Silicone 3D Printing for Durable Parts with Formlabs 3D Printers

By TriMech Marketing, last updated June 10, 2024

Table of Contents

    Introducing Silicone 40A Resin, the first accessible 100% silicone 3D printing resin. Eliminate molding and labor-intensive casting processes: Silicone 40A Resin uses Formlabs’ patent-pending Pure Silicone Technology™  to 3D print pure silicone parts in-house, in a matter of hours.

    With this 40A Shore durometer material, you can fabricate soft, pliable, and durable parts with a 230% elongation at break and a 12 kN/m tear strength that can withstand repeated cycles of stretching, flexing, and compression. Combine the high performance of silicone and the design freedom of 3D printing to create highly functional silicone parts with excellent chemical and thermal resistance (-25°C to 125°C), fine features as small as 0.3 mm, and complex geometries that are not possible with traditional methods.

    3D Printer compatibility: Formlabs Form 4, Form 4B, Form 3+ and Form 3B+.

    Silicone 3D Printing with Formlabs

    Whether you are looking to fabricate functional prototypes, beta and validation units, flexible fixtures and molds, or low-volume production of end-use parts, Formlabs Silicone 40A Resin allows you to create high-performance silicone parts on demand, without the design constraints, lead time, and costs of casting or molding.

    • Soft and Pliable: Choose Silicone 40A Resin to fabricate soft parts with excellent elasticity.
      • 40A Shore Durometer
      • Rebound Resilience: 34 %
    • Extremely Durable: Parts printed with Silicone 40A Resin can withstand repeated cycles of stretching, flexing, and compression without tearing, just like cast silicone parts.
      • Tear Strength: 12 kN/m
      • Elongation at Break: 230 %
      • Ross Flex > 500,000 Cycles
    • Design Freedom: Benefit from the flexibility of 3D printing to expand design complexity and unlock customization.
      • Minimum Negative Feature Size: 0.3 mm
      • Minimum Positive Feature Size: 0.5 mm
    • Temperature and Chemical Resistant: Build watertight and chemical-resistant parts that can operate in high temperatures. For in-field testing, urethane or epoxy casting, and even end-use parts production, our material can undergo the most demanding environments.
      • Temperature Range: -25 °C to 125 °C
      • Glass Transition Temperature: -107 °C
    Silicone 40a resin example parts

    Silicone 40A resin example parts

    Silicone 40A Resin FAQs

    Is it really 100% silicone? How can you 3D print 100% silicone?

    There isn’t any monomer or acrylate in the formulation. Silicone 40A Resin cures with UV, using Formlabs patent-pending Pure Silicone Technology, similar to how cast silicones use catalysts to cure. The composition is similar to cast silicone.

    What are some key design features to consider

    We can print Silicone 40A Resin parts with a minimum negative feature size of 0.3mm and a minimum positive feature size of 0.5mm Avoid geometries with unsupported walls thinner than 0.7 mm. For more details please refer to Silicone 40A Resin Usage Guide.

    What additional equipment is required to print with this resin?

    Silicone 40A Resin uses the standard Form 3+ printing workflow and doesn’t require any additional equipment. Formlabs recommends using a dedicated Form 3 standard Build Platform. Silicone 40A Resin post-processing workflow requires a different wash solvent blend made of IPA and n-Butyl Acetate (4:1 by volume) and a glass beaker to post-cure the parts.

    Why does Silicone 40A Resin require a separate wash solvent?

    Formlabs tested different wash solvents and found that the solvent blend of IPA and n-butylacetate (4:1 by volume) has the best performance in removing the surface tack of Silicone 40A Resin parts.

    Why do post-cured parts printed with this resin have an odor? How can I minimize it?

    Some components in Silicone 40A Resin parts emit an odor during the post-curing step. However, the odor of silicone parts dissipates with time when parts are left exposed to air. You can also mask the odor with a fragrance such as Febreze HD. N-butyl acetate, which is one of the components of the solvent blend used to wash silicone parts, has a strong fruity smell. To keep the odor to a minimum, we recommend keeping the Form Wash closed when not in use.

    Are there any health risks related to the odor of the resin? Does it require specific ventilation?

    There are less volatiles in silicone than in Formlabs Standard resins, our noses are just more sensitive to it. There is no need to update the ventilation requirements from the regular Form 3 workflow unless the user wants to reduce the odor.

    Are Silicone 40A Resin parts UV resistant?

    Under high humidity and UV exposure, Silicone 40A Resin parts show some degradation in mechanical properties. We recommend not storing Silicone 40A Resin parts in sunlight, high humidity environments, or in closed containers under direct sunlight which can lead to faster degradation of properties.

    What is Silicone 40A Resin’s biocompatibility status?

    Silicone 40A Resin has passed our internal testing for in-vitro cytotoxicity, irritant, and skin sensitization. The certifications are pending for ISO-10993-5 and ISO-10993-10 which will make this resin suitable for long-term skin-safe and short-term mucosal applications.

    Is this resin food-safe?

    Parts made with Silicone 40A Resin are not food-safe.

    Can I apply paint, coating, or other post-processing methods to this resin?

    Formlabs have tested a few silicone adhesives that work well with Silicone 40A Resin parts. Other than this Formlabs have not extensively tested applying other media such as coatings or paints to the printed silicone parts and Formlabs leave this to the user to experiment with their applications.

    How does this material compare to other Formlabs flexible materials?

    • Silicone 40A Resin is a pure silicone material, while Elastic 50A Resin and Flexible 80A Resin are silicone-like materials. Silicone 40A Resin parts have much higher durability, elasticity, chemical resistance, and thermal stability. It is better suited for in-field prototypes and end-use parts.
    • Silicone 40A Resin is softer than Elastic 50A Resin and Flexible 80A Resin.
    • Silicone 40A Resin is dark, while Elastic 50A Resin and Flexible 80A Resin are transparent.
    • Silicone 40A Resin post-processing workflow differs slightly from the regular Form 3 workflow.
    • Elastic 50A Resin and Flexible 80A Resin have a lower entry price and

    How does this material compare to cast silicone?

    The workflow to create 3D printed Silicone 40A Resin parts is simpler and faster compared to making cast silicone parts. Additionally, 3D printed Silicone 40A Resin has similar material properties to cast silicone. However, 3D printed Silicone 40A Resin parts have an odor after post-curing that dissipates with time, a slightly lower thermal resistance (-25 0C to +125 0C), and lower long-term humidity and UV stability.