Posts: 140
Joined: Sun Jul 19, 2015 9:05 am

M106 appears before start script

Wed Jun 23, 2021 4:38 am

Have cooling set to 0 on Layer 1.

Also have set max cooling of 40% for layer times <15secs.

Seems odd that in the Gcode there's a "M106 S102" (to set cooling to 40%) BEFORE the start script.

That means the parts fan is running at 40% whilst the hotend is trying to heat up. Not cool. Or rather, too cool.

On top of that, since the fan has explicitly been set to 0 for layer 1 (important for probably any filament, not least ABS), well the 15sec rule should probably not over-ride that either, and kick in on Layer 2 instead. But either way we don't want the parts fan before the start script!

(gcode attached + factory file... it's the last process in the list Kliipper ABS test)
(63.53 KiB) Downloaded 10 times
3mm - 45 degree fixture.gcode
(1.07 MiB) Downloaded 10 times

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Posts: 2347
Joined: Tue Mar 10, 2015 4:09 pm

Re: M106 appears before start script

Wed Jun 23, 2021 6:01 am

As you quite rightly say, the 15 second fan override is being implemented for the first layer.....i.e. the software is "doing what is says on the tin" and overriding the fan speed if the time to print the layer.....any less than 15 seconds.

The best I can offer is to suggest you use the Variable Settings wizard to create a separate profile just for the first layer that doesn't have the override applied.

I do take the point that the override for the first layer is being invoked before the start script is executed.......but I'm sure someone else will post a reason for this being so.
Doug Kightley
Volunteer at the National Tramway Museum
Railway modeller and webmaster at

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