Under extrusion may caused by:

1) PTFE tube worn out
Replace PTFE tube will solve the problem, we suggest to replace both PTFE tube and nozzle together. As you may need to clean the internal of the heatsink and the heating block. You can purchase the related parts at our shop.

2) Clogged nozzle
Dust on filament, bad quality filament, printing different temperature filament may clog the nozzle. Replace nozzle will help.

3) Extruder arm broken
Extruder arm broken can cause the pressure lost on the extruder, pressure inconsistent will lead to under extrusion.

4) Filament thickness inconsistent
This is quite rare, unless you are using very bad quality filament.

5) Slicing setting issue
Check the flowrate on your slicing setting. Make sure the temperature are set according to the filament manufacturer suggested.

6) Extruder gear worn out
Replace one will help.

7) Extruder gear loose
Check and tighten the extruder grear will help.

8) U-slot bearing on the extruder stuck
If the bearing is having issue, replace the bearing may help.

9) Filament entangled 
Check the filament if there’s any entangled issue or some other issue that causing the flament can’t feed into the extruder smoothly.

10) Filament issue
Some filaments may need higher temperture, filament from different brand may need slight tweak on the printing profile. Different batch of the filament from same manufacturer may need slight tweak as well.

11) Moisture Filament
Some user feedback, moisture filament may need higher temperature as well.
Getting a filament dryer may help.

12) E-steps
Adjust proper E-Steps according to the filament and your printer.

 

Share with us how do you fix this issue in the comments.

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