Every Maker Faces These Problems
By Inno Uncle
If you've been 3D printing for more than a week, you've seen at least three of these failures. The good news: they're all fixable with the right diagnosis. Let's tackle them one by one.
1. Stringing (Oozing)
Symptoms: Thin plastic hairs between towers, columns, or any non-continuous print areas.
Causes: Nozzle temperature too high, retraction settings off, or wet filament.
Fix:
- Reduce nozzle temperature by 5°C increments until strings disappear
- Increase retraction distance (Bowden: 4-7mm, Direct Drive: 0.5-2mm)
- Increase retraction speed to 40-60mm/s
- Enable "wipe" and "coast" in your slicer
- Dry your filament — wet filament strings no matter what
2. Warping (Lifting Corners)
Symptoms: Print corners lift off the bed, causing a curved bottom surface.
Causes: Uneven cooling, poor bed adhesion, or printing ABS/ASA without an enclosure.
Fix:
- Use a brim (5-10mm) on sharp corners
- Set bed temperature correctly: PLA 50-60°C, PETG 70-80°C, ABS 100-110°C
- Turn off cooling fan for first 3-5 layers
- Use a printer enclosure for ABS, ASA, and PC
- Clean your build plate with 99% isopropyl alcohol before every print
- Apply glue stick or hairspray for ABS on glass beds
3. Layer Shifting
Symptoms: Layers suddenly shift horizontally, creating a staircase effect.
Causes: Loose belts, overheating stepper drivers, collision during travel moves.
Fix:
- Tighten X and Y axis belts — they should twang like a guitar string
- Check grub screws on stepper motor pulleys — if loose, the motor spins but the belt doesn't move
- Reduce travel speed below 200mm/s if collisions occur
- Add "Z-hop" of 0.2-0.4mm during travel moves
- Ensure stepper driver current is set correctly in firmware
4. Under-Extrusion
Symptoms: Thin walls, gaps between perimeters, weak layers that break easily.
Causes: Clogged nozzle, extruder gear slipping, filament diameter inconsistency.
Fix:
- Cold pull (atomic pull) to clear nozzle clogs — heat to 230°C for PLA, push filament through, cool to 90°C, then yank it out
- Clean extruder gear teeth with a brush — plastic debris reduces grip
- Adjust extruder tension — too loose = slipping, too tight = filament grinding
- Check filament diameter — cheap filament can vary by +/-0.1mm, causing underextrusion
- For high-speed printers, upgrade to a high-flow nozzle — standard brass nozzles can't keep up above 300mm/s
5. Poor Bed Adhesion (First Layer Issues)
Symptoms: Print detaches mid-job, first layer has gaps or elephant's foot.
Causes: Nozzle too high/low, dirty bed, wrong bed temperature.
Fix:
- Level your bed manually first, then run auto bed leveling
- Adjust Z-offset — you want slight squish on the first layer (use the "paper test")
- Set first layer height to 0.2-0.3mm (taller = more forgiving)
- Clean the bed with dish soap and hot water, then IPA
- For PEI sheets: lightly scuff with 0000 steel wool to restore adhesion
- Upgrade to a PEI build plate — the single best adhesion upgrade for any printer
Pro tip: Print a first-layer calibration square (50x50mm, 0.2mm height) whenever you change filament brands. It takes 5 minutes and saves hours of failed prints.