Motor Visualiser No Glue

I looked around on Printables and Thingyverse for simple motor visualiser to put on the Idler motor for my MMU2, so I could tell if the motor was still rotating even if the idler was not.  I needed to put to bed the endless helpful suggestion “you need to further tighten the 2 idler shaft connection screws suggestion", once and for all.   

Most designs had issues, they needed to be glued, depending on magnet thickness would rub on motor and not turn, were too large, too ornate, didn't fit my magnets.  Whatever … all too hard just make my own to suit what I had.  

I had some small magnets 3mm radius and 2.7mm high lying around, so I designed something around those so I could get something working ASAP.

Your magnets may differ in size … so I have included the SCAD file.  You can change a few parameters (id and height) and quickly get the design that suits your needs.  

It needs the OpenSCAD PolyRound library.  Best lib eva.

I used a 0.4mm nozzle with some horrible old generic PETG at 0.15 layer height and 15% infill.

Good luck with wrestling your MMU2 to try and make the damn thing work consistently!  

For mine it turned out the screws DIDN'T need tightening further, the idler was built well and was buttery smooth in it's complete rotation, and nothing was jamming it … literally ticking off all the Prusa FAQ suggestions.

It turned out the motor was stalling, and I needed to use the Tune menu in the VERY latest firmware to set the sensitivity from 4 to 7, as well as have the spring screws set to 0.5mm below the chassis.  

I am installing the MMU2 on a MK2.5S (12V) so maybe that's related to needing more power, but it seems lots of MK3 owners have similar issues.