Troubleshooting Under-Extrusion on the Kobra 3

Under-extrusion — not enough filament coming out — shows up as gaps, weak layers, and rough surfaces. It has many causes. Work through this list in order.

Visual Symptoms

• Gaps in top surface or between perimeters
• Weak infill that breaks easily
• Layer lines with visible gaps
• Strands that break mid-air on overhangs

Diagnosis Checklist (in order)

1. Wet Filament

Most common cause people miss. Dry your filament first (see drying guide) before chasing any other cause.

2. Temperature Too Low

Check your temperature tower results. Try printing 5°C hotter.

3. Print Speed Too Fast

Reduce speed by 20%. If under-extrusion disappears, you were pushing the material faster than it could melt.

4. Partial Clog

Manually extrude 100 mm at 2 mm/s from the LCD. Watch the extruder gear — if it's skipping, you have a partial clog.

5. Extruder Tension

Check the extruder gear grip on the filament. Examine filament coming out of the extruder — if it has grinding marks or looks chewed, tension is too high or the gear is worn.

6. Flow Rate Too Low

In Orca Slicer, check filament flow rate. Should be 0.95–1.05. Run flow calibration if not done recently.

7. Bowden Tube / PTFE Liner

Check for gaps at the PTFE liner-to-nozzle junction. A gap here causes filament to jam. Remove the nozzle and inspect.

Fixes by Cause