Common Resin Print Failures and How to Fix Them: Supports, Exposure,

Every resin 3D printing beginner eventually experiences the same sinking feeling: you wait four hours for a print to finish, the build plate rises out of the vat, and there is nothing attached to it. You look down into the vat and see a flat pancake of cured resin stuck to the bottom film.

Resin printing is a delicate balance of physics, chemistry, and geometry. When a print fails, there is rarely one single "magic button" to fix it. A failure usually means one of three things went wrong: the exposure time was incorrect, the supports were inadequate, or the orientation created too much suction.

This guide breaks down the most common resin print failures, explains the physics of why they happen, and gives you practical steps to fix them.

Why Resin Prints Fail: The Tug-of-War

To understand failures, you must understand the physics of an MSLA resin printer.

1. The build plate lowers into the liquid resin until it is a fraction of a millimeter away from the clear FEP film at the bottom of the vat.
2. The LCD screen flashes UV light, curing the resin. The resin sticks to the build plate, but it also sticks to the FEP film.
3. The build plate lifts up, peeling the cured layer off the FEP film with a distinct "pop."

Every single layer is a tug-of-war between the build plate and the FEP film. If the FEP film wins, the print fails. Your goal in troubleshooting is to ensure the build plate always wins.

Failure 1: Print Not Sticking to the Build Plate

The Symptom: The build plate is completely empty. The entire print is a flat, cured disc stuck to the FEP film at the bottom of the vat.

The Cause: The first few layers (the "burn-in" or "bottom" layers) did not cure long enough to grip the metal build plate securely, or the build plate is not level.

The Fix:

• Increase Bottom Exposure Time: The first 4 to 8 layers need massive amounts of UV light to bond to the metal. If your normal layer exposure is 2.5 seconds, your bottom exposure should be 25 to 40 seconds.
• Re-level the Build Plate: If the plate is tilted, one side will be too far from the screen to cure properly. Follow your manufacturer's leveling instructions carefully.
• Sand the Build Plate: If the metal plate is too smooth, the resin cannot grip it. Lightly scuffing the plate with 400-grit sandpaper gives the resin microscopic grooves to hold onto.
• Warm the Resin: Cold resin is viscous and cures slowly. Ensure your printing environment is at least 20°C (68°F), ideally 25°C (77°F).

Failure 2: Supports Breaking or "Pancaking"

The Symptom: The raft and the base of the supports are attached to the build plate, but the model itself is missing, or the model looks like a flattened pancake stuck to the FEP film.

The Cause: The supports were too thin or too sparse to handle the peel force. When the build plate lifted, the supports snapped, leaving the model stuck to the FEP.

The Fix:

• Increase Support Density: Add more supports, especially at the lowest points (the "islands") of the model.
• Increase Support Thickness: If printing a large, heavy object, light supports will snap. Use medium or heavy supports for the main structural anchors.
• Check Normal Exposure Time: If your normal layers are under-exposed, the tips of the supports will be too soft and will tear easily. Run an exposure calibration test (like the Cones of Calibration or the XP2 Matrix) to dial in your settings.

Failure 3: The Suction Cup Effect

The Symptom: A hollowed model has a massive blowout, a missing chunk, or severe layer separation halfway up the print.

The Cause: You printed a hollow cup facing the FEP film. As the build plate lifts, it creates a vacuum inside the hollow space. The suction force becomes so massive that it rips the print apart or tears it off the supports.

The Fix:

• Add Drain Holes: If you hollow a model in your slicer, you must punch holes close to the build plate to let air in and liquid resin out. This breaks the vacuum seal.
• Reorient the Model: Tilt the model so that the hollow opening does not form a seal against the FEP film.

Failure 4: Flat Spots and Failed Islands

The Symptom: A miniature's sword is missing its tip, or a character's chin looks flat and melted.

The Cause: "Islands" are parts of the model that begin printing in mid-air (like a downward-pointing sword tip). If an island is not supported, it will cure onto the FEP film and stay there, rather than attaching to the rest of the model.

The Fix:

• Use Island Detection: Most modern slicers (like Lychee or Chitubox) have an "island detector." Run it before slicing to find unsupported pixels.
• Add Manual Supports: Do not rely 100% on auto-supports. Manually place a support directly on the lowest point of the failing geometry.

Failure 5: Warping and Dimensional Inaccuracy

The Symptom: The base of a rectangular box is curved upward at the corners, or parts that should fit together do not.

The Cause: Resin shrinks slightly as it cures. If a large, flat surface is printed parallel to the build plate, the peeling forces and the shrinkage will cause the corners to warp.

The Fix:

• Angle the Print: Never print large flat surfaces parallel to the screen. Angle the model 30 to 45 degrees. This reduces the cross-sectional area of each layer, minimizing peel force and shrinkage.
• Improve Supports: Add heavy supports along the edges of the flat surface to hold it rigid during the printing process.

Failure 6: Hollow Prints Cracking After a Few Weeks

The Symptom: A hollowed print looked perfect when finished, but two weeks later, it split open and leaked liquid resin onto your shelf.

The Cause: Liquid resin was trapped inside the hollow model. Over time, the trapped resin off-gasses, building pressure until the model bursts.

The Fix:

• Thorough Washing: You must flush the inside of hollow models with IPA.
• Internal Curing: UV light does not penetrate deeply. You must shine a small UV LED snake light inside the drain holes to cure the interior walls of the model.

Troubleshooting Checklist

Before you post a picture of a failed print on a forum asking for help, check these variables:

Symptom	What to Check First	Quick Fix
Nothing on build plate	Bottom exposure time & Leveling	Increase bottom exposure by 10s. Re-level plate.
Only supports printed	Support thickness & Normal exposure	Thicken support tips. Run an exposure calibration test.
Print ripped in half	Suction cups & Hollowing	Add large drain holes near the base.
Model is melted/flat in spots	Unsupported islands	Check slicer for islands. Add manual supports.
Print is brittle and yellowed	Post-curing time	Reduce time in UV curing station.

The Golden Rule of Troubleshooting

Change only one variable at a time.

If a print fails, and you simultaneously increase exposure time, change the orientation, add more supports, and heat up the room, you will not know which action actually fixed the problem. If it fails again, you will not know which action made it worse. Be methodical.

Internal Link Suggestions for FilamentMap.com

• Washing and Curing Resin Prints

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