Prusa I3 MK2 Z-Axis Improvements

thingiverse

I had noticed two things about my Prusa after many printing experiences. One was the occasional noise when the lead screw hits the top Z-Mount. Sometimes, when rapid reversal from up to down or vice versa, I figured making this more rigid would be a benefit by adding a 608ZZ bearing. The second was that my Z-Height was slightly skewed to the rear of the Y-Axis at the top on a full 200mm height. This meant that my Z-Travel was not truly perpendicular to my bed. I was off about 3-4mm at the top of a 200mm high print. I checked this on a granite table after I printed. So, I wanted to fix both issues at the same time and added the bearing and the adjustable all-thread to get a "perfect" perpendicularity on both sides. I was surprised that my frame wasn't better, but I think the slots in the aluminum frame were somewhat of a culprit. You will need: 608ZZ Bearings X2 each M8x1.25 Threaded Rod 1 Meter - Cut to 430mm (17 inches) X2 pieces M8x1.25 Nuts X8 each M8 Washers X8 each 10-24 Threaded Rod 3 Feet - Cut to 380mm (15 inches) X2 pieces 10-24 Nuts X8 each 10-24 Washers X8 each (not sure actual washer size) Use M8 Threaded Rod to replace original front rods to support two Y_End_With _Cross_Brace. Replace the top Z-Axis supports with new ones with bearings pressed in. Please note that the tension screw for the filament tensioner may contact the right mount if the screw is not turned in a little further than recommended. I adjusted both to be applying equal pressure and have not noticed any issues with extrusion rate. Use a Square on the bed set next to the x-axis rods at the lowest z height, then raise the z axis without moving the square to see the difference at the top. Adjust the 10-24 nuts to set this perpendicular. Then repeat up and down about 3 times until you are satisfied that you are perpendicular on both left and right sides.