Corners lift and the part curls up (warping)

Symptom

The corners or edges of the part come away from the bed and curl upwards while printing, especially on large parts and with ABS, ASA or PC. The base ends up bowed and sometimes the part comes loose.

Likely causes, from most to least likely

1. Plastic shrinking as it cools suddenly: the part contracts and pulls on the corners. It is worse on large parts and with high-temperature materials such as ABS, ASA or PC.
2. ABS, ASA or PC printed without an enclosure, in a cold room or with draughts (open window, air conditioning nearby).
3. Poor first-layer adhesion: dirty surface or nozzle slightly too high.
4. Too much part cooling for materials that don't tolerate it well (ABS, ASA, PC) or on the first layers.
5. High print speed, which doesn't let layers settle and fuse properly.

Checks to tell which one it is

• Think about material and size: with ABS, ASA or PC and large parts, warping is very likely without an enclosure.
• Look for draughts: windows, doors, fans or air conditioning near the printer.
• Check the first layer: round, loose lines mean the nozzle is too high; also look for fingerprints or grease on the bed.
• Check the part cooling fan speed in the material profile and whether it is off for the first layers.

Before you start

Before taking anything apart, cleaning or adjusting it, switch the printer off and unplug it, unless a step says otherwise, and do not touch the nozzle, the heater block or the bed until they have cooled down. If in any doubt about electricity, heat or moving parts, stop and ask a professional.

Step-by-step fix

1. Clean the bed and adjust the first layer

   Clean the surface while cold with isopropyl alcohol of at least 90%. If the first layer is slightly high, lower the nozzle a little (Live Adjust Z or Z offset) to gain adhesion, without over-squishing it.

   Check: The first layer is flat and well stuck across the whole part.

   If that does not fix it: Add a brim.

2. Add a brim or small discs at the corners

   Enable a brim to increase the gripping area. If it still lifts at one specific spot, add a small helper shape to the model, such as a very thin cylinder, right at that corner.

   Check: The corners stay down until the end.

   If that does not fix it: Apply a thin layer of glue stick.

3. Use glue stick

   With the bed cold, spread a thin layer of glue stick: it improves adhesion and also protects the surface.

   Check: The corners stay down on the next print.

   If that does not fix it: Control the surrounding temperature.

4. Protect the part from cold and draughts

   Move the printer away from windows and air conditioning. For ABS, ASA or PC use an enclosed printer or an enclosure; for PLA and PETG, on the other hand, it is not a good idea, as they need a lot of cooling.

   Check: The part cools more evenly and doesn't lift.

   If that does not fix it: Adjust part cooling.

5. Adjust part cooling

   Turn the part cooling fan off for the first layers. With ABS, ASA or PC keep it off or very low; according to Prusa, only if overhangs or small parts fail can you try a low speed (10-20%).

   Check: No lifted corners or cracks between layers appear.

   If that does not fix it: Print slower.

6. Print slower

   Reduce print speed so the layers settle and fuse properly: the part warps less.

   Check: The part finishes with no lifted corners.

   If that does not fix it: If it still lifts, consider a less warp-prone material for that part (Prusa suggests PETG as an alternative to ABS for large parts).

Prevention

• Print ABS, ASA and PC enclosed and away from draughts.
• Keep the surface clean and free of grease.
• Use a brim on large parts.

Still not fixed?

Tell usi3d's AI about your case: choose your printer, describe what you see and add photos if you like. It proposes checks step by step, with their sources.

Tell the AI about your case

Printers it applies to

Any FDM (filament) 3D printer, from any brand.

Official sources

This guide summarises the official documentation linked here:

• Warping · Prusa Research
• Cooling · Prusa Research
• Layer separation and splitting FDM · Prusa Research