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Fix

Warping

Corners or edges of a print curl upward and pull away from the bed as plastic cools and shrinks unevenly, distorting the base of the part.

Likely causes
  1. Uneven cooling and shrinkage
  2. Poor first-layer adhesion
  3. Drafts or cold room
  4. Bed temperature too low
  5. Large flat parts with sharp corners
  6. Too much part cooling fan
Warping
The bottom edges, especially sharp corners, lift off the bed, leaving a curved underside and sometimes cracks or a bowed shape further up.

What warping is and how to confirm it

Every thermoplastic shrinks as it cools. The first layers sit on a heated bed while upper layers cool faster, so the top of the part shrinks more than the bottom. That pull concentrates at corners and long edges, and when it beats the grip of the first layer, the corner peels up. Warping can ruin dimensional accuracy, knock the print loose, or cause the nozzle to collide with the raised edge.

Confirm it by placing the finished part on a flat surface. If corners rock or you can slide paper under the edges, it warped. During printing, watch the corners in the first 20 to 30 minutes; lifting usually starts there. Horizontal cracks higher up in ABS or ASA parts are the same problem showing up as layer splitting.

Causes, most likely first

  1. Weak first-layer adhesion from a dirty bed, wrong Z-offset or bad leveling.
  2. Material choice. ABS, ASA and nylon shrink far more than PLA.
  3. Drafts and room temperature. Air conditioning, open windows or a fan nearby cool one side faster.
  4. Bed temperature too low for the material.
  5. Too much part cooling on the first layers or on shrink-prone materials.
  6. Geometry. Large footprints and sharp 90 degree corners concentrate stress.

Fixes, cheapest and fastest first

1. Clean the bed

Wipe the plate with isopropyl alcohol (90 percent or higher). For textured PEI that has lost grip, wash with warm water and dish soap, rinse, and dry. Skin oil from handling is enough to cause a corner to lift.

2. Fix the first layer

Relevel the bed and set the Z-offset so the first layer is gently squished: lines should be flat and touching with no gaps, not rounded. Print the first layer slowly, around 15 to 25 mm/s, and turn the part cooling fan off for the first 2 to 3 layers.

3. Raise the bed temperature

Typical starting points: PLA 55 to 65 °C, PETG 70 to 85 °C, ABS and ASA 95 to 110 °C. Going a few degrees higher helps grip, but too hot on PLA can cause elephant foot.

4. Add a brim

A brim of 5 to 10 mm adds surface area right where lifting starts. Mouse ears, small discs at each corner, work for parts where a full brim is hard to remove.

5. Control the air around the print

Block drafts. For ABS and ASA an enclosure is close to mandatory; an inside air temperature of 40 to 50 °C makes a large difference. Reduce part cooling to 0 to 30 percent for these materials.

6. Use an adhesion aid

A thin layer of glue stick or a dedicated adhesive helps on smooth glass or worn sheets. For PETG on smooth PEI, glue stick also acts as a release layer so the part does not tear the sheet.

7. Adjust the model

Round sharp corners with a 2 to 5 mm fillet, split very large flat parts, or orient the part to reduce footprint length. Lower infill density also reduces internal stress slightly.

Material notes

  • PLA: rarely warps if the bed is clean and the room is not drafty. Large flat plates may still lift; use a brim.
  • PETG: mild shrinkage; mostly an adhesion issue. Keep the fan low for the first layers.
  • ABS/ASA: the classic warping materials. Enclosure, hot bed, brim and minimal fan.
  • TPU: almost never warps; bed adhesion is usually too strong rather than too weak.

Prevention checklist

  • Clean the bed before each print and avoid touching the surface.
  • Check the first layer visually on every new print.
  • Use the correct bed temperature for the material.
  • Default to a brim on large or sharp-cornered parts.
  • Keep the printer away from vents, windows and fans.
  • Let the bed cool before removing parts to avoid bending the base.

Frequently asked questions

Do I need an enclosure to stop warping?

For PLA and PETG, usually not; a clean bed, a correct first layer and a draft-free room are enough. For ABS, ASA, nylon and polycarbonate, an enclosure is one of the most effective fixes because it keeps the whole part warm and reduces the temperature difference between layers. Even a cardboard box or a simple tent around the printer helps, as long as electronics stay ventilated.

Why does my print warp only on one side?

One-sided warping usually points to a draft or uneven heat. Air from a vent, window or nearby fan cools that side faster. It can also be a bed that is not level, giving a thinner and weaker first layer on one side, or a bed heater with an uneven temperature spread near the edges. Check leveling first, then look at airflow around the printer.

Is a brim or a raft better against warping?

A brim is usually the better first choice. It adds grip at the edges where lifting starts, uses little material, and leaves the bottom surface flat. A raft lifts the part onto a sacrificial base, which can help on difficult materials or uneven beds, but it costs time, makes the bottom rougher and can be hard to separate. Try a 5 to 10 mm brim before a raft.

Other print problems

Blobs and zitsClogged nozzleElephant footGhosting (ringing)