FEP Film Damaged
Elegoo 3D Printer (Resin)
Severity: ModerateWhat Does This Error Mean?
The FEP film is the thin transparent sheet at the bottom of the resin vat. When it is scratched or cloudy, it scatters UV light, causes prints to fail, and can leak. Replace it every 2-5 litres of resin printed.
Affected Models
- Elegoo Mars 4
- Elegoo Mars 3
- Elegoo Saturn 3
- Elegoo Saturn 2
- Elegoo Mars 4 Ultra
Common Causes
- FEP scratched from scraping cured resin off with a metal tool
- FEP cloudy from normal UV exposure over time
- FEP torn from a print failing and curing directly on the film
- Resin residue hardened on the surface
How to Fix It
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Inspect the FEP film by holding it up to a light.
Look for: deep scratches across the print area, a milky haze over most of the film, or any small holes or tears. Minor scratches near edges are OK — scratches in the centre are not.
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Clean minor resin residue with IPA and a soft cloth.
Dampen a lint-free cloth with isopropyl alcohol (90%+) and gently wipe the FEP. Never use metal tools or abrasive cloths on FEP.
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Replace the FEP if it is cloudy, torn, or deeply scratched.
Elegoo sells replacement FEP sheets sized for each model. Third-party FEP (nFEP, rFEP) also works and is cheaper in bulk.
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Install the new FEP with even tension — not too tight, not loose.
A properly tensioned FEP sounds like a low drum tap when you gently press the centre. Too tight causes suction issues. Too loose allows resin pooling.
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After replacing, re-level the build plate.
New FEP has a slightly different thickness. Always re-level after replacing to avoid crashes.
Frequently Asked Questions
How often should I replace the FEP film?
Every 2-5 litres of resin is a common rule of thumb. Visually inspect it every 1-2 litres — replace when you see haze or deep scratches in the print area.
Can I use any FEP film or does it need to be Elegoo brand?
Any FEP film cut to the right size works. Many users prefer nFEP (nano FEP) for better release. Make sure you buy the right size for your specific Mars or Saturn model.