Flame Retardant 3D Printed Plastics

Underwriters Laboratories' guidelines for flammability (UL 94) outline specific test methods and classifications based on flame testing results. UL94 V-0 is the highest rating, indicating that a product quickly self-extinguishes without flaming drips. UL94 HB is the lowest flammability rating, where the material will not necessarily self-extinguish but burns slowly (e.g., less than 40 mm/min). Parts that meet UL flammability standards may also meet FAR 25.853, the Federal Aviation Administration (FAA) criteria for cabin and cargo materials. FAR 25.853 60-second test includes 60 seconds of burn exposure, where the specimen may not burn for more than 15 seconds after the flame, and any drips of material will burn for less than 3 seconds. During the FAR 25.853 60-second test, no more than six inches of the material specimen should burn to pass. Both tests are valid for classifying flame-retardant materials, but the FAR qualification helps streamline the selection of suitable materials for aerospace and aviation applications.

49 CFR 571.302, also known as FMVSS 302, is a vehicle safety standard test that evaluates the burn resistance of materials used in the occupant compartments of motor vehicles. The standard typically applies to passenger cars, multipurpose passenger vehicles, buses, and trucks.

Many of our materials used in the HP Multi Jet Fusion 3D printing process have passed this testing standard. You can read more about the specifics of the materials and test in the document linked here. Below, you will find a table summarizing which materials pass FMVSS 302 and links to their data sheets to learn more.

UL94 HB is the least flame-retardant of the UL94 classifications. Instead of subjecting the sample to a vertical burn, such as with UL94 V classifications, it's subjected to a flame in a horizontal position. It passes the test if the material burns at a rate less than a specified maximum or self-extinguishes. Due to the less stringent criteria for this rating, we have many 3D-printed materials that comply with the UL94 HB flammability rating.

The chart below lists our UL94 HB-rated materials and the related printing process. For material data sheets, see the corresponding process capability page.

How do different 3D printed materials behave when exposed to a red hot nickel ball?