Extrusion multiplier calibration

Updated 2 months ago ​by Mikolas

The Extrusion multiplier setting allows the fine tuning of the extrusion flow rate - simply described as how much filament comes out of the nozzle. Without calibration, two scenarios can happen.

If the flow is too high it can cause a filament overflow as there is just too much material being extruded and no more space between perimeters where the material could go to. If the flow is too low, there will be gaps between perimeters and the mechanical properties of the model will be compromised.

 It is given as a factor, e.g. 1 means 100%, 1.05 would mean 105%.

Calibrate extrusion multiplier using our pre-made GCODE

  1. Download Extrusion calibration GCODE (for Original Prusa i3 MK3)
  2. Upload it to SD card and print it with PLA
  3. Make three or more measurements of each wall and calculate the overall average thickness
  4. Extrusion multiplier = (0.45Average measured wall thickness)
  5. Change the Extrusion multiplier in Filament Settings - Filament
It's difficult to make accurate measurements of a single perimeter wall with cheap digital calipers. Make multiple measurements and watch whether most of them are higher or lower compared to the value set in Slic3r.  
Calculated extrusion multiplier is only relevant for a specific spool manufacturer and sometimes it can even differ between different color variants of the same filament.

How to calibrate extrusion multiplier with user-generated GCODE

  1. Make sure to check that you extrusion multiplier is set to 1.0 if not then change it (Filament Settings - Filament - Extrusion multiplier)
  2. Print a cube (eg. 40x40x40 mm) using the vase mode (Calibration cube STL)
    1. You can find the vase mode under Print settings - Layers and perimeters - Vertical shells - Spiral vase
  3. Make three or more measurements of each wall and calculate the overall average thickness
  4. In Slic3r go to Print settings - Advanced, here you can see the External perimeters width
  5. Extrusion multiplier = (External perimeters widthAverage measured wall thickness)
  6. Change the Extrusion multiplier in Filament Settings - Filament

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