Resin Print Not Sticking to Build Plate: 7 Fixes

The build plate comes up clean, the vat has a rubbery sheet cured onto the film, and several hours are gone. It is common enough that printer vendors publish a dedicated troubleshooting page for this one symptom, and it has a small number of causes that can be worked through in order. Do them in order, because the expensive fixes at the bottom of the list are almost never the answer and the free fixes at the top usually are.

First, read the failure properly

Three different faults get described as “not sticking to the plate” and they point at different things.

A cured sheet welded to the film. The bottom layers exposed, adhered to the release film harder than to the plate, and the plate pulled away without them. This is the classic case and the rest of this article is mostly about it.

Parts floating loose in the vat. The raft or the first supports formed, then the model detached partway up. That is usually suction and support geometry, not plate adhesion.

A partial raft, thinner on one side. The plate is not parallel to the LCD. Go straight to levelling.

Nothing cured at all, film clean. Not an adhesion problem. Check that the vat has resin, that the film is not already punctured, and that the LCD is actually illuminating.

Before touching settings, remove every cured fragment from the vat. A hardened chunk sitting under the plate blocks the light, holds the plate off the film, and guarantees the next attempt fails in the same place for a completely different reason. Prusa’s tank cleaning procedure exists precisely because that residue causes print failures and can damage the display, and it recommends running the clean-up before each print unless the tank was just changed and hand-cleaned. Its method is worth borrowing on any machine: cure a single full-plate layer to capture everything that has sunk to the bottom, then lift the resulting sheet out in one piece. Note the documented limitation, that large debris or a failed print already stuck to the film needs manual cleaning instead.

Fix 1: Level the plate the way the manual says, not the way it looks

Levelling is where the vendor flow starts and it is the cheapest thing to rule out. Elegoo’s guidance for this exact fault leads with checking the official resin settings and then levelling the platform, and it calls out the step people skip: the build platform screws must be loosened before levelling, so the plate can find the LCD plane by itself rather than being held at whatever angle it was last tightened at.

The routine that works: loosen the plate screws, remove the vat, drop the plate to the home position onto a sheet of paper on the screen, apply even downward pressure while tightening the screws in a cross pattern, then re-zero. If your machine has an automatic levelling routine, the same rule applies about clearing debris first.

A plate that is level but not clean fails the same way. Wipe the plate with IPA and let it dry. If the surface is glass-smooth from repeated scraping, a light pass with coarse abrasive across the plate in a cross-hatch gives the first layer something to key into, at the cost of harder part removal.

Fix 2: Increase bottom exposure, and increase it more when it is cold

Bottom layers are a separate setting from normal layers, and they are the setting that determines whether the print starts at all. Elegoo’s guidance is explicit that temperature affects this: as the temperature of the printing environment decreases, increase bottom exposure, and it suggests trying an additional 10 seconds over the recommended parameters as a first move.

Its published starting values for the original Mars give a sense of the range and of how much pigment matters: 5 bottom layers at 90 seconds for maroon and black resin with a 15 second normal exposure, 70 to 75 seconds bottom for translucent at 12 to 15 seconds normal, and 60 to 70 seconds bottom for other colours at 8 to 10 seconds normal. Those numbers belong to an older RGB-panel machine and should not be copied onto a modern monochrome printer, where normal exposures land in the low single digits. The relationship they illustrate is what transfers: bottom exposure is many multiples of normal exposure, and dark pigment needs materially more of it.

Elegoo also notes that the size and weight of the model feed into this, recommending pushing bottom exposure higher still, to 70 or 75 seconds on that platform, for large or heavy models.

The cost of over-doing it is elephant foot, a flared and oversized first few millimetres, and parts fused to the plate hard enough to gouge it on removal. Raise bottom exposure until prints start reliably, then stop.

