Anycubic Photon Mono Resin Sticking to FEP: Causes and Fixes

Anycubic Photon Mono resin sticking to FEP is one complaint with three different signatures, and the fix depends on which one is in the vat. A cured disc on the film under a bare build plate is a first-layer problem: leveling, bottom exposure, or cold resin. A print that grew for an hour and then tore off partway up is a peel-force problem: suction, lift speed, or a tired film. A faint skin of cured resin left on the FEP after an otherwise good print is wear. Sort the failure first, because the setting that fixes one of these makes another worse.

Read the failure before changing a setting

Look at the vat before cleaning it.

Bare plate, full-footprint disc on the FEP. A disc thicker on one side means the plate is not parallel to the screen. An even disc points at exposure or temperature.

Partial print on the plate, torn section on the film. A wide flat area or a closed cavity at the break height means peel force exceeded the layer bond.

Print finished, film holds a ghost of it. Clouded or worn film. Replace it.

Cause 1: the plate is not parallel to the LCD

The community-maintained Photonsters FAQ calls incorrect build-plate tramming “the number one reason for print failures”. The Mono’s procedure is in the user manual: leveling paper on the curing screen, Tools then Move to lower the Z axis until it stops, press the platform flat, tighten the four platform screws. Resione’s adhesion guide adds the detail that matters: tighten in diagonal order so the last screw does not tilt the plate. What that sheet of paper is actually measuring is covered in the paper leveling method on Anycubic machines.

Cause 2: bottom exposure and bottom layer count

The Mono manual’s recommended parameters for Anycubic resin at 0.05 mm are: normal exposure 2 s, off time 0.5 s, bottom exposure 45 s, 6 bottom layers, Z lift distance 6 mm, Z lift speed 4 mm/s, Z retract speed 6 mm/s. Note the ratio. Forty-five seconds is more than 20 times the normal exposure; AmeraLabs’ settings guide recommends 5 to 8 times normal for monochrome LCDs and 4 to 6 bottom layers at 50 µm. The default is already generous. If the plate is level and the print still fails at 45 s, adding exposure is treating the wrong cause.

When it is the cause, the vendor numbers are: Anycubic’s troubleshooting page says increase bottom exposure by 10 s and add 5 bottom layers; Resione says double it, with a ceiling of 100 s. Treat these as a diagnostic step, not a profile. Long bottom exposure flares the first layers outward (elephant foot) and fuses support bases into a slab. The UVtools calibration tools include an elephant-foot test that measures exactly this.

Third-party resin changes all of this: bottom exposure scales with the resin’s own normal exposure, and dark pigments need more. Run a stepped test on the bottle, following how to calibrate resin exposure time on an MSLA printer; the differences between families are in Anycubic resin types compared.

Cause 3: cold resin

Anycubic’s resin settings page states that below 68 °F / 20 °C, exposure should go up 30% and Z lift speed down 30%. On the Mono defaults: normal 2 s to 2.6 s, bottom 45 s to about 58 s, lift 4 mm/s to 2.8 mm/s. Cold resin is thicker, flows back under the plate more slowly, and peels harder. An unheated garage in winter produces the even-thickness disc on a machine that ran all summer with nothing changed.

Cause 4: peel force higher than the layer bond

Every layer on a bottom-up MSLA printer is a peel. When the peel force exceeds the bond between the fresh layer and the one above it, the print tears and the torn piece stays on the film. Four things drive it.

Lift speed. Anycubic lists excessive lift speed as a cause and its FEP-care page recommends reducing it to lower peel force. The Mono default of 4 mm/s is 240 mm/min. AmeraLabs’ beginner values are 40 to 60 mm/min for normal layers and 5 mm/min for bottom layers, with a 0.5 to 1 s rest after retract. Dropping into that range costs print time and removes the variable; speed back up once the part prints.

Lift distance. Anycubic recommends increasing it so the layer fully separates before the plate returns. The default is 6 mm; AmeraLabs suggests 7 mm for normal layers and 10 mm for bottom layers.

Cross-sectional area. A flat face parallel to the plate is one enormous layer with one enormous peel. Anycubic’s FEP page recommends tilting the model for this reason.

Suction. A hollowed model with no holes forms a cup. The Photonsters FAQ is blunt that vent holes are “improperly called ‘drain’ holes”: their job is to let air and resin move during the lift so the cavity does not pull a vacuum against the film. Two holes, not one, so air can enter as resin leaves. A print that tears at exactly the height where a cavity closes has this cause and no other.

Cause 5: the film itself

Loose. Anycubic’s fix is to tighten the screws on the back of the vat frame until tapping the film gives a drum-like sound; Resione’s version is to flick it and listen for a crisp note. A dull thud means the film deflects under the plate and the first layer is thicker than the slicer thinks.

New film with the protective plastic still on. The Photonsters test: drip a few drops of resin on the film and hold it vertical. Clean run-off means bare FEP; sticking and smearing means a protective layer still to peel.

Worn. Anycubic lists three replacement triggers: a cloudy surface, deep scratches or indentations, and punctures. Pour isopropyl alcohol into the empty vat; a leak means a hole.

Replacing it. Anycubic’s FEP tutorial is shot on the larger Mono X vat, but the sequence transfers: corner screws first, then the rest progressively; back screws loose until the film is seated, then adjusted last for tension; a bottle cap about 13 mm high as a spacer for the film’s slight protrusion; no wrinkles.

Getting the cured disc off the film

Push up from underneath with a gloved fingertip until a corner lifts, then work a plastic scraper in from the side. Never a metal blade. Anycubic’s guidance is to clean the vat and film after every failed print; filter the resin in the same session, because fragments otherwise end up under the next print. The general version of the first-layer failure, on any MSLA machine, is in resin print not sticking to the build plate.

Settings to change, in order

For a Photon Mono with Anycubic resin at 0.05 mm, from the manual’s defaults:

Symptom	Change	From, to
Disc on FEP, thicker one side	Re-level, diagonal screw order	n/a
Disc on FEP, even thickness	Bottom exposure +10 s, bottom layers +5	45 s, 6 layers to 55 s, 11 layers
Room below 20 °C	Exposure +30%, lift speed -30%	2 s to 2.6 s; 45 s to 58 s; 4 mm/s to 2.8 mm/s
Torn mid-print at a wide layer	Lift speed down, lift distance up, tilt the model	240 mm/min to 40 to 60 mm/min; 6 mm to 7 mm
Torn where a cavity closes	Add two vent holes	n/a
Film dull on flick	Tension the vat screws	drum sound
Film cloudy or leaks IPA	Replace FEP	n/a

How to verify

Print the UVtools elephant-foot test, or any small flat plate of known width, at the new settings. Pass criteria: the print needs a scraper to come off the plate, the FEP is clear when held to the light, and the base measures close to nominal with calipers rather than flaring. If it flares, bring bottom exposure back down in 5 s steps. Then print the same file again: a fix that holds for two consecutive prints on a clean film is a fix; one success after a vat cleaning is a coincidence.

Related across the network

• Resin Print Layer Separation Causes: Under-Exposure, Cold Resin, Peel Force and Four Others, in Test Order — resinprintguide.com
• Resin Print Not Sticking to Build Plate: 7 Fixes — resinprintguide.com
• Best Resin 3D Printer for Miniatures: Pixel Size, Tilt Vats and Five Picks by Budget — resinprintguide.com
• How to Calibrate Resin Exposure Time on an MSLA Printer — resinprintguide.com
• Resin 3D Printing Starter Kit: What You Actually Need — resinprintguide.com

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