Resin printing troubleshooting: adhesion, FEP film, layer separation, holes

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A resin print rarely fails quietly. Sometimes only a thin skin is left in the vat after hours, sometimes half the model hangs on the film, sometimes it tears between two layers. Most failures have only a few causes: exposure, levelling, temperature, supports and the condition of the vat and film. This page goes through the typical failure patterns one by one. How a resin printer works in general is explained under Resin printing explained.

Wear nitrile gloves and safety glasses whenever you troubleshoot. Failed prints almost always mean liquid resin on the build plate, vat and tools, see Safety in resin printing.

Clean up first, then search

After every failed print: before you start again, the vat must be clean. Cured residue in the resin or on the film is pushed against the build plate in the next print and can damage the film or the display. Anycubic describes these steps:

1. Check the build plate and remove cured residue. A metal scraper may be used on the build plate.
2. Use the printer’s cleaning function, if it has one. It exposes a thin layer to which loose residue sticks.
3. Loosen cured resin in the vat only with a plastic scraper, never with metal.
4. Stir the resin with a plastic spatula and pour it back into the bottle through a filter.
5. Check the empty film: if it has dents, scratches or baked-on residue, Anycubic advises replacing it.

Depending on the machine, the film is called FEP, nFEP, PFA or ACF. For troubleshooting this makes no difference, they are all wear parts.

Print does not stick to the build plate

What it looks like: The build plate comes out empty, a cured sheet floats in the vat, or the model comes loose in the middle of the print.

The bottom exposure depends heavily on the machine, the resin and even the colour. For the original Mars, for example, Elegoo gave 60 to 70 seconds for most colours, 70 to 75 seconds for transparent resin and 90 seconds for black and dark red resin, and more for large and heavy models. Current machines with a stronger light source use very different values. Always take the resin manufacturer’s table for your machine as a starting point.

Print stays stuck to the film

What it looks like: Part of the model or the whole base sticks to the bottom of the vat, with only the rest hanging on the build plate.

At its core this is the same problem as above: adhesion to the film is stronger than adhesion to the build plate. The causes therefore overlap. Check first: levelling, bottom exposure, temperature. Elegoo names exactly these three points for the failure pattern “model sticks to the film instead of the build plate”.

Then there is the suction cup effect: hollow or shell-shaped parts whose opening faces the film trap air. Lifting creates negative pressure. Formlabs describes the consequences: holes or torn walls in the part, rough surfaces inside the shell and resin splashes in the printer when the suction cup breaks away from the film. The fix according to Formlabs: add drain holes and orient the model so that no shell faces the film.

If a residue stays on the film, remove it as described above before the next print starts.

Layers separate

What it looks like: The model is split in itself, layers can be lifted off like pages, or there is a clean crack right across the part.

Phrozen names four causes:

• Normal layers exposed too briefly: They do not bond firmly enough. Increase the exposure time of the normal layers.
• Bottom layers exposed too long: Very hard bottom layers create stress in the rest of the part. Reduce the bottom exposure carefully, but not so far that adhesion suffers.
• Lift speed too high, wait time too short: The resin has no time to flow under the build plate. Lift more slowly and extend the wait time before exposure.
• Dirty vat or film: Cured residue or a cloudy, scratched film disturbs every layer at the same spot.

Anycubic also points out: if only the base hangs on the build plate and the rest is missing, the normal exposure is too low.

Holes and missing parts

What it looks like: Individual spots are missing, walls have holes, thin parts such as swords or antennae have broken off or were not printed at all.

A large, ragged hole in a shell wall is usually the suction cup effect from the previous section.

Supports break or the model tips over

What it looks like: Overhangs are missing, the model hangs crooked on a few supports or has fallen into the vat in the middle of the print.

According to Phrozen, the most common cause is simply too few or too thin supports. Then there are supports in the wrong place, meaning large areas without support, and unsuitable settings such as support tips that are too small. What helps:

• increase the density and thickness of the supports, especially for heavy models
• support critical areas such as overhangs and large surfaces by hand
• change the tip size or support type if supports tear off one after another
• avoid cold resin, which according to Phrozen is thicker and adheres less well

How supports work in general is explained under Supports. That article refers to FDM, but the reasons why overhangs need support apply just the same.

