The part is stuck so hard to the bed it won't come off

Symptom

When the print finishes, the part won't come off the bed or only comes off with a lot of force. Sometimes it tears pieces out of the surface or leaves marks, especially with PETG on smooth PEI.

Likely causes, from most to least likely

1. PETG (or others such as ABS, ASA or PC) on clean smooth PEI without a separation layer: adhesion can be so strong that removing the part tears off the PEI.
2. Trying to remove the part while the bed is still hot.
3. Over-squished first layer (nozzle too low), which increases adhesion.
4. Cleaning smooth PEI with acetone right before printing PETG.

Checks to tell which one it is

• Check which material and surface you are using: PETG on smooth PEI without glue is the most problematic combination.
• Make sure the bed and part have cooled down completely before trying to remove it.
• Look at the underside of earlier parts: if the first layer was very squished and almost see-through, the nozzle was too low.

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. Let it cool down completely

   Wait until the bed and part are at room temperature. If your printer has a flexible sheet, take it off and flex it: the part usually pops off without tools.

   Check: The part comes off without forcing it.

   If that does not fix it: Use a few drops of isopropyl alcohol.

2. A few drops of isopropyl alcohol at a corner

   With the bed cold, put a few drops of isopropyl alcohol at one corner of the part and flex the sheet again. Prusa suggests this for PETG parts that are stuck too hard. Avoid prying with force: with PETG on smooth PEI you can tear the PEI layer off.

   Check: The part separates without damaging the surface.

   If that does not fix it: If the surface has been damaged, ask your printer manufacturer whether it can be restored or the sheet needs replacing.

3. Stop it happening again

   For PETG, ABS, ASA or PC on smooth PEI, first apply a thin layer of glue stick as a separation layer, or use a textured or satin sheet. Don't clean with acetone right before printing PETG and don't over-squish the first layer.

   Check: The next part comes off once cooled, with no marks on the surface.

   If that does not fix it: Raise the first-layer height slightly until it is flat but not see-through.

Prevention

• Use a separation layer (glue stick) with PETG, ABS, ASA and PC on smooth PEI.
• Always remove parts with the bed cold.
• Set the first layer so it is flat, without over-squishing it.

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Printers it applies to

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

Official sources

This guide summarises the official documentation linked here:

• Print surface preparation · Prusa Research
• Smooth Steel Sheet · Prusa Research
• First layer issues · Prusa Research
• PETG · Prusa Research