Collection of Post-Processor Scripts for Prusa GCode

This script searches through GCODE files generate for the Prusa MMU and locates any temperature changes that occur between filament changes. It then moves these temperature commands after any cooling moves take place.

Background

The default operation in Prusa Slicer (as of version 2.0.0) performs the temperature change before any cooling moves take place. This causes issues as the hotend will heat up or cool down while the previous filament is still in the chamber. My fix for this is to edit the GCODE to request the temperature change after all cooling moves just before the current filament is extracted from the hot end. Ususally there is still plenty of time to get the hotend to the desired temperature (or very close) by the time the MMU loads the next filament to the hotend.

Details

The script look for any M104 commands that occur immediately after a retract (G1 E-.....). It then moves the M104 command to right after the G4 command that is the configured delay to wait before unloading (usually 0).

Therefore this:

G1 E-15.0000 F6000
G1 E-24.5000 F1200
G1 E-7.0000 F600
G1 E-3.5000 F360
M104 S200 ;TEMP CHANGE
G1 Y144.940 ;START OF COOLING MOVES
G1 X229.250 E20.0000 F488
G1 X178.820 E-20.0000 F434
G1 X229.250 E20.0000 F380
G1 X178.820 E-20.0000 F326
G1 E-35.0000 F2000
G1 Y144.800 F2400
G4 S0 ;DELAY 0s
T4 ;CHANGE TO EXTRUDER #4

Would become:

G1 E-15.0000 F6000
G1 E-24.5000 F1200
G1 E-7.0000 F600
G1 E-3.5000 F360
G1 Y144.940 ;START OF COOLING MOVES
G1 X229.250 E20.0000 F488
G1 X178.820 E-20.0000 F434
G1 X229.250 E20.0000 F380
G1 X178.820 E-20.0000 F326
G1 E-35.0000 F2000
G1 Y144.800 F2400
G4 S0 ;DELAY 0s
M104 S200 ;TEMP CHANGE
T4 ;CHANGE TO EXTRUDER #4