3D printer troubleshooter

Stringing

Strings are plastic that oozes from the nozzle while it travels between parts of the print. Prusa's stringing guide names too high a nozzle temperature and retraction settings as the usual causes.

• Lower the nozzle temperature by 5 to 10 °C and print again.
• Check retraction is on. Direct drive extruders need short retractions and Bowden setups longer ones, so start from your printer's stock profile.
• Turn on wipe while retracting, and avoid crossing walls on travel moves.
• Dry the filament or try another spool. Damp filament strings badly.
• Clean old plastic off the nozzle, which can drag strings onto the print.

Warping

Corners lift when the part shrinks as it cools. It is worst on large parts in ABS, ASA and PC, according to Prusa's warping guide.

• Clean the build plate with 90% or stronger isopropyl alcohol so there is no grease on it.
• Add a brim to give the corners more grip.
• For ABS, ASA and PC, keep the air around the printer warm and still. An enclosure helps; a draft from a window or an air conditioner makes it worse.
• For PLA and PETG, check the part-cooling fan is working. Those two need cooling, so do not print them in a hot, closed enclosure.
• Slow the print down for materials that warp easily.

First layer and bed leveling

Most failed prints start with the first layer. If the nozzle is too close, plastic cannot get out; too far, and it will not press into the bed. Prusa's first layer guide covers both.

• Run your printer's bed leveling or first layer calibration, then fine-tune the Z offset while the first layer prints.
• Do not squash the first layer to force adhesion. Too low can damage the build plate.
• Wipe the plate with isopropyl alcohol and keep fingers off it. On a smooth PEI sheet, use a glue stick as a release layer for PETG, which can bond too strongly.
• Slow the first layers down, and use the bed temperature your slicer's profile sets for the filament.
• Make sure the plate is seated flat with nothing trapped under it.

Elephant foot

The first layer is pressed onto a hot bed, so it comes out a little wider than the layers above. That lip is elephant foot.

Slicers shrink the first layer to compensate. In PrusaSlicer it is Print settings, Advanced, Elephant foot compensation, and Prusa's guide says about 0.2 mm works for a 0.4 mm nozzle. OrcaSlicer has the same setting under Precision.

If the lip is large, the nozzle may also be set too close to the bed. Check the first layer height before raising the compensation.

Every fault guide

• Z banding
• Under-extrusion
• Heat creep
• Layer shifting
• Blobs and zits
• Flow rate calibration