Why is my 3D print warping?
Warping is when a print's corners curl up and peel away from the bed, leaving a base that's no longer flat — or lifting so far the nozzle starts dragging through it. It looks like an adhesion problem, but the cause is different: the plastic is fighting itself as it cools.
As upper layers cool and shrink, they pull the corners inward and up.
The short answer
What's actually happening
Every plastic shrinks as it cools from print temperature down to room temperature. The freshly-laid top layers are hot and expanded; the moment they cool, they contract and tug on everything below. Corners and edges have the most leverage, so that's where the pull wins and the part lifts. Two things decide who wins: how much the material shrinks, and how firmly the base is held down.
Lever 1: Keep it warm and evenly cooled
Fast, uneven cooling is what creates the tension in the first place. Turn on theheated bed — around 60 °C for PLA, 70–80 °C for PETG, 90–100 °C for ABS/ASA — so the base stays soft and relaxed. Kill draughts: an open window or an AC vent blowing across the printer warps parts that would otherwise be fine. For high-shrink materials (ABS, ASA) an enclosure keeps the surrounding air warm and still, and for them it's close to essential.
Lever 2: Give the base more grip
The better the first layer holds, the more shrinkage it can resist before letting go. Start with a spotlessly clean plate (seethe first-layer guide). Add abrim — a wide flat skirt around the base — to multiply the contact area at the corners where lifting starts. A swipe of glue stickadds tack on smooth plates. Together these often hold a mildly-warping part flat with no other change.
Watch out
The fastest answer: pick a material that doesn't warp
If a part doesn't need heat resistance or outdoor toughness, print it in PLA and warping mostly disappears — it shrinks the least of any common filament. Reach for the high-shrink materials only when the job demands them. Not sure which yours needs? The Filament Picker flags the warp-prone ones before you commit.
Warping quick-fix list
- Turn the heated bed on and up to the material's range.
- Close windows and redirect any fan or vent blowing on the printer.
- Clean the plate, then add a brim to reinforce the corners.
- For ABS/ASA: enclose the printer and cut part cooling right down.
- Still fighting it? Switch the part to PLA if the job allows.
Common questions
Why do the corners of my 3D print lift up?
Because plastic shrinks as it cools, and the corners have the most leverage. As upper layers cool and contract, they pull the edges inward and up, peeling them off the bed. It's worst with materials that shrink a lot (ABS and ASA) and in rooms with cold draughts.
Does PLA warp?
Rarely, and mildly. PLA shrinks very little as it cools, so on a clean, level, heated bed it usually stays put. If your PLA is warping, suspect a dirty plate, no bed heat, or a cold draught before you blame the material. PETG warps a little more; ABS and ASA warp a lot and really want an enclosure.
Will an enclosure stop warping?
For high-shrink materials, it's the single biggest fix. An enclosure keeps the air around the print warm and still, so the part cools slowly and evenly instead of contracting fast at the edges. For ABS and ASA it's close to essential; for PLA and PETG it's usually unnecessary and can even trap too much heat.
Should I turn off the part cooling fan to stop warping?
For ABS and ASA, yes — run little or no part cooling, because fast cooling is exactly what causes their warping. For PLA, no — PLA needs the fan for clean overhangs and detail, and it barely warps anyway. Match the fan to the material, not to the symptom.