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Photon Mono M7 Pro: replacing the ACF film (bumps, cured resin, leaks or code 305)

Guide based on the manufacturer's official documentation; usi3d has not yet verified it on a machine.

Technology: Resin · Brand: Anycubic · Symptoms: Resin leak or torn film in the vat, The print sticks to the vat film (FEP), The printer shows an error code or message · Updated on 10 October 2026

Symptom

On the Photon Mono M7 Pro the ACF film of the resin vat has bumps, wrinkles, stains or cured resin on it, it leaks resin, the printer reports «Residue detected, please clean and restart printing (CODE: 305)» or asks you to replace the film when it reaches its usage cycle.

Likely causes, from most to least likely

  1. The film has reached the end of its life: the M7 Pro ACF film lasts about 45,000 layers of normal printing and the printer warns you with its counter.
  2. Cured resin residue in the vat or on the film after a failed print.
  3. Bumps on the film, or scratches from scraping the vat with a metal spatula.
  4. The resin was poured out from the back of the vat, which can damage it.
  5. The new film was fitted badly: wrinkled, upside down or without tightening the screws diagonally.

Checks to tell which one it is

  • After printing, remove the vat and look for cured resin or bumps on the film.
  • Check the print and layer counter the printer shows for the film.
  • If you see small bubbles in the floating platform sticker (which isolates the machine if the film breaks), they are normal and do not matter.

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 residue (code 305)

    Wearing gloves, first check the build plate: if it has cured resin, remove it with the metal scraper; if it has bumps, replace it. Then use the printer's «Cleaning» function and remove the cured resin from the vat with a plastic scraper, never a metal one. Stir the resin to look for leftover pieces and filter it.

    Check: No cured resin is left in the vat or on the build plate.

    If that does not fix it: Check the film (next step).

  2. Check the film

    Pour the resin back into the bottle and look for bumps or cured resin on the film. If there are any, or stains that will not come off, replace it (next steps).

    Check: The film is smooth and clean.

    If that does not fix it: Replace the film (next steps).

  3. Empty and clean the vat

    Wear gloves and safety glasses, with ventilation. If cured resin remains, tap «Tools» → «Cleaning» → «10s» and remove the residue with a scraper without scratching the film. Pour the resin out from the front of the vat, never the back, through a funnel with a filter. Spray alcohol on the film and wipe it with a lint-free cloth until no resin drips when the vat is turned over.

    Check: The vat is empty and clean.

    If that does not fix it: Clean it again before taking it apart.

  4. Remove the old film

    Turn the vat over and remove the 4 diagonal screws (M3×14) with the 2.5 mm key and the other 18 (M3×12) with the 2.0 mm key. Take out the steel ring, loosen the 22 screws (M3×5) that hold the film with the 2.0 mm key, remove the old film and clean the ring with alcohol and a lint-free cloth.

    Check: The ring is clean, with no resin residue.

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

  5. Fit the new ACF film

    Peel the protective films off the new film. The large hole of the ring goes up; the smooth side of the film, with the yellow sticker, faces up and the frosted side faces the light. With the film perfectly flat, tighten 4 screws diagonally and then the other 18; fit the assembly to the vat and tighten the 4 screws (2.5 mm) diagonally and the 18 (2.0 mm). Trim the excess with a utility knife, taking care not to cut yourself.

    Check: The film is free of wrinkles and damage.

    If that does not fix it: If it is wrinkled, refit it: wrinkles spoil the print.

  6. If resin splashes out of the vat

    If resin splashes out while printing, it is caused by vacuum suction, which makes the release force too high: drill drainage holes in the model to reduce it.

    Check: The resin stops splashing.

    If that does not fix it: Contact Anycubic support.

Prevention

  • Before printing, check that the film is not damaged or leaking: if it is, replace it so the machine is not damaged.
  • Replace the film when the printer prompts you or when it has cured resin or stains.
  • If you will not print for 48 hours, pour the filtered resin back into the bottle and store it away from UV light.

Still not fixed?

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Printers it applies to

Anycubic Photon Mono M7 Pro.

Official sources

This guide summarises the official documentation linked here:

This guide is general information: usi3d has summarised it from the official documentation linked here, and it may not match your model, its version or its firmware. If in doubt, follow the manual and the support of your printer's manufacturer. You decide what you do with your machine, and working on it may affect its warranty.

Products that may help

Chosen for the symptoms in this guide and the printers it applies to, not for the commission. Check that they work with your printer before buying.

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