Flame Retardant Resin is a stereolithography (SLA) material for parts that sit near heat, live electronics or ignition sources. It stops burning on its own once the flame is removed, contains no halogens and is rated UL 94 V-0 at 3 mm walls. Parts have the smooth, moulded finish and fine detail of SLA, insulate the electronics they enclose and hold their shape under load near heat. Use it for electronics and battery enclosures, connector housings, aircraft and rail interior prototypes, and fixtures and heater holders.
How Flame Retardant Resin is manufactured
Flame Retardant Resin is manufactured using Stereolithography (SLA) on Formlabs Form 4L printers, where light cures the liquid resin layer by layer through a masked display. Parts are then washed, supports are removed, and every part is post-cured to the Formlabs schedule that develops its full stiffness, strength and heat resistance.
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Upload CAD files to Forge Labs Steam for Flame Retardant Resin pricing and a manufacturability review, and fix issues before production.
SLA delivers the smoothest surface of any 3D printing process. Every part is washed, post-cured and has its supports removed, leaving a smooth, finely detailed surface that is ready to use straight away or to paint.
Parts are washed, post-cured and have their supports removed, leaving the smooth, finely detailed surface SLA is known for. Sharp edges, small text and fine features hold their shape, and the surface is ready for fit checks, assembly and presentation, or as a base for paint.
Painting offers a highly durable, automotive-grade coating that enhances the aesthetics and durability of 3D-printed parts. Each part is hand-finished to ensure smooth surfaces and a premium quality appearance. Using professional-grade coating equipment, this process allows for precise application and exceptional adhesion. Custom color matching is available, making it ideal for applications that require specific branding or visual impact.
Flame Retardant Resin gives engineering teams SLA parts that stop burning when the flame is removed. Enclosures, housings and covers can be printed in a flame-rated UL 94 V-0 material from the first prototype, instead of waiting for cast urethane or moulded parts.
Heat and creep resistance keep housings, brackets and fixtures in shape under load near heaters, motors and other heat sources, and parts sand to a primer-ready surface for painted cosmetic samples.
It completes Forge's flame-rated range. ULTEM 9085 and Antero 800NA FDM meet the full aircraft cabin flame, smoke and toxicity requirements, ULTEM 9085 reaches V-0 at thinner walls, and ULTEM 1010 takes higher heat. Flame Retardant Resin is the choice for smaller, detailed parts that need a smooth moulded finish, crisp features and fast turnaround.
With no tooling or minimum order quantities, one prototype or a production batch prints from the same file.
Electronics & Energy
Flame-rated, insulating charger and battery enclosures with vents and snaps in one piece.
Aerospace & Rail
Interior prototypes, clips and bezels in a resin that passes the FAR 25.853 12-second vertical burn.
Automotive & EV
Connector housings and battery-adjacent parts in a UL 94 V-0 rated material.
Medical Devices
Enclosures for powered medical devices that look and behave like the production part.
Industrial Equipment
Tappable fixtures and heater holders that hold their shape near heat and ignition sources.
Electronics & Energy
Electronics and energy teams use Flame Retardant Resin for charger docks, battery enclosures and power supply housings. Vents, snap features and connector cut-outs print in one piece, and a dielectric strength of 15.1 kV/mm lets housings insulate the electronics they enclose.
Aerospace & Rail
Interior engineers use Flame Retardant Resin for cabin and railcar interior prototypes, fit-check parts, trim clips, bezels and small brackets that need flame performance and a finished surface. At 2.5 mm it passes the FAR 25.853 Appendix F 12-second vertical burn with an average after-flame under one second, and 3 mm parts pass BSS 7239 toxic gas testing. Railcar parts that must meet EN 45545-2 or NFPA 130 move to ULTEM 9085.
Automotive & EV
Automotive and EV teams use Flame Retardant Resin for connector housings, harness clips and parts that sit beside battery packs. Formula SAE rules require UL 94 V-0 materials for parts in contact with the battery pack, and the resin is rated V-0 at 3 mm. SLA detail keeps latches and compliant snap tabs crisp for tight-fitting two-part connector assemblies.
