This planetary gearbox has been designed to reduce the backlash and hysteresis but at the same time to be easily printed and assembled.

Three "planets" and the "sun" are contained inside a 60 teeth corona providing a total 1:5 reduction.

It has been proved that the 1:5 ratio has a very good balance between speed and accuracy when using the regular 1.8º/step NEMA17 motors.

The teeth of the gears have been modeled so they can be printed using a 0.4mm nozzle (no sharp edges) STEP FILES AVAILABLE here: https://www.thingiverse.com/download:8216087

Print the orientating the GEARs (SUN and PLANETs) so the narrow part is touching the heated bed. Doing that, the "elephant foot" effect due to an overheated bed will not deform the contact surface of the GEARs.

Print the GEARED CASE with SUPPORT and oriented as shown in the image portfolio.

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Elements to be printed:

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3x PLANETS

1x SUN

1x UPPER STRUCTURE

1x GEARED CASE

1x GEARBOX BASE

1x MOTOR-PLATFORM ADAPTER

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BOM (Bill of Materials)

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1x 6002RS Ball Bearing

4x 623ZZ Ball Bearing

7x M3 20mm bolt

4x M3 10mm bolt

3D printed parts

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Comments:

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After many, many sets of 3D parts printed, we got to the conclusion that it is impossible to replicate the printing accuracy when using different brands of plastic filaments or 3D printers.

It will depend even on the nozzle diameter you are using or layer height. So, as we really wanted a very precise and backlash-free gearbox, we have designed two different sets of gears.

You will have to print both and select the best combination of SUN and PLANETS.

STL files:
You will find 2 sets of PLANETs and SUNs. Named as PLANET 3.15 and PLANET REGULAR, the same goes for the SUN: SUN 3.15 and SUN REGULAR.

You will have to print 3 planets and one sun for a complete set of gears. But, as we really want to reduce any gap between the gears to zero, print 3x PLANET 3.15, 3x PLANET REGULAR + 1x SUN 3.15 and 1x SUN REGULAR.

Depending on the printing accuracy, you may need to combine the PLANETS of one SET with the SUN of the other.

If you are using a resin printer for the GEARs, select the PLANET 3.15 and SUN 3.15 STL FILES

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NEMA17 stepper motor Planetary GEARBOX 1:5 reduction

0.2mm layer, 2 walls, 15% infill