Under-extrusion

Under-extrusion is the opposite of over-extrusion: the printer is not pushing out enough plastic. This results in brittle prints with gaps, missing layers, or a spongy texture.

Common Symptoms

• There are visible gaps between the lines of each layer.
• Layers do not bond well to each other, and the part breaks easily.
• Entire layers are missing in certain parts of the print.
• The print looks fragile, rough, or stringy.

Causes and Solutions

1. Clogged Nozzle !!! warning "Most Common Cause" A partially or fully clogged nozzle is the number one cause of under-extrusion. * Solution: Follow the "Cleaning the Nozzle" guide. Use the cleaning needle to clear the obstruction. If the problem persists, you may need to perform a "Cold Pull" or replace the nozzle.

        

   Illustration showing the result of a "Cold Pull": the tip of the removed filament has the exact shape of the nozzle's interior, pulling debris out with it.

2. Dirty Extruder Drive Gear

   • Cause: Plastic debris can build up in the teeth of the gear that pushes the filament, causing it to slip.
   • Solution: Follow the "Cleaning the Extruder (Drive Gear)" guide and use a brush to clean the gear's teeth.

3. Calibrate the Flow Rate

   • Cause: The flow rate value may be set too low.
   • Solution: In the printer's menu, go to Tune -> Flow and increase the value (e.g., from 95% to 100%). For a permanent fix, adjust it in your slicing software.

4. Printing Temperature Too Low

   • Cause: If the nozzle temperature is too low for the material, the plastic becomes too viscous and difficult to extrude.
   • Solution: Increase the printing temperature in 5°C increments.

5. Under-extrusion on the First Layer

   • Cause: If the problem only occurs on the first layer, the cause is a nozzle that is too far from the bed.
   • Solution: Adjust your "Live Adjust Z" to a more negative value.

   

Illustration of a print with gaps and missing layers due to under-extrusion.