Correct purge temperature when printing with different temperature materials

[amatulic]

What happened?

When current filament is being retracted and cool down is being performed, the next filament temperature is set immediately, potentially causing a jammed nozzle if the next filament requires a lower temperature than the filament still in the nozzle.

The nozzle must be purged at the higher of the two temperatures.

Project file & How to reproduce

Just make a project with filaments with different temperature settings, for example a PLA part with PETG supports.

Observe that when switching from PETG (high temperature) to PLA (lower temperature) the low temperature is set before the PETG is purged from the nozzle, causing the nozzle to jam because it is too cool to purge the PETG.

I have fixed this issue!

The fix is in a PrusaSlicer pull request here: prusa3d#9737

I thought it would be helpful to users of this fork, which I believe is intended for multi-material printing.

Version

No response

Operating system

Any

Printer model

Prusa MK3S + MMU2S

[rvmn]

that is smart, is going in the next version for sure! (due in about two weeks, end of april).
thanks a bunch!!!

[amatulic]

You're welcome, and I hope this gets into PrusaSlicer soon too.

I just edited the issue description for better clarity. I can't believe I wrote that rambling mess earlier.