Cured resin debris floating in the vat

Symptom

After a failed print, bits or sheets of hardened resin float in the vat or stick to the film, and the next parts come out with holes or fail.

Likely causes, from most to least likely

1. A failed print has left cured or partly cured pieces in the resin or stuck to the film.
2. Particles or dirt on the film or in the resin block the light and leave holes in the parts.

Checks to tell which one it is

• Wearing gloves, gently run a plastic scraper along the bottom to feel for stuck pieces.
• Look at the resin and the film against the light for particles.
• If parts come out with holes, suspect dirt or particles on the film or in the resin.

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. Use the vat cleaning function

   If your printer has one, run it: it cures a thin layer over the whole bottom that traps the debris and comes out in one piece. Phrozen, for example, cures it for about 15 seconds and lifts it from a corner with a folded piece of paper.

   Check: The layer comes out whole with the debris stuck to it.

   If that does not fix it: Remove the debris by hand.

2. Remove debris by hand, without metal

   Wearing nitrile gloves, take out the vat and lift off the pieces with a plastic scraper; never use metal tools, which damage the film.

   Check: Running the scraper over it, you feel nothing stuck.

   If that does not fix it: Filter the resin.

3. Filter the resin

   Strain the resin through a fine paint filter (Formlabs gives 190 microns) into a container and pour it back into the vat, not into the bottle of fresh resin, so it does not get contaminated.

   Check: No particles are left in the filtered resin.

   If that does not fix it: Clean the film.

4. Clean and inspect the film

   Clean the film as your manufacturer indicates: Prusa uses hot soapy water for a cloudy film, and Formlabs uses isopropyl alcohol with a lint-free cloth on the outer side. Let it dry before refitting the vat.

   Check: The film looks clear and spotless.

   If that does not fix it: If it stays cloudy or marked, replace the film (resin leak and torn film sheet).

Prevention

• Check the vat and filter the resin after every failed print.
• Do not leave cured debris in the vat: it can make prints fail and damage the screen.

Still not fixed?

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Printers it applies to

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

Official sources

This guide summarises the official documentation linked here:

• Resin filtration · Formlabs
• Inspecting and cleaning resin tanks (Form 4 and Form 4L generation) · Formlabs
• Holes in print (SL1/SL1S) · Prusa Research
• Cleaning the Resin Vat · Phrozen