Z-motor brake that prevents build plate from sinking by it's own weight, when power is off the Z-stepper. This can be useful during filament change and recovery after power loss.
(A version for Ender-4, Integrated with Z-motor mount, can be found at https://www.thingiverse.com/thing:3449383)
Brake arms are mounted floating, so there should be no influence on printing quality.
Assembled Z-Motor Brake with 2 x M3 x 18 and 2 x M3 nuts. Be sure everything moves freely.
Unscrew two of the M3 screws that hold the NEMA17 stepper motor.
Mount the assembled Z-Motor Brake with the screws. You may need a couple of longer screws.
Place a spring on the tip of the two brake arms. It should only apply enough force, to prevent the build plate to sink by it's own weight.
1 x Stock Mount.stl
1 x Break Shaft Lid.stl
2 x Breake Arm-XX.stl (where XX is the diameter of the coupler on the Z-axis)
2 x M3x18mm
2 x M3 nuts
1 x Spring of some kind, that pull the brake arms gently together. Only a low force is needed.
You may also need 2 x M3 screws at bit longer then the ones used to mount the stepper motor.