Fix 3: Get the resin and the room warm

Prusa’s resin documentation recommends storage in the region of 18 to 32 degrees C and warns that cooler conditions alter viscosity and that cold storage encourages gelation. Cold resin is thicker, flows back under the plate more slowly between layers, and cures more slowly for a given exposure. A garage in winter will fail prints that the same machine and the same bottle print perfectly in July.

The fix is the room, not the settings, wherever possible. Heat the space, or enclose the printer, and let the resin come up to temperature in the vat before starting. If you cannot, compensate with exposure as above and accept that the profile is temperature-specific.

Also shake the bottle. Prusa’s instruction is around ten seconds with the lid secured, before every use. Pigment and photoinitiator settle, and resin drawn off the top of a settled bottle behaves like a different product from the same bottle stirred.

Fix 4: Cut the suction force

If the raft forms and the model later detaches, the problem is mechanical. Each layer has to peel off the release film, and peel force scales with the cross-sectional area in contact with it. A large flat area parallel to the plate generates enormous suction.

• Tilt the model 20 to 45 degrees off the plate so no single layer presents a large flat cross-section.
• Hollow the model with 2 to 3 mm walls, and add drain holes large enough to prevent a sealed cup forming a vacuum.
• Slow the lift speed and increase the lift distance so resin has time to flow back into the gap.
• Reduce the plate contact area you are asking to hold: a raft the size of a stamp cannot hold a fist-sized model.

Fix 5: Fix the supports before blaming the plate

Support tips that are too fine shear off under peel load no matter how well the first layer adhered, and the model is found in the vat with its raft still bonded to the plate. Increase tip diameter, add supports to overhanging islands the slicer missed, and make sure the lowest points of the model are supported rather than left to form in mid-air. Tips that are too fat hold fine and leave craters, so this is a trade, not a maximisation.

Fix 6: Inspect and re-tension the release film

Film that has gone cloudy, dimpled, or slack has both lost transmission and gained grip. A dimple is a permanent stress concentration and cured resin keys into it. Hold the vat up to a light: haze, scratches and stretched areas are all replacement conditions. A film with a puncture is an emergency, not a maintenance item, because resin reaching the LCD ends the panel.

Correct tension matters as much as condition. Slack film flexes downward under the plate and changes the effective first-layer gap across the plate.

Fix 7: Confirm normal exposure, then stop guessing

If bottom layers hold and the model still fails partway up, the fault has moved to normal exposure. Underexposed layers delaminate and the part tears itself apart between the peel force below and the cured mass above. Prusa’s resin calibration workflow is the reliable way to settle this: print one object several times at stepped exposures, with the exposure time embedded into each sample, then read the answer off the part. Prusa suggests a 1 second increment on the monochrome SL1S against 3 seconds on the RGB SL1, and its worked example shows geometry failing between 6 and 9 seconds and printing cleanly at 10 to 11.

The full procedure, including how to read the overexposure and underexposure signs and how to handle the bottom layers separately, is in how to calibrate resin exposure time on an MSLA printer. For a starting bracket before you commit that test print, the resin exposure and cure calibrator will generate first-guess values from your LCD type, resin class, layer height and room temperature.

Prevention routine

Filter the resin back into the bottle after a failure, always. Clean the vat before each print. Re-level after any hard plate removal or any crash. Re-check exposure when you change resin brand, colour, or layer height, and again when the seasons change the workshop temperature. Keep a written record of the settings that worked, with the resin name and the ambient temperature next to them.

If you are still assembling the workflow around the printer, the wash, cure, filtering and storage items that make this routine possible are listed in the resin 3D printing starter kit. And if this class of failure is turning into the whole hobby, it is worth reading resin versus FDM honestly before buying a second resin machine to solve it.

See also

• How to calibrate resin exposure time on an MSLA printer
• Resin 3D printing starter kit: what you actually need
• Resin vs FDM 3D printing: which one to buy
• Resin exposure and cure calibrator
• Desktop FDM printing guides
• Slicer profiles and tuning