PETG or PushPlastic PETG.
  - djmips 7y ago
    Have you considered fibre reinforced plastic? I'm not an expert but I'm curious if that's a good option.
    - TaylorAlexander 7y ago
      I’ve seen fiberglass reinforced nylon gears used with success in commercial injection molded gearboxes. It can definitely help by increasing gear stiffness. However 3D printing with fiberglass causes rapid nozzle wear, and recently people are saying that fiberglass reinforced 3D printing filaments represent a human hazard. Since I’ve managed to get my gears to work without reinforcement, I’ve not tried it. One thing I do with printed gears is make the gear teeth much larger than would be strictly needed in an injection molded solution. This lets me deal with reduced material performance compared to injection molding.
      - deleted 7y ago
        [deleted]
      - double0jimb0 7y ago
        Have printed many spools of CF and glass filled nylons using nozzles with tips made from ruby. Check out “Hardcore Ruby” nozzles, now there are even diamond nozzles. I print with 0.25mm nozzle in nylon, fine enough for Module=1.5 teeth. A 0.15mm nozzle would make an acceptable Module=1 gear I would guess.
        TaylorAlexander 7y ago
        Yes I’ve seen ruby nozzles. Expensive though. I actually print with a 1.2mm nozzle as I want to print big parts. I’ve even got the e3d Supervolcano hot end. :)
      - zxzx 7y ago
        You might be interested in resin casting technique. It gives amazing results. Lcamtuf wrote a whole series about this: http://lcamtuf.coredump.cx/gcnc/ch1/ http://lcamtuf.coredump.cx/gcnc/ch1/ and very nice article for make zine: https://makezine.com/2014/03/21/resin-casting-going-from-cad-to-engineering-grade-plastic-parts/ https://makezine.com/2014/03/21/resin-casting-going-from-cad...
  - huseyinkeles 7y ago
    I'm very new into 3D printing scene, so far only been printed with PLA. Also have some ideas that includes some motorised parts with gears. Do you think PLA is a bad choice for this?
    - TaylorAlexander 7y ago
      For gears in general PLA is fine. If they have a lot of friction they will heat up and that’s where the PLA could fail. But PETG is very easy to print with! You’d need to adjust nozzle and bed temp but it prints very nicely. :) PLA is fine to start with though. If you see failures you can switch.
StavrosK 7y ago
That project looks great! I'm very tempted to start building this because of how good it looks, but I know it would take lots of time and effort, even with the designs already available. As an aside, would something like https://www.makerfol.io/ https://www.makerfol.io/ be useful for your build log? I see many people using imgur for this but it's always struck me as suboptimal.
- TaylorAlexander 7y ago
  Thank you! It’s certainly an involved project. I recommend starting by building one motor and gearbox assembly and getting control working from python. If you can get that far you can build the rest! And the website you linked looks nice. There is also hackster.io and hackaday.io. While those sites are fine, it becomes one more thing to update. I prefer imgur for simple photo albums as that integrates well with reddit, my primary promotional place. Imgur actually works really well for me there. And then my real build updates are on my YouTube channel. And I have my own website where I try to throw everything. So I end up trying to funnel people to my website and just using whatever media hosting makes sense for that particular media.
  - StavrosK 7y ago
    That makes sense, thanks! Regarding the build, I didn't see any information regarding the control system on the material I saw, but I probably wouldn't want to make it as autonomous as you have. I'd probably connect an ESP8266 as the controller and a receiver for my RC radio and control it that way. Out of curiosity, is there more detailed information about the controller somewhere?
    - TaylorAlexander 7y ago
      Well do you mean the motor controller, the control computer, or the remote control? I’ve got some info on the motor controllers I’m using: https://reboot.love/t/vesc-mods-for-robotics-use/ https://reboot.love/t/vesc-mods-for-robotics-use/ The control computer is a raspberry pi running python. It looks like I’ve not committed the code in a while, but this repo may be helpful: https://github.com/tlalexander/rover_control https://github.com/tlalexander/rover_control Though for the above, I’ve recently found that I can use velocity control on the VESC, which is easier than doing velocity control on the Pi as I had done in that repo. For the wireless remote control I use, it’s my own design and they’re not for sale or well documented. I’d recommend any wireless controller that you can read in python. The software should be pretty simple now that I’ve switched to velocity control mode. You just need to read a joystick and convert that to velocity commands for each VESC. Technically even the VESCs could do that onboard if you wanted to modify the firmware. But if you can drive the VESC from an esp32 that would work too.
MayeulC 7y ago
Hey, nice project :) A few friends were experimenting with 3D-printed gears for their robots, I've advised to switch to helical gears as these should make less noise, and less prone to wear (since the load never happens on a single teeth, but is transfered progressively). Of course, that creates axial load, which might or might not be an issue (and countered with a second cog), and complexify assembly, especially for planetary gears. But if you try (or already have) them out, let me know. On our part, the test have proved successful, but we're not looking at tens of kilometers, and mostly print PLA. To clarify why they aren't used more, their production process is traditionally more complex, but that doesn't happen with additive manufacturing. I'd also guess that the teeth shape makes them more robust than conventional filling, and more evenly distributes force on the layer joints.
- TaylorAlexander 7y ago
  Thanks! I’ve used helical gears in some of my projects. i didn’t have a specific rationale for not using them in Rover, except it’s more CAD work in my particular CAD program. But they can be nice! Rovers gears certainly do make some noise.

outworlder 7y ago

Which material are you using the print the gears?

