Suggested Y-Axis Motor Wiring Mod  

Suggested Y-Axis Motor Wiring Mod

One of the not-well-thought-through aspects of the Mini's design is the routing of the Y-axis motor wiring. I bought two factory-assembled units, both of which have this shortcoming. There is a cosmetic issue in that it looks a little messy but there is also the operational issue that with careless moving and transportation, the wire bundle can become "snagged" on surrounding obstructions or projections that can lead to damaged wires or worse.

Looking at the layout of components, it occurred to me that a fairly simple change to the printed rear frame element offered a more elegant solution to the design. I decided to do this in a mechanical (subtractive) fashion, but it can also (and should) be done with a change to the CAD/STL file for this part. Perhaps the Prusa design team will see the merits of doing so.

After determining my plan, I ordered two of these pieces so that neither printer would be inoperative while I made the modification, only for the actual time it took to disassemble the frame and substitute the modified part. I mounted the part(s) in a small milling vise and milled a 1/4" (6.35mm) channel on the inside surface of the part as shown.

It runs from the motor mount boss, to the opposite end, with a small 45 degree "jag" toward the end so that it "exits" into the narrow "ramped" feature of the end. It only needs to be deep enough to accommodate the four-wire bundle, but no harm if it's deeper.

Now, during disassembly/replacement, unmount the Y-axis motor and rotate it 90 degrees so that the wire bundle exits toward the rear instead of downward. Reassemble everything with the wires going into the control board compartment now barely visible.

From underneath, the wires are now completely hidden, with nothing exposed or dandling to snag on anything. Looks more professional IMHO, and is extremely simple (for future units).