I made a flexible-material multi-material identifier for standard non-copy ASSA keys. In order to print it, you must likely adjust your printer (see selectorII, filamentsensorII).
Size parameters are hard coded directly in the sketched "yttre form" and "inre hålrum" of the freecad source. Why not replace the penguin modifier by your favourite shape?
ninja tec, fillamentum NinjaFlex, Flex98
Use support, but set support material->auto-generate support material = OFF for the object (in slic3r). Then, use the included support enforcer for the object (double click, add...)
Use 200m3 wipe.
Also, please load and position the Wipe-tower support at the wipe tower (see image) in order to make the first material wipe to work better.
Print speed should be <30mm, Do not forget to loosen the idler pressure as much as possible,
To successfully make MMU-prints with flexible materials, I suggest some mods of the original prusa printer:
print time: 0.2mm 53min