Medical Devices
Medical device teams use Flame Retardant Resin for prototype enclosures and internal housings of powered equipment, so test units look and behave like the production part. IEC 60601-1, the safety standard for powered medical equipment, sets flammability requirements for enclosure materials, so prototype housings enter safety testing in a flame-rated material. The resin has no biocompatibility rating, so it suits housings rather than patient-contact parts.
Industrial Equipment
Manufacturing and maintenance teams use Flame Retardant Resin for jigs, fixtures, heater and fan holders, and replacement parts that sit near heat or ignition sources. It is stiff enough to tap, drill and trim after printing, so fans, sensors and terminals mount with standard screws. With the longer post-cure, its creep resistance at 65 °C under load comes close to Rigid 10K, a glass-filled resin, and strength and stiffness hold through six weeks at 90 °C.
Values from the Formlabs Flame Retardant Resin datasheet for both Formlabs post-cure schedules, tested to the standard listed with each property; liquid resin density from the Formlabs safety data sheet.
Mechanical performance
Tensile and flexural modulus show how stiff the resin is, and elongation shows how far it stretches before it breaks. Flame Retardant Resin is stiffer than Tough 2000, the ABS-like Formlabs resin, while keeping enough stretch for compliant snap tabs and press-in inserts.
Properties are listed for the two Formlabs post-cure schedules. The longer, hotter cure adds stiffness, strength and creep resistance and trades away a little elongation. Notched impact is modest, so generous internal radii keep housings tough at corners and screw bosses.
Material makeup
Part density and hardness describe the finished, post-cured part; liquid density and viscosity describe the resin in the vat. The resin is viscous, so small blind holes and narrow channels need drainage paths to wash cleanly.
Heat performance
Heat deflection is listed at two loads for both cures. The longer cure raises heat deflection and glass transition, so it suits parts that carry load near heat sources, such as fixtures and heater holders.
The UL relative thermal index is the long-term temperature UL assigns for continuous service, while heat deflection describes short-term stiffness under load; match each to how hot and how long the part runs. Thermal expansion is lower after the longer cure, which helps where a part mates with metal.
Functional performance
High dielectric strength and volume resistivity make the resin an insulator for enclosures, connector bodies, bobbins and relay housings. Formlabs measured these values on parts post-cured at 70 °C for 60 minutes.
Compatibility data
Formlabs immersed printed, post-cured cubes in 26 fluids for 24 hours and measured weight gain. Gasoline, diesel, engine and transmission oils, brake fluid, Skydrol 5, hydraulic oil, cleaners and dilute acids and bases leave almost no change, acetone causes the largest gain, and 30% sulfuric acid disintegrated the sample.
Weight gain is screening guidance; confirm long-term or hot exposure with application-specific testing before production release.
Compliance
Each status shows what Formlabs provides: the UL 94 and IEC 60695-11-10 ratings come from a UL Blue Card, and the FAR 25.853, smoke, toxic gas and outgassing results come from independent laboratory reports Formlabs publishes with its datasheet. Formlabs ran the flame, smoke and toxic gas tests on parts post-cured at 70 °C for 60 minutes. Flame ratings depend on wall thickness, so design walls to 3 mm where V-0 is required.
The UL listing's processing conditions name Formlabs Form 3 series printers and the default Form Cure schedule; Forge prints this resin on Formlabs Form 4L printers. Polishing or priming with mineral oil or other flammable lubricants may invalidate the UL rating.
Datasheets, design guidance and supplier documentation for Flame Retardant Resin.
Access the most recent datasheet and supporting documentation maintained by our engineering team.
Flame Retardant Resin datasheetExplore printable geometry recommendations, wall thickness tips, and finishing playbooks for SLA.
View SLA design guideSupplier declarations and test statements for this material.
Flame Retardant Resin is manufactured using industrial-grade Stereolithography (SLA) technology, delivering fine detail and dimensional accuracy for high-detail applications.
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STEP, STL, OBJ, 3MF and IGES supported
