preheating for print suggestion? (thoughts on giving the bed a head start)
MK3/s && mk3s+
When the printer already has filament loaded into it (detectable via sensor), and a print has been selected to print from the SD card.. Can it preheat ONLY the bed for a little bit before starting the preheating of the nozzle? The lead time could be calculated after the thermal calibration test that's required in the latest firmware. This would prevent the current situation of the nozzle getting to temp well before the bed and it just oozing filament out. Sometimes (even with the prusa PLA filament) it will leak out so much (waiting for the bed temp) that the prime extrusion at the beginning of the print will be empty and the perimeter is actually what primes the nozzle.
RE:
Easy to fix by adjusting your startup gcode in Prusaslicer. You can set the nozzle temperature to 170 while heating up and going through mesh bed leveling (the Mini has this built-in).
As an example, see https://projects.ttlexceeded.com/3dprinting_prusaslicer_start_gcode_mk3.html. It's a bit dated by now but variations of this code are used by many, including myself, to prevent oozing. I modified it to go to 40 degrees less than my first layer temperature, instead of a fixed temperature.
RE: preheating for print suggestion? (thoughts on giving the bed a head start)
I usually hit preheat through the Prusa menu when I start the printer. It gets things warmed up and ready to go, but I like @fuchsr's idea even more.
Aaron
RE: preheating for print suggestion? (thoughts on giving the bed a head start)
Any chance we could have the startup GCode that does this?? Would be very handy and should really be a standard feature!
RE: preheating for print suggestion? (thoughts on giving the bed a head start)
It is all on the site linked to above. All annotated with explanations.
RE: preheating for print suggestion? (thoughts on giving the bed a head start)
Here's my current startup code:
; PrusaSlicer start gcode for Prusa i3 Mk3S
; Last updated 20230201 - RF - Adopted from Bob George
M862.3 P "[printer_model]" ; printer model check
M862.1 P[nozzle_diameter] ; nozzle diameter check
M115 U3.11.0 ; tell printer latest fw version
; Set coordinate modes
G90 ; use absolute coordinates
M83 ; extruder relative mode
; Reset speed and extrusion rates
M200 D0 ; disable volumetric e
M220 S100 ; reset speed
; Set initial warmup temps
M104 S{first_layer_temperature[0] - 40}; set extruder temp to 40 lower than print temp to prevent oozing
M140 S[first_layer_bed_temperature] ; set bed temp
M109 S{first_layer_temperature[0] - 40} ; wait for extruder no-ooze warmup temp before mesh bed leveling
G28 W ; home all without mesh bed level
G80 ; mesh bed leveling
; Final warmup routine
G0 Z80; Raise nozzle to avoid denting bed while nozzle heats
M140 S[first_layer_bed_temperature] ; set bed final temp
M104 S[first_layer_temperature] ; set extruder final temp
M109 S[first_layer_temperature] ; wait for extruder final temp
M190 S[first_layer_bed_temperature] ; wait for bed final temp
; Prime line
G0 Z0.15 ; Restore nozzle position - (thanks tim.m30)
G92 E0.0 ; reset extrusion distance
G1 Y-3.0 F1000.0 ; go outside print area
G1 E2 F1000 ; de-retract and push ooze
G1 X20.0 E6 F1000.0 ; fat 20mm intro line @ 0.30
G1 X60.0 E3.2 F1000.0 ; thin +40mm intro line @ 0.08
G1 X100.0 E6 F1000.0 ; fat +40mm intro line @ 0.15
G1 E-0.8 F3000; retract to avoid stringing
G1 X99.5 E0 F1000.0 ; -0.5mm wipe action to avoid string
G1 X110.0 E0 F1000.0 ; +10mm wipe action
G1 E0.6 F1500; de-retract
G92 E0.0 ; reset extrusion distance
; end mods
RE: preheating for print suggestion? (thoughts on giving the bed a head start)
Can I just replace my start code with yours, or is it specific for your setup?
My current start code is pretty much default - no good with coding so I've never touched it....
M862.3 P "[printer_model]" ; printer model check
M862.1 P[nozzle_diameter] ; nozzle diameter check
M115 U3.11.0 ; tell printer latest fw version
G90 ; use absolute coordinates
M83 ; extruder relative mode
M104 S[first_layer_temperature] ; set extruder temp
M140 S[first_layer_bed_temperature] ; set bed temp
M190 S[first_layer_bed_temperature] ; wait for bed temp
M109 S[first_layer_temperature] ; wait for extruder temp
G28 W ; home all without mesh bed level
G80 ; mesh bed leveling
{if filament_settings_id[initial_tool]=~/.*Prusament PA11.*/}
G1 Z0.3 F720
G1 Y-3 F1000 ; go outside print area
G92 E0
G1 X60 E9 F1000 ; intro line
G1 X100 E9 F1000 ; intro line
{else}
G1 Z0.2 F720
G1 Y-3 F1000 ; go outside print area
G92 E0
G1 X60 E9 F1000 ; intro line
G1 X100 E12.5 F1000 ; intro line
{endif}
G92 E0
M221 S{if layer_height<0.075}100{else}95{endif}
; Don't change E values below. Excessive value can damage the printer.
{if print_settings_id=~/.*(DETAIL @MK3|QUALITY @MK3).*/}M907 E430 ; set extruder motor current{endif}
{if print_settings_id=~/.*(SPEED @MK3|DRAFT @MK3).*/}M907 E538 ; set extruder motor current{endif}
RE: preheating for print suggestion? (thoughts on giving the bed a head start)
There's nothing unusual about my setup short of using Dragon hotends to facilitate nozzle swaps, but they didn't require any adjustments to startup gcode.
So you should be fine just copying and pasting.
One may reasonably argue about my dropping
M221 S{if layer_height<0.075}100{else}95{endif}
; Don't change E values below. Excessive value can damage the printer.
{if print_settings_id=~/.*(DETAIL @MK3|QUALITY @MK3).*/}M907 E430 ; set extruder motor current{endif}
{if print_settings_id=~/.*(SPEED @MK3|DRAFT @MK3).*/}M907 E538 ; set extruder motor current{endif}
but I prefer to have my flow rate at 100% and adjust the extrusion multiplier in filament settings if needed, and I haven't seen any effect from not setting the extruder motor current. But then again, if you want to keep those lines in, it won't do any harm.