Here is how to replace an FEP film on an Anycubic Photon vat: drain and clean it, pull the underside screws (M2.5 hex), free the steel ring (M2.0 hex), peel both protective layers off the new sheet, lay it over a 13 mm spacer, tighten diagonally, trim, reinstall, then tension-check and leak-test with IPA.
That sequence is from Anycubic’s FEP maintenance tutorial, shot on the Photon Mono X vat: 14 screws hold the film module and 22 clamp the film in its steel ring. Its 240 × 165 mm sheet also fits the Mono X 6K and M3 Plus. Screw counts vary (the M3 ring uses 18 bolts, per lina makes’ M3 walkthrough), but the order and the tension logic carry over.
When does an FEP film need replacing?
Replace the film when it is cloudy, deeply scratched or dented, or punctured. Light surface scratches alone are not a reason, because every used film has them. Anycubic lists those three triggers in its replacement guide, and its Mono X tutorial puts the film’s usage life at about 30,000 layers. If cured resin shows up on the LCD when you lift the vat out, the film already has a hole.
Holes too small to see still leak. Anycubic’s test is to pour a small amount of isopropyl alcohol into the empty vat and look for leakage underneath. The community Photonsters FAQ agrees: replace a punctured or torn film immediately. Otherwise wait until it is too scratched or cloudy, which on a well-kept vat takes months.
Rule out other causes before cutting a new sheet. Prints tearing off onto the film usually come down to leveling, exposure, cold resin or peel force, sorted by symptom in resin sticking to the FEP on a Photon Mono. A new film will not fix a tilted plate.
What do you need before you start?
You need two hex keys, a spacer, a blade, a pick, IPA and a film cut for your vat. The film is the part people get wrong, because Anycubic sells FEP, nFEP and ACF films across its Photon range.
- M2.5 and M2.0 hex keys. Those are the sizes Anycubic calls for on the Mono X and M5s vats. Use hand keys: Prusa’s SL1 film guide tells owners to avoid cordless screwdrivers because of the torque.
- Tweezers or a scribe to pierce the film over each screw hole.
- A utility knife with a fresh blade for trimming.
- A spacer about 13 mm tall. Anycubic uses a bottle cap. Photonsters specify one 30 mm across and 13 mm high.
- Nitrile gloves, IPA, lint-free towels, a plastic scraper and a filter funnel. Never use metal on the film or the ring.
- The right film. The M5s ships with ACF film. Anycubic’s M5s release-film guide says standard FEP can replace it, but the printer then loses its high-speed printing mode. Match the sheet size to your vat as well as the film type.
Step by step: replacing the film on a Photon vat
- Drain and clean the vat. Pour the resin back through a filter funnel so cured flakes do not end up under your next print. Work on paper towels with gloves on.
- Remove the film module. Turn the vat upside down. On the Mono X, 14 M2.5 screws release the steel ring and film as one module.
- Separate the ring from the old film. Remove the M2.0 clamp screws (22 on the Mono X) and lift the old sheet out. lina makes suggests noting how tight the bolts were so you can match it on reassembly.
- Clean every mating surface. Wipe the ring and vat with IPA. Prusa’s rule for its own tank applies: “The edges must be perfectly clean, otherwise, the tank will leak.” One cured flake under the ring is a leak path.
- Peel the protective layers. Elegoo’s Saturn guide and Prusa both say to remove the plastic from both sides. Photonsters’ test if unsure: drip resin on the film and hold it vertical. Clean run-off means bare FEP; smearing means a layer is still on.
- Set the slack. Lay the frame on the bench, put the film over it and place the spacer under the centre so the film bulges slightly. The frames fit together one way only. For ACF on the M5s, Anycubic puts the matte side toward the table and the slanted-hole frame facing down.
- Pierce and fasten. Push the tweezers through the film over each hole. Start with diagonally opposite corner screws, keeping ring and film from shifting, then fit the rest. Prusa’s refinement: take every screw halfway first, then tighten fully in the same order.
- Trim. Cut the excess film along the frame edge.
- Reinstall the module. Tighten the M2.5 screws diagonally. Anycubic’s pass check: the steel ring sits lower than the black notch on the vat, with no wrinkles in the film.
