Ender 3 Pro Z-Axis Stepper Motor Planetary Gear Upgrade

thingiverse

Z-Axis Stepper Motor Planetary Gear Upgrade **What this mod does:** The Z-axis stepper motor works at 1.8° steps, with a quad threaded lead screw that raises the X gantry by 8mm per revolution. 200 steps in a full circle, with 0.04mm per full step. The sun and planet gears have 12 teeth, and the ring gear has 36 teeth, resulting in a planetary gear ratio of 4:1. **Files:** https://www.thingiverse.com/thing:4149689 **Buildplate arrangement:** https://i.imgur.com/pZ9cevi.jpg To minimize backlash, there is very little gear clearance, 0.04mm. https://i.imgur.com/Buexshp.jpg I was able to print the model as is with a 0.2mm nozzle and 0.12mm layer height. If you have any trouble, play with the [Horizontal Expansion](https://ultimaker.com/en/resources/52836-shell) setting in Cura. There is more clearance, 0.06mm, between the carrier axis and the planet gears to prevent binding and breaking. They should move freely. Test fit the print. https://i.imgur.com/cbMc2Pt.mp4 **Installation:** The mod takes the place of the Z-motor bracket and the lead screw coupler. So remove those first. You don't have to remove the X-gantry from the printer, but to prevent it from falling, tilt the printer back or on its side before removing the leadscrew. We'll be reusing the 2 M3x16 pan head screws, and 2 M4x18 flush head screws that go through the Z-motor bracket so set those aside. Optionally, use two additional M3x16 screws to hold the planet gears in place. Attach the lead screw to the mod's threaded rod and secure it with a clip or zip tie. Ensure the leadscrew is properly seated on the mod's lead screw shaft. Secure the extruder and hotend to the X-gantry's frame, making sure they are level and securely attached. **Notes:** At 0.01mm height * 0.2 nozzle width * 1000 length = 2mm³ of plastic. With 1.75mm diameter filament, that's 0.83mm of filament to print 1 meter. My DND mini's head may be only 3mm wide. That's 0.00249mm of filament. Two and a half microns -- that's a small bacterium! I'll probably need a geared direct drive extruder upgrade soon, but that seems too heavy for the far side of the X-gantry. To help with printing: 1. Align the objects closer to the left side of the build plate where the leadscrew is. The right side is wobbly. 2. After preheating, level over the bedsprings instead of over the corners of the buildplate. Regarding X gantry speed. After setting M92 Z1600, the x-gantry moves up and down as fast as it used to. To quickly raise or lower the x-gantry, pull the leadscrew and carrier out of the planet gears, spin it, then reset it as necessary. What if I upgrade my leadscrew to a single thread to achieve the same effect? That's a valid solution. This mod is probably not for miniatures. The Ender unmodded can print 0.02 which satisfies the resolution I need and the print time is already getting excessive. Here, the Aarakocra was printed at 0.04mm layer height and the Dwarf at 0.02mm. https://i.imgur.com/YelrihX.jpg For whatever purpose this mod serves, I now have it in my toolkit.