- Signs of underextrusion include gaps between lines in solid layers, and lines with a measured line width that is smaller than the value set in the slicer.
- Signs of overextrusion include ridges between lines in solid layers, and lines with a measured line width that is larger than the value set in the slicer.
Adjusting the Extrusion Rate:
- Go to the Scripts tab in the Advanced Settings in Simplify3D. For other slicers, navigate to the starting script.
- In the Starting Script subtab, find the M92 E## gcode line. The number after the E controls how many steps per mm that the motor turns (the mm is a holdover from filament printing, and doesn't translate to a physical representation for pellet printing). For most pellets, this value should be 55 for the most recent configuration of Gigabot X. For more information on this gcode command, see the Marlin documentation here.
- Increase that calibration number to address underextrusion, and decrease the number to address overextrusion.
Calibrating the M92 E value:
- Print a model with 1 perimeter, no top layers, and no infill. At re:3D, we use a cylinder. The relevant settings in Simplify3D are shown below:
- Use a pair of calipers to measure the perimeter width at the top layer.
- Compare the measured value to the expected extrusion width in the slicer:
- Adjust the M92 E value accordingly, assuming a linear relationship between the E value and the layer width.
- Repeat until the measured layer width is within 0.1mm tolerance of the expected value.
Alternative Setting: Extrusion Multiplier
Alternatively, adjusting the Extrusion Multiplier setting has the same effect as adjusting the M92 E value. The difference is in how they're typically used: the M92 E value calibration is usually treated as a baseline, and the Extrusion Multiplier is treated as a deviation from a baseline. Choose whichever setting makes the most sense for your application.