New Proxxon MF70 CNC Conversion Kit

thingiverse

This is my own CNC conversion for the popular Proxxon MF70 micro milling machine. I’ve managed to reduce backlash to around 0.02-0.03mm. It uses the Nema 17 stepper motors. The main idea of this conversion was to use the stepper motor as the fixed point of each axis and get rid of all the intermediary bearings, flexible couplings, etc. In my build, I also replaced the original nuts with 3D printed parts, which I’ve tapped by hand, to the same thread as the leadscrew. This part is optional, as you may very well use just the mounting assemblies for the motors and the couplers, and keep the original nuts if the full assembly looks too difficult for you. Here are my own build videos, to help you with your own conversion: https://www.youtube.com/playlist?list=PLrL54CFyas-dFN4LSHjTCGW8CWj5fjjr9 Here is the list of parts with some explanations. I printed all parts in PLA, 0.2mm layer height, 100% infill. - Z_Bridge.stl, X_Bridge.stl, Y_Bridge.stl - These are the basic assemblies for each axis. - Nema_17_plate.stl – This part is the same for all three axis and allows you to mount the motor first to a plate, then to the previous assembly - Nema_17_Adjustment_ring.stl - This is a critical part, which allows you to take out the axial play in the Nema 17 stepper motor. It replaces the wave washer inside the motor. You will first have to remove the wave-washer, measure the play, and print the adjustment ring to the correct height. In my case, the play was different for each of the three motors, so beware. - Coupler_5_to_4_5mm.stl - Use this for the Z-axis and if you plan on keeping the original M6 leadscrews for the X-Y table. - Coupler_5_to_8mm.stl - Use this if you plan on upgrading to an 8mm leadscrew for the X-Y table. For this project to work properly, the leadscrew needs to be reasonably straight and aligned with the motor shaft. If this isn't the case, you can do it by hand with a bit of time and patience. This next part is optional. These are the nuts for the Z-axis and X-Y table, which you can print in PLA. You need to tap the holes for the leadscrews to the correct thread. - XY_Cross_nut_6mm.stl - If you plan on using the original M6 leadscrews - XY_Cross_nut_8mm.stl - If you plan on upgrading to 8mm ACME leadscrews. - XY_Cross_nut_cutting_stencil_.stl - To install the previous part, you need to make a cut in the X-Y table carrier. I made this stencil to facilitate the cut. - Z_nut.stl - this is screwed directly to the milling head. Good luck and if you have any questions, I’ll try to answer as well as I can.