# 3D print corners lift off the bed: warping and bed adhesion

> Fix warping on robot chassis parts: clean the bed, level and set the first layer, raise the bed temperature, add a brim and avoid drafts.

Canonical: https://roboticsengineering.in/fix/3d-print-warping-corners-lift-bed-adhesion/ | Published: 2026-11-03 | Updated: 2026-11-04

**Clean the bed, get the first layer right and add a brim.** Those three fixes cure most warping.

## What the message means

Plastic shrinks as it cools. Large flat parts pull at the corners, and if the first layer does not grip, the corners lift.

## Fix it in this order

1. Wash the bed with dish soap and water, or wipe it with isopropyl alcohol.
2. Level the bed and set the nozzle height so the first layer is slightly squashed.
3. Raise the bed temperature a little within the range for your plastic.
4. Add a brim of a few millimetres around the part in the slicer.
5. Keep drafts and open windows away from the printer, or use an enclosure.
6. Slow the first layer and turn the cooling fan off for it.
7. Round the sharp corners of large parts in the design.

## Why it happens

Plastic shrinks as it cools. The upper layers pull inward as they cool while the first layer is held by the bed, and on a large flat part the pull is strongest at the corners. If the grip is weaker than the pull, the corner lifts.

A clean bed and a correct first layer raise the grip. A brim adds contact area, and shielding the print from drafts slows the uneven cooling. Materials differ in how much they shrink, so a part that sticks in one plastic may warp in another.

## If you see this, do this

| You see | Do this |
| --- | --- |
| Corners lift | Brim, bed temperature and drafts. |
| First layer will not stick at all | Clean and re-level. |

## Related

[wheel slips on the shaft](https://roboticsengineering.in/fix/3d-printed-wheel-or-gear-slips-on-motor-shaft/), [stringing](https://roboticsengineering.in/fix/3d-print-stringing-wisps-retraction-wet-filament/).

Last reviewed: November 2026. These are the usual causes and the order that finds them fastest. Test on your own board; clones and cables differ.

## Why this happens

Warping is stress release. As each new layer cools, it shrinks and pulls on the layers below. The first layers are held by the bed, so the stress builds up in the part, and a corner is where the pull is concentrated. If the bond between the first layer and the bed is weaker than that pull, the corner peels up. How hard it pulls depends on the plastic: PLA shrinks little, while ABS and some nylons shrink much more, and bigger flat parts build more stress.

Bed temperature helps by keeping the lower layers closer to the plastic’s softening point, so they relax instead of fixing the stress in. Typical starting bed temperatures are around 50 to 60 degrees C for PLA, 70 to 85 for PETG and 90 to 110 for ABS, but check the figures for your filament. Cooling air, open doors and fans make it worse by cooling one side faster than the other.

## How to confirm the cause

- Notice which corners lift first. Lifting on the side facing a door or fan points to drafts; lifting at all four corners points to adhesion or shrinkage.
- Print a single-layer square about 50 mm across. The lines should join into a flat sheet with no gaps and no ridges. Gaps mean the nozzle is too high; a rough, ridged surface means it is too close.
- Check the real bed temperature with a thermometer, since some printers read a few degrees off.
- Wash a section of the bed with dish soap and print again. If adhesion improves, the surface was contaminated by finger oil or dust.
- Print the same part with a 5 mm brim. If it no longer lifts, it was a contact area problem.

## Worked example

A slicer settings walk-through for a 100 mm flat plate in PLA. These are starting points, not tested values; adjust them for your printer and filament.

```
Bed                : cleaned with soap, dried
Bed temperature    : 60 C (first layer)
First layer height : 0.2-0.3 mm, line width 120 percent
First layer speed  : 20 mm/s, part fan off
Brim               : 5 mm
Corners            : radius 3 mm in the model
Test               : print 50 mm square, one layer, check joins
```

## Common mistakes

- Touching the bed surface with bare fingers before a print.
- Setting the nozzle too high on the first layer to avoid scraping.
- Using too much glue stick, which makes a thick layer that peels.
- Printing ABS or similar in an open, drafty room and expecting PLA behaviour.
- Making a very long brim and not checking whether the actual problem is a bed that is not flat.

## If this did not fix it

- Check whether the bed is flat when hot. A bed that warps with heat gives uneven adhesion.
- Check for a partial nozzle clog or wet filament, which cause weak first-layer lines.
- Check the first layer speed and flow in the slicer; too fast or too little extrusion gives poor bonding.