[ALREADY ADDED]Preheat bed and extruders in parallel

[ctacke]

Currently the G-code generated is serially preheating the bed and extruders. Since I'm impatient and it saves a little time, I'd prefer them to get heated in parallel.

Right now the slicer outputs something like this (I added comments):

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M140 S60 ; set bed temp
M190 S60 ; wait for bed to heat
M104 S190 T0 ; set extruder temp
M109 S190 T0 ; wait for extruder to heat

It would be an improvement (and likely easy to implement) something like this:

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M140 S60 ; set bed temp
M104 S190 T0 ; set extruder temp
M190 S60 ; wait for bed to heat
M109 S190 T0 ; wait for extruder to heat

[S3D-Jake]

To preheat in parallel, you can use then starting script in combination with the heating variables. The presence of the heating variables will cause the automatic heating commands that you're currently seeing to not be generated.

starting script example for single extruder g-code machine:

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M140 S[bed0_temperature] ; set bed temp
M104 S[extruder0_temperature] T0 ; set extruder temp
M190 S[bed0_temperature] ; wait for bed to heat
M109 S[extruder0_temperature] T0 ; wait for extruder to heat

[kburgoyne]

I came looking to suggest a similar feature, then found this reply intead.

My recommendation is to preheat the extruder to only bed temp in parallel with the bed heating. On my printer the extruder will heat faster than the bed, and being at full extrude temp while waiting for the bed to finish heating can cause the extruder to drool.

Since the bed should never be at full extrude temp, using its temp as a limit for preheating the extruder in parallel with the bed should safely avoid drooling while waiting on the bed to reach temp.

Note the code doesn't wait for the extruder to reach bed temp before setting the extruder to extrude temp. It only waits for the bed to reach temp.

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M140 S[bed0_temperature] ; set bed temp
M104 S[bed0_temperature] T0 ; set extruder to preheat to bed temp in parallel
M190 S[bed0_temperature] ; wait for bed to heat
M104 S[extruder0_temperature] T0 ; set extruder temp to final
M109 S[extruder0_temperature] T0 ; wait for extruder to heat