Use True Cast Resin for precision casting of intricate jewelry and complex engineering components up to 5 mm thick. Pieces printed in True Cast offer exceptional details and smooth surfaces under a wide range of casting workflows and conditions.

Engineered for reliability, quality, and versatility, True Cast Resin integrates into a wide range of burnout schedules. Low thermal expansion, minimal shrinkage, and 0.03% ash content ensure clean burnout and consistently excellent casting outcomes.

True Cast Resin prints at 25 microns and 50 microns. For peer support for printing with this material, join the Formlabs Jewelry/Casting group on Facebook.

True Cast Resin contains wax and solidifies over time at room temperature. This is a normal characteristic for True Cast Resin and not a sign of expired resin.

Formlabs recommends heating the resin in the cartridge on a weekly basis or as needed to prevent the resin from separating. To heat the resin, choose one of the following heating options:

• Place the resin cartridge or bottle in a low heat oven at 45 °C for one hour.
• Place the resin cartridge or bottle in a water-tight bag and submerge in a water bath at 45 °C for one hour.

• Place the resin cartridge or bottle in a resin/filament warmer at 45 °C for 30–60 minutes.
• Third-party resin bottles only: Place the resin bottle in the microwave for 30 seconds.

Once the resin is warm, shake the resin cartridge or bottle vigorously for 30 seconds to fully incorporate the wax into the resin. Warm resin has a low viscosity and may be prone to staining. Handle with care.

Formlabs does not recommend reheating True Cast Resin already present in Formlabs resin tanks. The resin thins and liquifies when the printer heats the resin tank during the preprint process. For third-party resin tanks, users may need to remove True Cast Resin from the tank while not in use to prevent the wax from solidifying.

Casting is both a skill and an art form. The design of the piece to be cast is as important as the material properties for successful results. Pay attention to the design of individual features, the flow of material in the investment, and the printing configuration. Learn more about the best design parameters for common jewelry features, such as prongs, filigree, engraving, surfaces, raised text, and milgrain, in the white paper Jewelry 3D Printing: Basic Design Parameters, Supports, and Orientation [EN] [DE] [FR] [IT] [ZH] from Formlabs.

Print feature recommendations

When printing with True Cast Resin, Formlabs recommends designing models with wall thickness between 500 microns and 5 mm.

When choosing a casting resin, take the casting properties of each material into consideration. For smaller parts or wire filigree, use Castable Wax Resin. For medium to heavy jewelry or small engineering components, use True Cast Resin. For larger investment casting, use Clear Cast Resin.

Avoid investment breakage

Sprues

Print sprues directly on the model to reduce waxing time and reduce the number of supports. During the CAD design phase, add a sprue joining the part to the wax tree with a single point of connection. A self-supporting model with a hollowed-out main tree can fully eliminate the need for additional supports.

Printing with Formlabs printers

Before printing with True Cast Resin, either on a Formlabs printer or a third-party printer, be sure to heat the resin cartridge or resin bottle if it has been sitting at room temperature for more than a week.

Install or update PreForm, then set up the next print job.

To prepare a model for printing in PreForm:

1. Open a model.
2. Select the resin, resin version, and the desired layer thickness.
3. Orient your models.
   • Rings and other similar small parts: Orient vertically to minimize support touchpoints.
   • All other models: Follow Formlabs best practices for orienting parts. Orient the model 30–45 degrees relative to the build platform.
4. Generate supports.
   • Formlabs recommends turning off internal supports on latticed parts, as they may interfere with the lattice structure.
   • Use internal sprues and supports to prevent two thin features from merging and creating wishbones.
   • Make sure any overhangs or joins are sufficiently supported.
5. Send the print job to the printer.

If the resin cartridge has been sitting at room temperature for over a week, warm the resin cartridge and shake to ensure the resin is mixed completely.

Printing with third-party printers

True Cast Resin is compatible with most third-party resin 3D printers. Formlabs recommends using the recommended print settings for third-party printers.

Design self-supporting models that are large enough to fully resolve. Formlabs recommends using spherical support settings on Lychee and Chitubox.

Chitubox

Lychee

Parts printed in True Cast Resin turn a dark purple when rinsed in solvent and lighten to a pale lavender color when dried. The color does not affect the burnout or final casting of the part, but may indicate how clean the part is of solvent. Larger parts with internal cavities may not dry evenly, leaving parts with a marbled color effect.

True Cast Resin color change is not always uniform, especially for thick parts or when parts cannot be dried completely with compressed air. The color change does not affect the castability of the part as long as it is fully cleaned and cured.

The Form Wash and other washing systems agitate the solvent bath and remove parts from the bath after a set time. Wash parts according to the support article for your device. Formlabs recommends removing supports with a high-quality flush cutter to avoid tear-outs after the first wash. Spray or rinse parts with fresh solvent before drying.

If the model is hollow or has internal channels, ensure liquid resin is flushed out thoroughly from these features. Dry the parts thoroughly with compressed or forced air after removing from the solvent bath. Allow parts to fully dry before post-curing.

True Cast Resin does not require post-curing, although Formlabs recommends post-curing to reduce defects during the casting process. Refer to instructions for your particular machine for appropriate recommendations:

• Form Cure (1st Generation) time and temperature settings
• Form Cure (2nd Generation) time and temperature settings
• Form Cure L time and temperature settings

Sand down remaining touch tips with 1000 grit sandpaper after post-curing.

Parts printed in True Cast Resin do not require a specialized burnout schedule. Follow the recommended process for general casting in your desired investment material. Printed parts are shelf-stable and can be cast up to six months after printing without experiencing shrinkage.

For detailed information on casting with Formlabs resins, read the application guide Introduction to casting with Formlabs resins [EN] [DE] [ES] [FR] [IT] [JA] [ZH] and other Formlabs resources. For peer support for printing with this material, join the Formlabs Jewelry/Casting group on Facebook.

Below is a sampling of prints and castings that have worked well for other customers using different printers, investments, burnout schedules, metals, casting machines, and cleanup methods.

• True Cast Resin safety data sheet (SDS)
• Recommended print settings for True Cast Resin on third-party printers
• Introduction to casting with Formlabs resins
• Introduction to Casting for 3D Printed Jewelry Patterns [EN] [DE] [ES] [FR] [IT] [JA] [ZH]
• Jewelry 3D Printing: Basic Design Parameters, Supports, and Orientation [EN] [DE] [FR] [IT] [ZH]