Compact Planetary Gearbox
Derived from
Description
Version 2
Now supports an M8 bolt for the output by default.
Changing the output size no longer requires reprinting the entire assembly - just print the top half of the planet frame, and the cover.
If you want the M6 version, print m6_output.stl as well.
If you've already printed the M6 version, and want to convert it to M8, print m8_output.stl.
Warning! This is difficult to print. Unlike Jag's design it doesn't have a lot of overhangs, but the gear teeth require a lot of precision.
Instructions
One of the 608 bearings goes on the inside of the case. The other should be holding the end of the bolt in place, with a locknut, or a pair of nuts.
I spent quite a lot of time just slicing it and looking at slic3r's output before committing it to plastic, and still printed it 4 times before I was happy with how it printed. Expect to have to print the gears slowly - I printed mine at 20mm/min, with a .35mm nozzle and .25mm layer height.
The .scad is fairly parametric, so you can adjust the number of annulus and planet teeth to produce different (and probably unprintable) gear ratios.
This is marked as a work in progress, because I intend to use it to drive an extruder, and still need to design the extruder body.
Vitamins:
3 M3x12 Socket Head Cap Screw
4 M3 Nut
1 M3x6 Set Screw
4 M3x35 Socket Head Cap Screw
1 M8 Hex Head Cap Screw or 1 M6 Hex Head Cap Screw
2 608ZZ (8x22x7) or 126ZZ (6x12x4) Ball bearing.
1 M8 or M6 Nylok Nut
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I would love to see some devices and extruders that incorporate your planetary gearbox :)
Slic3r 9.7's ability to fill narrow areas makes me think this could be printed and made strong sometime in the near future :)
hey i just built my own 3d printer, and even with a .35mm hot end, the sliced profile comes out with the planets only being 1 perimeter thick. is there any way you can seperate the pieces, so i can experiment, with different slicing profiles for the planets?
Hi,
Did you finally build a complete extruder based on this design? I would be interested...
Thanks.
I printed it and it worked perfectly straight away with no cleanup.
I have one currently on the extruder of my 3d printer and it has performed flawlessly. I printed it out of ABS .
It completed a 13 hour print with no problems.
Best and most practicle thing I have ever found on thingiverse.
Thank you for designing such a great thing!!!!! Awesome
Printed this last wkd. Looks and works great. I print with a larger 3D printer and printed this in Nylon 6/6 because it's very slippery and will require no lube.
Thanks.
I hate to be the only idiot to ask this, but... how do the printed pieces actually go together? I have some theories, but i would hate to assemble it wrong and break something in the process (it was a solid 8 hour print... seems to have worked fine on the first go though).
Install the output bolt into the top of the planet frame. install the planets into the bottom of planet frame. Attach the bottom of the planet frame to the top frame using M3x12 screws and nuts.
Install the bearing into the cover. Run the output bolt through the cover. Insert the planet frame into the annulus (ring) gear, aligning the teeth of the gears.
Attach the sun gear to the motor.
Attach the gearbox to the motor using M3x35 screws, making sure that the teeth on the sun gear are
aligned to the planets, and that the sun gear has adequate clearance.
Wow that is spectacular. I have been chewing over ideas for this sort of thing for a long time. Principlay for a revised extruder. An here you have done it. You are truly a star. 8-)
News on the planetary extruder front:
The prototype finished a 6 hour print last night, but managed to break the sun gear today.
I may have to increase the housing size to 50mm in order to beef up the gears.
More news:
I've been able to produce a stronger sun gear, by tweaking the diametral pitch of the gears so that the inner and outer extrusions between the gear teeth and the bore are touching.
Unfortunately, with the current version of slic3r, this ends up making the model be *very* slicing settings dependen
t, and I suspect that a .5 nozzle version with the same gear ratio may be impossible.
Hmm, don't believe its possible to print this using slic3r and a 0.5mm nozzle.
Reason being no matter how i slice it, the planet gears are only 1 wall thick, as theres insufficient space for 2 walls. As such it doesnt really work since theres a huge gap in between the wheel hub wall and the sprockets.
This printed out great for me on my TOM mk6. I will mount it on a stepper today and upload a photo.
Thanks for this thing!
Very awesome! I printed mine all in one go. I had to clear out the insides of the small gears with a 6.5mm drillbit, but the rest went together smoothy. I didn't have the M6 bolt, or MR-126 bearing, so I couldn't construct the output side, but everything else moves smoothly. Nice job!
More from raldrich
I printed it and it works as my extruder for quite while now no cleaning at all nozzle J head 0.35mm sliced in kisslicer printed in PLA on prusa mendel, extruder is using YRU hobbed bolt type, right now I'm working on my own planetary gearbox because this one is too long and a bit to fragile while i can use box like 60x60mm it has to be shorter. Overall great design