Only the Supports Printed: Resin Model Missing

Likely causes, most common first

1. Too few supports for the part's weightMost common
   Prusa says detachment from supports is normally caused by the object's weight combined with insufficient supports, and that heavy solid parts often fail once they pass a certain weight or height.
2. Supports too thin, or contact points too smallVery common
   Prusa lists supports that are too thin as a main cause of broken supports. Formlabs suggests adjusting the touch point size, the support density, or both when a part detaches from its supports.
3. Areas that start in mid-airCommon
   Prusa points out that parts of an object cannot start mid-air and that the printer has a threshold for overhangs. Unsupported islands print as loose flakes that end up in the vat.
4. Exposure below the resin's recommended valueCommon
   Prusa says that short exposure leaves the resin without enough time to solidify, which gives weak supports and missing details. Use the exposure in the resin maker's profile for your printer rather than shortening it.
5. Solid part with no hollowing or drainageOccasional
   Hollowing reduces weight. Prusa warns that a hollowed part must have drainage holes, because trapped resin can create suction on the bottom of the tank so the part does not release at each layer.
6. Dirty filmLess common
   Prusa says that if the sample also prints with broken supports, debris on the film may be to blame.
7. Faulty display or UV light sourceRare
   Prusa calls a faulty UV LED panel very rare, and suspects the display or light panel only when the sample also prints with parts missing.

Fix it, one change at a time

1. Clear the vat before anything else. With gloves and eye protection, pour the resin through a filter into a separate bottle, recover the fallen part and any flakes, and clean the film as in Resin Print Stuck to the Film. A loose cured piece left in the vat ruins the next print.
2. Print the maker's sample file to split settings from hardware.
3. Reset the slicer to the maker's profile for your resin, including the exposure times. Do not shorten exposure below the resin maker's recommendation.
4. Add supports. Raise support density, add manual supports to every island and to the areas that failed, and increase support thickness or contact point size where the part is heavy.
5. Hollow heavy solid parts in the slicer and add drainage holes. See Hollowing Resin Prints and Drainage Holes.
6. Re-orient the part so fewer features start in mid-air and the heaviest section is close to the platform. See Resin Orientation and Supports.
7. If the sample also fails, inspect and clean the film, and contact the printer maker about the display or light source.

Confirm it is fixed

The same file prints with the model attached to its supports and every feature present. Check the support tips after removal: they should be cured through, not soft or rubbery. Empty the vat afterward and confirm there are no stray cured flakes.

Why it happens

On most resin printers the part hangs upside down from the platform. Every layer, the printer peels the newest layer off the film, and that force pulls on the whole stack: model, supports and raft. The supports are the weakest link. Each one has a small tip where it meets the model, and if all the tips together cannot carry the peel force plus the weight of the part, the model tears away and drops into the vat, leaving the supports standing on the platform.

Weight grows with volume, so a solid part that printed fine at small scale can fail when it is printed larger. Hollowing removes most of that weight, but a hollow part with no drainage hole traps resin and makes a suction cup against the film, which adds to the peel force instead of reducing it.

Exposure matters as much as count. Thin tips that are under-cured are soft, and soft tips stretch and snap. That is why Prusa warns against shortening exposure below the resin maker's recommendation to save time. Find your resin's value with a resin exposure test rather than copying a number from another resin or printer.

Missing arms and thin features are often the same failure on a smaller scale: an island with no support, or a feature hanging on too few tips, prints as a loose flake. The flake usually stays in the vat, and the next print can press it into the film. Clear the vat after every failure, wearing gloves: the flakes and the resin around them are not fully cured. See Resin PPE.