Having been viciously nerd-sniped by The Great Dragorn of Kismet, I’m in the process of building a Prusa MK4 3D printer with an MMU3. This has been a generally pleasant experience, although I am beginning to loathe Genuine Haribo Goldbären.
Anyhow, the Y axis motor position puts the belt too close to one side of the pulley, with no further adjustment possible:
The stepper motor stator laminations are the striped gray area on the far left, the 3D printed motor mount is the striped black area on the right, and the belt pulley is snugged up against the motor as far as it can go on the shaft.
Pushing the motor a little more to the left requires a shim:
Rather than fiddle with scanning the motor mount, I imported its STL model from the Prusa MK4 files:
Importing the STL into OpenSCAD and converting the motor face into an SVG file is basically a one-liner:
projection(cut=true)
translate([0,0,-5.0])
import("/mnt/bulkdata/Project Files/Prusa Mk4/Calibration/y_motor_holder_R3.stl");
Import the SVG into LightBurn, round the corners a little, set it up for 1.5 mm Trocraft Eco, Fire. The. Laser. and it fits perfectly and stands out nicely:
Having the right tools for a job makes it easy …
The Smell of Molten Projects in the Morning 
Comments
6 responses to “Prusa MK4 Y Motor Shim”
Why do you want to be able to use multiple filaments in one print?
Labeling is a definite win:
I’m also following Mad Phil’s advice: “When you buy a tool, get all the options, because they won’t be available later when you need them.” :grin:
Laser avoids loop of needing to print parts to fix the printer.
I’ve fulfilled the prophecy: the necessary number of 3D printers is one more than you currently have.
Ah, I am up to 3 and a half (half = older RepRap half finished), one Ender 5 pro works, the other needs a rebuild and the little Duinotech has developed a crack in the base support plastic casing… They will all get fixed eventually…
[…] have the distinction of being the first “real” objects from the Prusa MK4. All my hard-won knowledge of forcing solid models into reality through a 3D printer is obsolete: […]