Supports fail or the part breaks away from them

Symptom

The supports stay on the build plate but the part comes loose and drops into the vat; some supports do not form or break, and parts of the model come out incomplete or deformed.

Likely causes, from most to least likely

1. The supports are too thin or too few for the weight of the part.
2. Normal layer exposure is too short and the supports end up weak.
3. The part is solid and too heavy for the supports.
4. The build plate lifts too fast or not high enough, and the part does not release cleanly from the film at each layer.
5. The orientation creates suction cups or rests the supports on large flat surfaces.
6. The film is dirty or, more rarely, the UV light is failing.

Checks to tell which one it is

• If the supports stayed on the plate and the part is in the vat, the supports could not hold its weight or the exposure is too short.
• If some supports are missing but the bottom layers are fine, suspect normal layer exposure, lift height or the resin profile.
• Print a manufacturer's test model: if it prints fine, the problem is in your settings; if it also fails, check the film and the machine.
• Check whether the part is large and solid or has cavities.

Before you start

Uncured resin irritates skin and eyes: wear nitrile gloves and safety glasses, ventilate the room and do not look at the UV light. Before taking anything apart or cleaning it, switch the printer off and unplug it, unless a step says otherwise. If in any doubt, stop and ask a professional.

Step-by-step fix

1. Clean the vat before trying again

   Wearing nitrile gloves, remove the fallen part and any debris with a plastic scraper and filter the resin. Do not print again with debris in the vat.

   Check: The film is clean with no pieces on it.

   If that does not fix it: Follow the cured debris in the vat sheet.

2. Strengthen the supports

   In the slicer, increase support density and thickness and the diameter of the support tips. Avoid resting large flat surfaces on supports: rotate the part on the X and Y axes to tilt it.

   Check: In the preview, every overhanging area has enough supports.

   If that does not fix it: Adjust the exposure.

3. Adjust normal layer exposure

   Use the official profile for your resin. If the supports come out weak or do not form, raise the normal exposure; as a guide, Phrozen suggests 10% more.

   Check: The supports come out whole and rigid.

   If that does not fix it: Make the part lighter.

4. Hollow the part and add drain holes

   Hollow out solid parts and add drain holes; without them, resin is trapped inside. As a guide, Phrozen asks for at least 2 holes of 3 mm or more near the base, and walls of 1.5 mm on small parts or 2 mm on large ones.

   Check: The part is lighter and resin flows out of the holes when washing it.

   If that does not fix it: Peel more slowly.

5. Peel more slowly

   Lower the lift speed and increase the lift height and the wait time after the light turns off. As a guide, Phrozen suggests a lift speed below 40 mm/min. Also clean the Z axis.

   Check: The part releases from the film at every layer without jerks.

   If that does not fix it: Check the film and the UV light.

6. Check the film and the UV light

   If the test models also fail, clean or replace the film and run your printer's screen test (LCD screen and UV light sheet).

   Check: The test model prints complete.

   If that does not fix it: Contact the manufacturer's support with photos or video of the failure.

Prevention

• Check in the preview that no area hangs without support.
• Hollow out large solid parts and give them drain holes.
• Use your resin's profile and keep the film and the Z axis clean.

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 resin (MSLA/SLA) 3D printer, from any brand.

Official sources

This guide summarises the official documentation linked here:

• Print detached from supports (SL1/SL1S) · Prusa Research
• Broken supports (SL1/SL1S) · Prusa Research
• Why Did the Model Not Print While the Supports Printed? · Phrozen
• Why Did Some Supports Not Print? · Phrozen