TaylorAlexander 7y ago
PETG. Specifically it would either be Hatchbox PETG or PushPlastic PETG.
- djmips 7y ago
  Have you considered fibre reinforced plastic? I'm not an expert but I'm curious if that's a good option.
  - TaylorAlexander 7y ago
    I’ve seen fiberglass reinforced nylon gears used with success in commercial injection molded gearboxes. It can definitely help by increasing gear stiffness. However 3D printing with fiberglass causes rapid nozzle wear, and recently people are saying that fiberglass reinforced 3D printing filaments represent a human hazard. Since I’ve managed to get my gears to work without reinforcement, I’ve not tried it. One thing I do with printed gears is make the gear teeth much larger than would be strictly needed in an injection molded solution. This lets me deal with reduced material performance compared to injection molding.
    - deleted 7y ago
      [deleted]
    - double0jimb0 7y ago
      Have printed many spools of CF and glass filled nylons using nozzles with tips made from ruby. Check out “Hardcore Ruby” nozzles, now there are even diamond nozzles. I print with 0.25mm nozzle in nylon, fine enough for Module=1.5 teeth. A 0.15mm nozzle would make an acceptable Module=1 gear I would guess.
      - TaylorAlexander 7y ago
        Yes I’ve seen ruby nozzles. Expensive though. I actually print with a 1.2mm nozzle as I want to print big parts. I’ve even got the e3d Supervolcano hot end. :)
    - zxzx 7y ago
      You might be interested in resin casting technique. It gives amazing results. Lcamtuf wrote a whole series about this: http://lcamtuf.coredump.cx/gcnc/ch1/ http://lcamtuf.coredump.cx/gcnc/ch1/ and very nice article for make zine: https://makezine.com/2014/03/21/resin-casting-going-from-cad-to-engineering-grade-plastic-parts/ https://makezine.com/2014/03/21/resin-casting-going-from-cad...
- huseyinkeles 7y ago
  I'm very new into 3D printing scene, so far only been printed with PLA. Also have some ideas that includes some motorised parts with gears. Do you think PLA is a bad choice for this?
  - TaylorAlexander 7y ago
    For gears in general PLA is fine. If they have a lot of friction they will heat up and that’s where the PLA could fail. But PETG is very easy to print with! You’d need to adjust nozzle and bed temp but it prints very nicely. :) PLA is fine to start with though. If you see failures you can switch.

StavrosK 7y ago

That project looks great! I'm very tempted to start building this because of how good it looks, but I know it would take lots of time and effort, even with the designs already available. As an aside, would something like https://www.makerfol.io/ https://www.makerfol.io/ be useful for your build log? I see many people using imgur for this but it's always struck me as suboptimal.

TaylorAlexander 7y ago
Thank you! It’s certainly an involved project. I recommend starting by building one motor and gearbox assembly and getting control working from python. If you can get that far you can build the rest! And the website you linked looks nice. There is also hackster.io and hackaday.io. While those sites are fine, it becomes one more thing to update. I prefer imgur for simple photo albums as that integrates well with reddit, my primary promotional place. Imgur actually works really well for me there. And then my real build updates are on my YouTube channel. And I have my own website where I try to throw everything. So I end up trying to funnel people to my website and just using whatever media hosting makes sense for that particular media.
- StavrosK 7y ago
  That makes sense, thanks! Regarding the build, I didn't see any information regarding the control system on the material I saw, but I probably wouldn't want to make it as autonomous as you have. I'd probably connect an ESP8266 as the controller and a receiver for my RC radio and control it that way. Out of curiosity, is there more detailed information about the controller somewhere?
  - TaylorAlexander 7y ago
    Well do you mean the motor controller, the control computer, or the remote control? I’ve got some info on the motor controllers I’m using: https://reboot.love/t/vesc-mods-for-robotics-use/ https://reboot.love/t/vesc-mods-for-robotics-use/ The control computer is a raspberry pi running python. It looks like I’ve not committed the code in a while, but this repo may be helpful: https://github.com/tlalexander/rover_control https://github.com/tlalexander/rover_control Though for the above, I’ve recently found that I can use velocity control on the VESC, which is easier than doing velocity control on the Pi as I had done in that repo. For the wireless remote control I use, it’s my own design and they’re not for sale or well documented. I’d recommend any wireless controller that you can read in python. The software should be pretty simple now that I’ve switched to velocity control mode. You just need to read a joystick and convert that to velocity commands for each VESC. Technically even the VESCs could do that onboard if you wanted to modify the firmware. But if you can drive the VESC from an esp32 that would work too.

MayeulC 7y ago

Hey, nice project :) A few friends were experimenting with 3D-printed gears for their robots, I've advised to switch to helical gears as these should make less noise, and less prone to wear (since the load never happens on a single teeth, but is transfered progressively). Of course, that creates axial load, which might or might not be an issue (and countered with a second cog), and complexify assembly, especially for planetary gears. But if you try (or already have) them out, let me know. On our part, the test have proved successful, but we're not looking at tens of kilometers, and mostly print PLA. To clarify why they aren't used more, their production process is traditionally more complex, but that doesn't happen with additive manufacturing. I'd also guess that the teeth shape makes them more robust than conventional filling, and more evenly distributes force on the layer joints.

TaylorAlexander 7y ago
Thanks! I’ve used helical gears in some of my projects. i didn’t have a specific rationale for not using them in Rover, except it’s more CAD work in my particular CAD program. But they can be nice! Rovers gears certainly do make some noise.