SLA Resin · Industrial 3D Printing

Flame Retardant Resin

A UL 94 V-0 certified, halogen-free SLA resin for self-extinguishing parts with favorable flame, smoke, and toxicity ratings. Flame Retardant Resin is stiff, creep resistant, and heat resistant, for indoor and industrial environments with ignition sources.

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UL 94 V-0

Flammability Rating

Certified at 3 mm thickness

111 °C

Heat Deflection

@ 0.45 MPa thermal rating

3.1 GPa

Tensile Modulus

Stiff and creep resistant

75 MPa

Flexural Strength

Resists bending loads

Real Flame Retardant Resin Parts

Actual Formlabs SLA prints in Flame Retardant Resin, not renders.

Two-panel photograph of a part printed in Formlabs Flame Retardant Resin held in a torch flame, then self-extinguishing with smoke once the flame is removed — A torch flame applied, then removed: the part self-extinguishes instead of continuing to burn.

Grey electrical connector housings and electronics enclosures printed in Formlabs Flame Retardant Resin — Connector housings and electronics enclosures printed in Flame Retardant Resin.

Summary & Key Takeaways

UL 94 V-0 Certified: Blue Card certified self-extinguishing at 3 mm thickness, and halogen free.
Tested Beyond UL 94: Also tested to FAR 25.853 Appendix F Part I for flammability and ASTM E662 for smoke density.
Stiff and Heat Resistant: A 3.1 GPa tensile modulus and 111 °C heat deflection temperature suit long-term use in warm industrial settings.
Creep Resistant: Holds dimension under sustained load, so brackets and housings stay in tolerance over time.

Compare Flame Retardant Resin to Other 3D Printing Materials

A quick, scannable comparison against the other specialty resins we print. All values are shown at once; use the buttons to focus on one comparison at a time.

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Tensile modulus, flexural strength, elongation at break, impact strength, and heat deflection temperature for Flame Retardant Resin versus Rigid 4000 Resin, High Temp Resin, and ESD Resin.
Property	Flame Retardant	Rigid 4000	High Temp	ESD Resin
Tensile modulus	3.1 GPa	4.1 GPa	2.8 GPa	1.9 GPa
Flexural strength	75 MPa	69 MPa	97 MPa	61 MPa
Elongation at break	7%	5.3%	2%	12%
Notched Izod impact	22 J/m	23 J/m	17 J/m	26 J/m
Heat deflection temp (0.45 MPa)	111 °C	77 °C	238 °C	62 °C
Support structures	Removable supports for overhangs	Removable supports for overhangs	Removable supports for overhangs	Removable supports for overhangs

Why Choose Flame Retardant Resin?

A specialty material for the cases where a flammability certification, not a mechanical property, decides what you can ship.

Self-Extinguishing, Halogen Free

UL 94 Blue Card certification at V-0 for 3 mm thickness, achieved without halogenated flame retardants, so parts can go into enclosures and cabinets where a burning-drip rating governs approval.

FST Ratings for Transport

Tested to FAR 25.853 Appendix F Part I for flammability and ASTM E662 for smoke density, the tests that aerospace and rail interiors are assessed against. Full results are in the technical data sheet.

Stiff and Stable Long Term

A 3.1 GPa tensile modulus with a 111 °C heat deflection temperature and creep resistance keeps brackets, mounts, and housings dimensionally stable through extended service in warm environments.

Flame Retardant Resin Design Rules (DFM) at a Glance

Formlabs SLA design guidelines for Form 3 and Form 4 generation printers. Check your CAD feature dimensions against these limits before uploading your file.

Min. wall thickness (supported)	1.0 mm
Min. wall thickness (unsupported)	1.0 mm
Min. embossed detail	0.1 mm
Min. engraved detail (width & depth)	0.15 mm
Min. hole diameter	0.5 mm
Min. drain hole diameter	2.5 mm
Clearance between separate or moving parts	0.5 mm min
Max. unsupported overhang	5.0 mm · 10° min. angle from level
Max. single-part build size	353 × 196 × 350 mm

Hand assembling a grey enclosure printed in Formlabs Flame Retardant Resin around a cooling fan, with a screwdriver — Assembling a printed enclosure around a fan. Walls that must carry the V-0 rating need to be 3 mm or thicker.

Source: Formlabs SLA design specifications for Form 3 / Form 4 generation printers, adapted to hold walls to a higher minimum than Formlabs' published figures. The UL 94 V-0 certification is tested at 3 mm thickness, so any wall that has to carry the flammability rating must be designed at 3 mm or thicker; the minimums below cover printability, not certification. These are general guidelines; cross-section, hole depth, and part geometry can shift the safe minimums for a specific design. Maximum build size reflects our largest-format SLA printer; actual build size depends on which machine your order routes to.

Frequently Asked Questions

Everything you need to know about designing, ordering, and using Flame Retardant Resin parts on Form Now.

What is Flame Retardant Resin?

Flame Retardant Resin is a specialty stereolithography (SLA) resin from Formlabs that is UL 94 Blue Card certified for creating self-extinguishing, halogen-free parts with favorable flame, smoke, and toxicity ratings. It is stiff, heat resistant, and creep resistant for long-term use in indoor and industrial environments with high temperatures or ignition sources.

What flammability certifications does Flame Retardant Resin hold?

Flame Retardant Resin is UL 94 V-0 certified at 3 mm thickness. It has also been tested to FAR 25.853 Appendix F Part I for flammability and ASTM E662 for smoke density. For the full test results and certifications, see the Formlabs technical data sheet.

How thick does a wall need to be for the UL 94 V-0 rating to apply?

The UL 94 V-0 certification is tested at 3 mm thickness, so a wall must be at least 3 mm thick for the rating to apply to it. The general minimum wall thickness for printability is lower than that, so design any feature that has to carry the flammability rating to 3 mm or greater.

What is Flame Retardant Resin used for?

Flame Retardant Resin is commonly used for aerospace components, electronics enclosures, transportation parts, and industrial jigs, that is, parts that operate near ignition sources or in cabinets and interiors where a flammability rating is required.

How stiff and heat resistant is Flame Retardant Resin?

Flame Retardant Resin has a tensile modulus of 3.1 GPa, a flexural strength of 75 MPa, and a heat deflection temperature of 111 °C at 0.45 MPa, with 7% elongation at break. It is a stiff, creep-resistant material rather than a ductile one, so it is not suited to snap fits or parts that must flex.

What are the minimum wall thickness and hole size design rules for Flame Retardant Resin?

Per Formlabs' SLA design specifications for Form 3 and Form 4 generation printers, we recommend a minimum wall thickness of 1.0 mm for both supported and unsupported walls, and holes should be at least 0.5 mm in diameter. Note that these are printability minimums; walls that must carry the UL 94 V-0 rating need to be at least 3 mm thick. Maximum single-part build size is 353 x 196 x 350 mm.