Saturn 4 Ultra 16K: replacing the PFA film of the resin tank, or the tank leaks resin

Symptom

The PFA film of the Saturn 4 Ultra 16K resin tank is whitened, scratched, damaged or aged, resin escapes from the tank and cured resin appears on the LCD, or prints come away from the centre of the build plate and stay in the tank.

Likely causes, from most to least likely

1. The film is in poor condition: whitened, scratched, damaged or aged.
2. A torn or badly fitted film lets resin escape, which then cures on the LCD.
3. Cured residue in the tank after a failed print.
4. When fitting a new film, the two heating points are left unpierced and the film covers the tank contacts.

Checks to tell which one it is

• Take the tank out and check whether the film is whitened, scratched, torn or aged, or whether its tension is not the usual one.
• With the printer off, look for cured resin on the LCD.

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. Remove cured resin from the LCD

   Wearing gloves, dab an alcohol-soaked cotton swab around the cured resin, a little at a time, and wait about 5 minutes for it to soften. Remove it with a scraper and clean the LCD with a lint-free cloth and alcohol. Elegoo says this method only applies to screens with a tempered glass film.

   Check: The LCD is clean.

   If that does not fix it: Repeat the step, then check the film.

2. Remove the old film

   Wear gloves and safety glasses, with ventilation. Lift the cover, loosen the 2 screws on the sides of the tank and take it out. With the 3.0 mm key loosen the 5 screws underneath and, with the 2.5 mm key, the 7 screws of the film assembly, and take it out. With the 2.0 mm key loosen the 24 screws of the clamping plates, remove the plates and the old film and wipe the resin off the plates with tissue.

   Check: The plates are clean.

   If that does not fix it: Clean them again before fitting the new film.

3. Fit the new PFA film

   Place an 80 × 80 × 8 mm foam block in the centre of the lower plate. Peel the protective films off both sides of the film (PFA has no front or back), line it up with the four corners leaving the same margin, close the upper plate and tighten the 24 screws diagonally with the 2.0 mm key. Remove the foam and trim the excess film around the edge with a utility knife.

   Check: The film is taut and flat, without wrinkles.

   If that does not fix it: If it is wrinkled, refit it.

4. Pierce the heating points and refit

   Pierce the 2 heating point holes with a screwdriver. Wipe the grooves of the tank and fit the film assembly (the heating points have a fixed position). Tighten the 7 screws (2.5 mm) diagonally, first to two-thirds of the torque and then fully, and the 5 underneath (3.0 mm). Fit the tank and tighten its 2 screws.

   Check: The tank does not leak and the printer detects and heats it.

   If that does not fix it: If it leaks, refit the film; if a tank or heating error appears, check its contacts.

5. Clean the tank after every failure

   After a failed print, use the tank cleaning function («Clean Tank») to remove cured resin and filter the resin before printing again.

   Check: No cured residue is left in the tank.

   If that does not fix it: Remove it with a plastic scraper before printing.

Prevention

• Filter the resin before every print and clean the tank after every failure: it protects the film and the LCD.
• Check the film often and replace it if it is whitened, scratched or aged.
• According to Elegoo, the LCD warranty does not cover damage from resin leaks.

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

Elegoo Saturn 4 Ultra 16K.

Official sources

This guide summarises the official documentation linked here:

• Release Film Replacement (Saturn) · Elegoo
• Saturn 4 Ultra 16K · Elegoo
• How to Clean Resin Off the LCD Screen · Elegoo
• Model Detachment at Center of Build Plate · Elegoo
• LCD Screen Display Issue · Elegoo