Extrusion factors?



  • what exactly is extrusion factors? what are the components involved in extrusion factors?
    also how to set the extrusion factor to the slicer, example simplify3D?



  • The extruder wheel is moving according to the steps/mm setting in your config file. This number tells the controller how to convert the desired linear filament motion towards the nozzle into the appropriate rotary motion of the wheel feeding the filament.

    You can see it as a percentual value of the normal extrusion amount if you move the decimal point two positions to the right.

    Consider the command

    [[language]]
    G1 E1
    
    ```It instructs the machine to feed 1 mm of raw filament into the nozzle. Now, depending on how the extrusion factor is set it will affect how much filament actually is pushed through the nozzle.
    
    100% (1.00) is "normal". Extruder will push 1mm through the nozzle.
    105% (1.05) is pushing 5% MORE filament
    95% (0.95) is pushing 5% LESS filament


  • so i can modify the extruder steps per mm relating to the extrusion factors?


  • administrators

    @pao_wikhan:

    so i can modify the extruder steps per mm relating to the extrusion factors?

    Yes you can. However, in my experience every filament has its own ideal extrusion factor. So I leave the extruder steps/mm set at the calibrated value. When I start a new roll of filament I do a small test print and adjust the extrusion factor to get good top infill. Then I always set that extrusion factor in DWC or PanelDue when printing with that roll.



  • @dc42:

    @pao_wikhan:

    so i can modify the extruder steps per mm relating to the extrusion factors?

    Yes you can. However, in my experience every filament has its own ideal extrusion factor. So I leave the extruder steps/mm set at the calibrated value. When I start a new roll of filament I do a small test print and adjust the extrusion factor to get good top infill. Then I always set that extrusion factor in DWC or PanelDue when printing with that roll.

    can i do a macro for it? like enable it before printing?


  • administrators

    Yes, just include a call to that macro in your slicer start gcode.



  • oh thats possible?
    can you give a sample of the "call to macro" on slicer? first time i heard that.



  • In your slicer, especially if you use slic3r you can save profiles so I have "large kossel ngen" as a filament profile, there is a setting for extrusion multiplier. You set that as David said, by experimenting with it whilst printing. Next time you slice something for that filament you just chose that profile. You could write the multiplier (which is the "flow/extruder" on panel due or DWC) on the reel.

    It's important though to set your initial steps/mm experimentally with a known filament. So let's say you use colorfabb white pla, and get the extruder nicely setup ie the exact steps/mm, keep 10 meters of it. Now if you change your setup recalibrate with that known filament. Now your extrusion multiplier that relates to your other filaments will still work.

    Some filaments are thicker or thinner, and some are soft so the drive gear in the extruder bites into it more or less.



  • yes, but after setting those things up. i believe what David said is to call a macro depending to what the extrusion factor is. i believe its best to set it on the hardware level than having multiple slicer profiles for a type of filament.

    is it?

    [[language]]
    M98: Call Macro/Subprogram
    Parameters
    Pnnn Macro filename
    Example
    M98 Pmymacro.g
    Runs the macro in the file mymacro.g. Macro calls can be nested (ie a macro can call another macro).
    
    The filename to include a path to a subdirectory. For relative paths, the default folder is /sys, but some implementations may check the /macros directory too. Absolute file paths are also supported starting with "0" for the internal SD card or "1" for the external SD card if fitted.
    
    M99: Return from Macro/Subprogram
    Example
    M99
    Returns from an M98 call, this is not required to return from the end of a macro and the macro naturally returns at the end of file.
    
    RepRapFirmware closes the currently active macro file. If a nested macro is being run, RepRapFirmware goes up one stack level.
    
    


  • Depends where you want to activate it from? And whether you remember to do it. If I specify the filament in slic3r and slice it, I can then upload and print. All done.

    Honestly I usually tweak it as the first layer prints +/- 1-2%. This used to be impossible as first layer heights could be variable. Now with piezo/strain effector systems they are always incredibly precise, so I know if my first layer is a bit thick with filament my extrusion multiplier needs to be tweaked down a bit and vice versa.

    What is the gcode for set extrusion multiplier anyway?



  • What is the gcode for set extrusion multiplier anyway?

    M221



  • Thanks, that's useful.


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