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Zeke
 Zeke
(@zeke)
Active Member
Extrusion multiplier

No matter what value I put in PrusaSlicer's extrusion multiplier field, the gcode always outputs M221 S95 for the flowrate of the print. Why doesn't it output what I enter in the field?

Posted : 28/03/2021 10:36 pm
bobstro
(@bobstro)
Illustrious Member
RE: Extrusion multiplier

The M221 is (annoyingly) added by the default start gcode. The slicer extrusion multiplier setting is used throughout the gcode generation. They operate independently. I don't like the gcode "tweak" so comment it out of my start gcode. 

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 28/03/2021 11:00 pm
Zeke
 Zeke
(@zeke)
Active Member
Topic starter answered:
RE: Extrusion multiplier
Posted by: @bobstro

The slicer extrusion multiplier setting is used throughout the gcode generation.

So, it doesn't matter if the M221 is in the gcode, because the E values are adjusted for the multiplier?

Posted : 28/03/2021 11:10 pm
bobstro
(@bobstro)
Illustrious Member
RE: Extrusion multiplier
Posted by: @zeke

So, it doesn't matter if the M221 is in the gcode, because the E values are adjusted for the multiplier?

Sorry, I wasn't clear. They are independent. Changing one won't change the other. They are, howrver, combined when you print. If you specify a 0.9 extrusion multiplier in the slicer, the gcode will reflect less filament.

If you then print with a 0.95 M221 adjustment either on the printer tune menu or in gcode, you'll get a 0.855 reduction in filament flow.

If you reset the M221 flow, the same gcode will print with a 0.9 flow as expected.

 

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 28/03/2021 11:39 pm
Zeke
 Zeke
(@zeke)
Active Member
Topic starter answered:
RE: Extrusion multiplier

@bobstro

Okay, then if I replace this line in my start gcode:

M221 S{if layer_height<0.075}100{else}95{endif}

With this:

M221 S100

Then my code will always match the value in my multiplier?

Or should I just comment out the entire line?

Posted : 29/03/2021 12:08 am
Neophyl
(@neophyl)
Illustrious Member
RE: Extrusion multiplier

They are 2 separate things, Extrusion multiplier is used to compensate/change the amount of plastic the slicer calculates is needed.
Flow will ALSO effect the amount of plastic extruded but can be set either via the start gcode OR via the printers menu.  Setting the flow either in the start gcode or on the printers LCD will NOT effect the extrusion multiplier.  Their effects do combine though so if you set both lower than 1 then you will have a much more lower than 1 amount of plastic.

 

Posted : 29/03/2021 10:26 am
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