[Prusa MK3.5(s)] Relative Extruder Temperature for Bed Leveling

[0uincy]

By default the printer heats up the bed to the defined first layer bed temperature and the nozzle to 170°C before bed leveling. This prevents blobs of filament from being deposited on the bed during leveling, but it increases total print times for higher temp materials like Polycarbonate and Nylon when the printer waits for the nozzle to heat up to it's first layer temperature (270~285°C) all the way from 170°C.

I've edited the start g-code to set the extruder temperature to be 50°C cooler than the first layer temperature for bed leveling which still prevents oozing during bed leveling for any material, but reduces the wait time for higher-temp materials:

 M104 T0 S{(first_layer_temperature[0] - 50)} ; set extruder temp for bed leveling
 M109 T0 R{(first_layer_temperature[0] - 50)} ; wait for temp

instead of:

 M104 T0 S170 ; set extruder temp for bed leveling
 M109 T0 R170 ; wait for temp