Filament contracts as it cools. If different parts of the print cool at different rates — or if the first layer didn't adhere firmly enough — the contraction force is strong enough to pull the print off the bed surface. Warping is most common with ABS, ASA, and large flat prints in PLA.

• Increase bed temperature by 5°C increments until warping stops
• Clean the bed with IPA before every print — finger oils significantly reduce adhesion
• Add a brim (3–8mm) in the slicer to increase the contact area around the base of the print
• Check Z-offset — if the first layer isn't firmly pressed into the bed surface, adhesion is poor
• For ABS and ASA: an enclosure is mandatory — open-air printing of these materials produces warping on almost every print

Stringing occurs when liquid filament oozes from the nozzle during travel moves — when the print head moves from one area to another without extruding. The fix involves either pulling the filament back faster (retraction) or reducing the temperature so the filament is less liquid during travel.

• Increase retraction distance by 0.5mm increments (direct drive: 1–3mm, Bowden: 4–7mm)
• Increase retraction speed — faster retraction pulls filament back more cleanly
• Reduce nozzle temperature by 5°C increments — lower temperature means less oozing
• Enable combing in the slicer — routes travel moves over the print surface to keep strings inside the model
• Enable Z-hop — lifts the nozzle slightly during travel to avoid catching on existing print features

Under-extrusion means the printer is not delivering enough filament. The extruder is either slipping on the filament, the nozzle is partially clogged and restricting flow, or the print speed is too high for the filament to melt and flow fast enough.

• Check for a partial nozzle clog — perform a cold pull by heating to 200°C, then cooling to 90°C, and pulling the filament out sharply to remove debris
• Increase nozzle temperature by 5°C — higher temperature improves melt flow rate
• Reduce print speed — give the nozzle more time to melt filament at each point
• Increase flow rate in the slicer by 2–3% increments
• Check the extruder arm spring tension — a loose extruder grip causes filament slippage and inconsistent feed

Layer shifting means the print head moved to the wrong position at some point during the print. The cause is almost always mechanical: a belt that's too loose, a pulley that's slipping on a motor shaft, or the printer attempting to move faster than the motors can keep up.

• Check and tighten both X and Y axis belts — they should be taut when plucked
• Inspect all pulleys and confirm the grub screws on each are tightened against the motor shaft flat
• Reduce print speed — layer shifting at high speed is a motor current or acceleration issue
• Reduce acceleration values in the slicer or printer settings
• Confirm no physical obstruction is blocking the print head's movement range

Elephant's foot is caused by the first layers being over-compressed — the nozzle is too close to the bed, squishing the filament outward. High bed temperature can also keep the first layers soft long enough for them to spread under the weight of subsequent layers.

• Increase Z-offset slightly — raise the nozzle a small amount away from the bed surface
• Reduce bed temperature by 5°C — less heat means the first layers solidify faster
• Enable "elephant foot compensation" in Cura or the equivalent in your slicer

Each layer must be hot enough when the next layer is deposited to bond correctly. If the nozzle temperature is too low, or print speed too high, each layer cools before the next bonds to it.

• Increase nozzle temperature by 5°C increments
• Reduce print speed — slower speed gives each layer more time in contact with the hot nozzle
• Reduce layer height — thinner layers bond more readily than thick ones
• Check for moisture in the filament — wet filament produces brittle layers that separate easily; dry filament in an oven at 45°C for 4–6 hours before printing

Nozzle clogs are caused by debris in the filament, carbonised filament residue from printing at too-high temperatures, moisture in the filament creating steam and char, or switching to a lower-temperature filament without purging high-temperature residue first.

• Perform a cold pull: heat to 200°C, push filament through manually, cool to 90°C, pull the filament out sharply — the plug pulls debris with it
• Repeat cold pull 3–5 times until the pulled plug comes out clean with no black contamination
• For severe clogs, heat to maximum temperature and use a 0.3mm acupuncture needle or nozzle cleaning needle to break the obstruction
• Replace the nozzle if cleaning fails — brass nozzles are inexpensive and wear over time, especially with abrasive filaments

First layer adhesion failure is almost always one of four things: the bed is dirty, the Z-offset is too high, the bed temperature is too low, or the bed surface is inappropriate for the filament being used.

• Clean the bed with IPA immediately before the print — this is the single most effective adhesion fix
• Decrease Z-offset — bring the nozzle closer to the bed so the first layer is firmly squished in
• Increase bed temperature — PLA needs 55–65°C; PETG needs 70–85°C; ABS and ASA need 100–110°C
• Check the bed surface — PEI spring steel (standard on Neptune 4 series) grips PLA and PETG well when clean and at the correct temperature; glass may need glue stick or hairspray for some filaments