- Reset the layer counter. Photons that track release-film layers need the counter reset in settings, as the M5s guide notes.
Elegoo uses the same slack principle with different hardware: its Saturn procedure puts an 80 × 80 × 8 mm sponge under the film before the 24 frame screws go in.
How tight should a new FEP film be?
It should ring like a snare drum when you tap it, and it should not be tight enough to tear. The Photonsters FAQ puts factory tension at around 350 Hz and treats anything from 250 to 375 Hz as fine. You can measure that with a phone spectrum-analyser app held close to the film while you tap it with a fingertip.
On a Photon vat the tension comes from geometry, not from adjusting screws. Photonsters explain that the spacer leaves slack in the clamped film, and tightening the module into the vat stretches that slack into approximate tension. Spacer height is therefore your real adjustment: less slack at clamping means a tighter film once installed. If the film sounds dull with every outer screw snug, rebuild it rather than cranking harder. Prusa warns that overtightening makes screws hard to remove at the next change.
How to verify the new film
Run these checks on the bench before any resin goes in.
| Check | Pass | Fail, and the fix |
|---|---|---|
| Visual | Flat, no wrinkles, ring below the vat notch | Wrinkle at a corner: loosen, reseat, retighten diagonally |
| Tap test | Crisp drum note, 250 to 375 Hz | Dull thud: rebuild with less slack |
| IPA test | Paper towel under the vat stays dry | Wet spot: strip, clean the edges, rebuild |
| Resin drip | Drop slides off clean | Smears: protective layer still on |
Then check the build plate. The plate does not move during a film change, but Prusa tells SL1 owners to recalibrate after fitting new FEP. Photonsters list FEP at 127 to 150 microns thick, a spread that matters against a 0.05 mm layer if you switch brands. A quick pass with the paper leveling method costs two minutes.
If you changed film type, such as ACF to FEP on an M5s, print an exposure test first. Anycubic lists different light-transmittance figures for its film types, so settings from one film are not guaranteed on another. The Anycubic exposure settings guide covers reading the calibration print. First-print success means it releases from the film without residue, it stays on the plate, and the LCD is clean when you lift the vat.
What wears out a new film early?
Fast lifts, flat orientations, cured debris, metal tools and resin left sitting in the vat all shorten film life. Anycubic names high print speed, bad orientation and bad resin as the damage causes, and its fixes are to tilt models and reduce Z-lift speed at the cost of print time. Rule out speed and orientation before you blame a resin batch.
Anycubic also recommends cleaning the vat and film after every failed print and before every resin change, because leftover fragments get pressed into the film on the next job. lina makes adds a storage rule: never leave resin in the vat for more than 24 hours. Lift cured patches from the side with a plastic scraper, never a metal blade.
FAQ
how often should you replace fep film
Replace it when it turns cloudy, shows deep scratches or dents, or fails the IPA leak test, not on a fixed calendar. Anycubic rates its Mono X sheet at about 30,000 layers, and the Photonsters FAQ says a well-kept film lasts months. A puncture or tear means immediate replacement, because leaking resin can cure on the LCD.
can i use fep film instead of acf on anycubic
Yes. On the Photon Mono M5s, Anycubic says standard FEP can replace the stock ACF film, but the printer then loses its high-speed printing mode. Expect to use normal-speed profiles and gentler lift speeds after the swap. Buy film cut for your specific vat size, because the ring screw pattern differs between Photon models.
which side of the fep film goes down
Standard FEP is the same material on both faces, so once both protective layers are off, orientation only matters for the metal frames, which fit together one way. ACF is different: Anycubic’s M5s instructions put the matte side of the ACF toward the table during assembly, with the slanted-hole frame facing down.
why is my new fep film leaking
Check the edge before blaming the sheet. The likely causes are cured resin left on the ring or vat lip, a screw hole torn rather than pierced, or screws tightened in a circle instead of diagonally. Prusa’s SL1 guide warns that the edges must be perfectly clean or the tank will leak. Strip it, clean with IPA and rebuild.
Related across the network
- How to Add Supports to Resin Prints: Placement and Settings — resinprintguide.com
- Resin Print Layer Separation: Causes and Fixes — resinprintguide.com
