So lately you may have heard about the trend in swapping out the extruder motors on the MK3 from the stock LDO motors to the newer fancier Moons motors. Why? One of the artifacts that can be pretty gross and make out prints not look super sexy is poor linearity or moire in the print. For a long time this was thought to be an issue with the Trinamics 2130 steppers and I still believe this to be the case but only that the Trinamics steppers Stealthchop mode just doesn’t play well with certain windings or levels of back EMF from certain motors.

I know this sounds like a scary and expensive fix but there is hope on the expensive part. We don’t know all the motors that work better with the Trinamics different modes so more testing would be needing and this is where the internet hive mind can come together and test differs motors. I personally choose Moons because of their reputation as one of the best motors on the market and really all I wanted to do is see how well better motors work. I was definitely not expecting what I found out.

So the MK3 is pretty silent in normal mode but these motors are on a new level of silent. Swapping the X and Y axes results in snappier and quieter movement which was pretty astonishing. The only real benefit I saw from tech X and Y motor swaps was the snappier more precise movement. Overshoot seemed less and overall the printer was better but not nearly $80 better. Did I mention these run $36-$40 each?

I don’t recommend the X and Y motor swaps unless you really want to but I do recommend the Extruder motor swap. Why? It solves an issue that many have which is moire in the prints. Basically an angular pattern looks repeated over the entire surface of the print. If you looks closely at the two prints you’ll see one has almost an angular look to the layer lines. This is was the ECORRECTION settings were supposed to fix but overall they mostly reduced the issue or were too difficult to tell any difference. The print on the left is Moons by itself with no correction and it’s completely missing the strange unexplained lines from the print on the right. Both were using the same filament and same gcode just a different motor.

The swap isn’t going to be easy but it gives you time to do a few things. I highly recommend upgrading to the R3 extruder parts Prusa just launched so print those before doing the motor swap since we already have to dig inside and take nearly everything apart. I also recommend swapping out the not so cool spiral cable wrap with a 3/8″ braided wrap-around sleeve because it’ll put less stress on the cables. You’ll also need some proper cable to connect your motor to the Einsy board. I went with these BiPolar Stepper Motor Cables but you’ll need to do a little surgery to make them work properly.

We have our motor, we might have our new cable cover, we may even have the new R3 extruder parts, but we still need to make sure the wires are correct. If you purchases the same Yotino brand cables as I did all you have to do is swap the green wire for the red wire. You can do this simply by using a small thin blade or tweezer to lightly pull back the the little tab that hold the connecter in place for each wire. Don’t pull back too hard or it may break. My recommendation is to push the wire forward, pull the tab back slightly, and gently pull the cable out of it’s home. Do this for both the Green and Red wire. To get them back just insert and they will lock right back into place all happy and cozy. Double check and make sure the wires are in the correct order now. With the tab side facing you the order should be Red, Blue, Black, Green. Any other combination is wrong. See photos for correct orientation and color pattern before plugging anything in.

Now that you have everything ready you are ready to take apart your extruder and do all of the necessary swapping and such to upgrade from the LDO motor to the Moons motor. Good luck and may your rebuild go smoothly!