“Cupping” is a concern unique to upside-down stereolithography (SLA) printing. A print failure caused by unresolved cupping is often referred to as a “blowout.” This occurs when a hollow or convex portion of a part acts as a suction cup and traps air while printing. As the build platform pulls away from the tank during the peel process, the empty space within the cup increases. This reduces the air pressure within the cup to create a pressure differential that pushes inward on the surrounding cup walls. If the walls are too thin and unable to withstand the pressure, then they buckle inward to equalize the pressure. Depending on the location of the rupture, the part can potentially continue to print without further errors.

The risk of a blowout is dependent on the resin type, size of the cup, shape of the model, and thickness of the cup wall. Small cups, or cups with thicker walls, may print successfully. Formlabs recommends adding a drainage hole and orienting the model in PreForm to minimize cupping.

• A “hole” in the wall of your part
• A large, ragged “rupture” in your part
• Poor surface finish on cup surfaces
• Resin splashing within printer when suction cup separates from resin tank

Any of the following factors, or a combination of them, can cause cupping blowout in prints:

• No drainage holes in hollow or convex parts
• Model orientation issues
• Model printed without resolving cups highlighted in PreForm

Enable Show Cups and inspect the model with the Slicer tool, or add a drainage hole to the cup in your preferred 3D design package before returning the model to PreForm.

If the troubleshooting steps above do not resolve the print failure, contact Formlabs Support or your authorized reseller.

To help us provide the fastest and most effective response to your issue, please follow these steps:

1. Upload diagnostic logs
   • On a Form 2
   • On a Form 3/Form 3B
   • On a Form 3L/Form 3BL
2. Serial name of the printer
   • The serial name is on the back panel of the printer in the format AdjectiveAnimal.
   • On a Form 2: Tap the printer icon on the home screen. The Your Printer screen appears.
   • On a Formlabs LFS printer (Form 3 or later): Tap the printer icon on the Home screen.
3. Troubleshooting steps attempted
   • Example: “I reoriented the model in PreForm. I inspected the resin tank and did not notice any damage, clouding, or debris.”
4. Resin formulation and lot number
   • The lot number is inside the skirt of the resin cartridge.
5. Layer thickness
   • On a Form 2: Tap the queue icon on the home screen. The Jobs screen appears.
   • On a Formlabs LFS printer (Form 3 or later): Tap Queue on the Home screen.
6. Relevant FORM files
   • If available, attach FORM files of the model to the support request.
7. Previous attempts to print the part and any successful prints
   • Example: “I printed the file part2.form three times previously. The first and second were successful. The third one failed.”