6 common 3D print quality problems and how to fix them

First layer not sticking, warping, stringing, layer splitting — practical fixes that actually work.

2026-01-25 · 3DHub.ge

Most failed prints come down to a handful of causes. Here is how to recognise and fix them.

1. First layer will not stick

The most common problem by far. Causes:

• Nozzle too high. Lower the Z-offset — the first layer should be slightly squished, not just laid down.
• Dirty bed. Even finger grease prevents adhesion. Clean it with isopropyl alcohol.
• Bed too cold. PLA — 60°C, PETG — 80°C.

2. Corners lifting (warping)

The plastic cools, contracts, and pulls the corners up. Fixes: raise bed temperature, disable cooling for the first layers, add a brim. For ABS an enclosure and protection from draughts are essential.

3. Stringing between parts

Material oozes from the nozzle during travel moves. Fixes: increase retraction distance, drop the temperature by 5–10°C, and dry your filament — moisture is the most common culprit.

4. Layers separating

The part splits along layer lines. This is weak layer adhesion: temperature too low or cooling too aggressive. Raise the temperature 5–10°C and reduce fan speed (especially for PETG and ABS).

5. Layer shift mid-print

A loose belt, or the nozzle collided with the print. Check belt tension, lower the speed, and enable Z-hop.

6. Gaps and holes in the surface

Under-extrusion. Check for a partially clogged nozzle, confirm flow rate is at 100%, and make sure the extruder gear is not slipping.

The golden rule

Change one setting at a time, then print a test model. If you change five things at once, you will never know which one worked.

Frequently asked questions

Why is my first layer not sticking?

Three main causes: the nozzle is too high (lower the Z-offset), the bed is dirty (clean with isopropyl alcohol), or the bed is too cold (PLA — 60°C, PETG — 80°C).

How do I dry filament?

Use a filament dryer or an oven at low heat: PLA — 45–50°C for 4–6 hours, PETG — 60–65°C for 4–6 hours. Wet filament causes stringing and weak, cracking layers.