Cold: the underestimated cause

Many failed prints in autumn and winter have the same cause: the resin is too cold. Cold resin flows less well, the layers become uneven and adhesion suffers. Anycubic writes that flowability decreases below 20 °C and recommends using the vat heating where available. The manufacturers’ temperature recommendations are compared under Resin types.

What helps:

• Heat the room: The printer should not stand in a cold cellar or garage.
• Vat or chamber heating: Machines such as the Elegoo Saturn 4 Ultra 16K heat the vat to 30 °C according to the manufacturer, the Anycubic Photon P1 adjustable from 20 to 40 °C. Anycubic points out that the vat can be hot after long heating.
• Preheat the resin: Anycubic lists preheating the resin before printing as an option.
• Adjust the exposure: In a cool environment Elegoo advises about 10 seconds more bottom exposure.

Exposure test: finding the right time

The exposure time is the most important value in resin printing. Too short, and details, supports and adhesion are missing. Too long, and details fill in, holes close up and the surface becomes rough according to Phrozen. Instead of guessing, you print a test.

Check the display first. If nothing works any more, the LCD may also be defective. Anycubic describes a simple test: take out the vat and build plate, lay a white sheet of paper on the display and start the exposure test in the menu. The image on the paper must match the image on the control panel. If areas are missing, it is a case for support. Do not look directly into the light.

Then test the exposure. Anycubic supplies the test file R_E_R_F for this. It prints several identical test models side by side, each with a different exposure time. Anycubic explains the evaluation like this:

• A model with more open holes shows details more completely but is more prone to failed prints.
• A model with more successfully printed thin pillars prints more reliably but loses some detail.
• Also compare bridges and fine pillars and choose the time according to what matters more to you.

Other manufacturers offer their own test files, and many resin manufacturers give starting values for common printers. What matters: test every new resin and every new colour once, even from the same manufacturer.

Resin slicers: what is available

The slicer places supports, hollows out, adds drain holes and sets the exposure values. The manufacturer states which programs your printer supports. Examples from our overview of resin printers:

• Chitubox: Widely used and compatible with many printers. There is a free basic version and a paid Pro version with more repair, editing and measuring tools (according to 3Dnatives).
• Lychee Slicer: Also available as a free version and as paid versions with extra features (according to 3Dnatives).
• Manufacturer slicers: Photon Workshop from Anycubic, ELEGOO SatelLite, HALOT BOX from Creality and PreForm from Formlabs are tuned to the manufacturers’ own machines. According to Formlabs, PreForm is completely free, with no licence fees.

For troubleshooting it is worth a look in the slicer before a drop of resin is used: are there enough supports on the overhangs, do hollow parts have drain holes? According to Formlabs, PreForm marks suction cup areas with the “Show Cups” function. Prices and feature sets of the paid versions change often, so check them on the provider’s site before buying.

In short

• After every failed print, empty the vat, filter the resin and check the film.
• Adhesion to the build plate or film: levelling, bottom exposure, temperature.
• Layer separation: exposure of the normal layers, lift speed, wait time, clean film.
• Holes: exposure, wall thickness, air bubbles, drain holes.
• Below 20 °C it gets difficult. Heat the room or vat.
• Calibrate every new resin once with an exposure test.

Continue with: Washing and curing and Resin types.

Sources

As of 10/2026.

• Anycubic Wiki: Model does not stick to the build plate (Photon P1 Max) (levelling, exposure test, R_E_R_F, 80 s bottom exposure, below 20 °C)
• Anycubic Wiki: Residue detected, CODE 305 (cleaning, filtering, checking the film)
• Elegoo: Model sticks to the film instead of the build plate (levelling, temperature, bottom exposure)
• Phrozen: How to Identify and Fix Resin Print Failures (adhesion, layer separation, supports, surfaces, holes)
• Formlabs Support: Cupping blowout (suction cup effect)
• Formlabs: PreForm
• 3Dnatives: Slicer-Software ChiTuBox and Lychee Slicer
• Manufacturer information on vat heating and slicers: data sheets in our overview of resin printers