MMU2 minimum color purge calibration tool

thingiverse

**Update 9/2/19**: I updated a taller version that's easier to read but requires more setup initially. I added a .3mf file to get you started, which prints at 0.5 layer using a 0.4 nozzle. It works well. I highly recommend this version. Check below for how to use it. I also added a 5-color G-code for an easy option. --- This calibration tool captures every permutation of color transition from 2 to 5 filaments in one object. Print this to determine how much bleed is occurring beyond minimum purge and read the results off the print to set the correct purge volumes. I tried to use the smallest amount of filament possible, including a wipe tower, which totals about 50 mm^3. Once you decide on the last bend, add another +5 for margin. Here's what I found: | | unloaded | loaded | |---|---|---| | blue | 40 | 70 | | green | 15 | 70 | | orange | 10 | 70 | Compare these to stock values of all 70, 70. If you find a large discrepancy, you can switch to advanced purging volumes and enter each individually. For example, if blue->green only, say, +15, I wouldn't want to waste so much setting to +40 and I'd change advanced: from =15, to =50. If you want, you can print a second to confirm and it should be clean. For the careful observers, in the example below, you will see I mistakenly cut one layer short; it should have had 7 layers. Still works, but top blue layer of block A has no reference above. I added pictures at bottom of tall version, showing that it is easier to see the color pollution and find the transition. Anyone else see the optical illusion of the photo below, where it looks crooked?