Silicone 40A Resin is a pure silicone without added monomer or acrylate, which combines the material properties of cast silicone with the benefits of 3D printing. Printing with Silicone 40A Resin eliminates the need for tooling and labor-intensive casting processes, enabling you to produce custom silicone parts with isotropic properties and complex geometries that aren’t possible with casting or molding.

Sometimes prints don't come out as expected. Compare symptoms of common issues with parts printed in Silicone 40A Resin to narrow in on the underlying source of the problem and find a solution.

“Non-adherence” describes a print defect in which prints are either partially or completely detached from the build platform. This occurs when the initial layers of a print fail to adhere to the build platform. In cases of complete non-adherence, the print is missing from the build platform and there is a flat area of cured resin on the bottom of the resin tank.

To resolve non-adherence issues when printing with Silicone 40A Resin:

• Make sure you are using a dedicated build platform and resin tank for printing with Silicone 40A Resin. For best results, do not reuse a build platform or resin tank that has previously been used with another resin type.
• Calibrate your printer’s Z-axis.
• Follow general Formlabs guidelines for non-adherence.
• Adjust the edge profile of your model. Models with no radius or a small radius around their base print more reliably than those with a larger radius.

Parts that adhere to the build platform properly can also fail by separating from or falling off their supports later during the print. This can be due to insufficient supports, part geometry, or the age of the resin.

To prevent parts from falling off their supports during the print:

• Manually add supports in PreForm if necessary.
• Ensure that support tips are the proper size. Larger touchpoints generally hold the part better but leave larger marks or nubs during post-processing.
• Reorient your model so that larger layers print closer to the build platform. Parts are more likely to separate from their supports when their cross-sectional area increases over the course of the print.

“Delamination” describes a print defect in which the cured layers of a print separate from one another. Delamination can occur on any type of 3D printer, though the causes are unique to each print process.

To resolve delamination issues when printing with Silicone 40A Resin:

• Reorient your models to reduce the aspect ratio of their height relative to their footprint on the build platform. Tall and high aspect ratio parts may shift during the print if the structure is not sufficiently rigid, leading to delamination.
• Make sure that overhangs, whether supported or unsupported, are oriented closest to the build platform, even if that leads to cupping. Overhangs positioned far from the build platform may shift during the print, leading to delamination.

Like with other soft Formlabs materials, such as Flexible 80A Resin and Elastic 50A Resin, tall, narrow parts printed in Silicone 40A Resin are susceptible to failure if they are not rigid enough to resist normal printing forces. In some cases, the print might finish successfully, but your printed parts may exhibit waviness or other dimensional accuracy issues.

To prevent waviness or other similar print defects when printing with Silicone 40A Resin:

• Manually add supports in PreForm if necessary.
• Ensure that support tips are the proper size. Larger touchpoints generally hold the part better but leave larger marks or nubs during post-processing.
• Reorient your models to reduce the aspect ratio of their height relative to their footprint on the build platform. Parts taller than 12 cm may buckle and shift during printing, leading to waviness or other layer registration symptoms even if the print finishes successfully.