Start G-Code to preheat 2nd extruder

[evilC 0]

I have just got my first IDEX printer (Snapmaker J1)

 

The Cura profile which comes with it does not start heating T1 until both T0 and the bed have heated up

Here is their start g-code:

;--- Start G-code Begin ---
M104 S{material_print_temperature_layer_0} ;Set Hotend Temperature
M140 S{material_bed_temperature_layer_0} ;Set Bed Temperature
G28 ;Home
G1 Z0.8
M109 S{material_print_temperature_layer_0}
M190 S{material_bed_temperature_layer_0}
G1 Z0.8 F6000
M201 X10000 Y10000 Z500 E5000
M593 P1 F50
M205 V5
G92 E0
G1 F200 E2
G92 E0
;--- Start G-code End ---

 

If I change it to this:

;--- Start G-code Begin ---
M104 S{material_print_temperature_layer_0} ;Set Hotend Temperature
M140 S{material_bed_temperature_layer_0} ;Set Bed Temperature
; >>> MODIFIED CODE START
M104 S{material_standby_temperature, 1} T1 ; Start heating T1
; >>> MODIFIED CODE END
G28 ;Home
G1 Z0.8
M109 S{material_print_temperature_layer_0}
M190 S{material_bed_temperature_layer_0}
G1 Z0.8 F6000
M201 X10000 Y10000 Z500 E5000
M593 P1 F50
M205 V5
G92 E0
G1 F200 E2
G92 E0
;--- Start G-code End ---

then this seems to do the trick, but there's a problem:

If I do a single extruder print, and uncheck "Enabled" for the 2nd extruder, like so:

Then the generated G-Code still heats the 2nd extruder, even though it is not used for the print. Is there a way to somehow generate conditional G-Code, or is there some equivalent of {material_standby_temperature, 1} which would return 0 if the 2nd extruder is not used?

Edited December 13, 2022 by evilC

[GregValiant 1,141]

Yes, that happens because the second material isn't affected by disabling the extruder.  It still has a set "standby temperature" and that is what you are asking for in the StartUp gcode.

 

Before you disable the extruder - set the "Material | Standby Temperature" of that extruder to 0.  The downside is you must remember to change it back, OR, re-select that settings profile and "discard" the changes.  That would also change it back.  With the Standby Temperature at 0 the code comes out as you would want with:

M104 S0 T1 ; Start heating T1

You may also run into a problem if you disable Extruder0, or start a print with Extruder1.  Your startup gcode explicitly asks for T1 to start out at Standby Temperature and T0 to start at Print Temperature.  That may not always be true. You'll need to stay aware of that.

A fix may to consider is adding additional printers in Cura.  Each could have it's own startup gcode.  I have a second Ender installed as my "TPU Printer" because the purge lines in the StartUp gcode are a lot slower than for PLA or PETG.

 

I'm not familiar with the Snapmaker printers, but some IDEX printers have gcode commands that tell the printer what Mode to use.  Raise3D uses something like M650 for regular, M651 for Mirror, and M652 for Duplicate.  In that case you would install 3 printers and use the one for the Mode you want to print with and the M65_ command would be in the StartUp Gcode.

Edited December 14, 2022 by GregValiant

[evilC 0]

Yeah I already have an Ender 3 modded with linear rails and a Hemera, and have both added in Cura and running off one Octopi

Being a bedslinger tho, the Ender3 does not compare to the new CoreXY IDEX. I have souped the Ender 3 speeds up to the max (100mm/s, 3000 accel), but this new one will do 200mm/s, 6000 accel out of the box without any tweaks. Plus of course it's an IDEX, so I can use Copy Mode to print off two copies at once, making it basically 4x as fast as the Ender3

 

Quote

I'm not familiar with the Snapmaker printers, but some IDEX printers have gcode commands that tell the printer what Mode to use.  Raise3D uses something like M650 for regular, M651 for Mirror, and M652 for Duplicate

My printer does not support those AFAIK. Besides, this preheat issue mainly concerns "Normal" IDEX mode (Multi-material in one print)

 

I put in a feature request on the GitHub repo, let's see what the devs think...