Recently, we partnered with Henkel, a leading provider of advanced material solutions. Back in February 2019, Henkel teamed up with the 3D printing technologists at Origin to develop new 3D printing materials. As part of that collaboration, Henkel have launched a new photopolymer named Loctite 3955, which is highly flame-resistant, meeting aerospace flame testing standards (UL 94 V-0). It also meets smoke and toxicity standards, making it a very safe and robust production-quality material that is suitable for demanding applications in aerospace, heavy industry, transport, and mass production.
Many common 3D printing materials do not meet flame-resistance standards, so there are limited options available when it comes to industrial materials that need to hold up in extreme applications. Loctite 3955 is expected to be a material of choice, especially because it is the first aerospace-rated 3D printing resin that can be printed using SLA (Stereolithography). Here’s everything you need to know about Loctite 3955’s potential.
Underwriters Laboratories (UL) is an organization that conducts tests on high-performance materials to rate them for a variety of applications. They can conduct over 200 different tests to determine material properties and certify materials for specific applications. A standard test for flame-resistance is the vertical burn test.
The vertical burn test (flammability UL 94 V) measures the fire-resistance of plastic materials. This test involves placing a flame underneath a test specimen for 10 seconds and then measuring the time it takes for the flames to extinguish. A dry cotton cloth is placed below the specimen to test if any molten drippings can ignite flammable materials. Flame intensity, material thickness, drip height, and specimen pre-treatment are all standardized to ensure consistency across tests.
In order to receive the best possible rating of V-0, the specimen must self-extinguish after 10 seconds or less. If molten material drips from the specimen during this time, these drips cannot ignite the dry cotton indicator cloth. If a material receives a V-0 rating, it is considerably more flame-resistant than materials with a V-1 or a V-2 rating. A material with a V-0 rating is likely to be deemed appropriate for use around flammable materials.
Benefits of SLA
Flame-resistant plastics for additive manufacturing already exist on the market, but Loctite 3955 is the first photopolymer (light-activated resin) to meet the V-0 rating. This enables flame-resistant parts to be printed using the stereolithography (SLA) process. There is a small selection of V-0 rated materials made for other additive manufacturing methods such as SLS selective laser sintering (SLS) and Fused Deposition Modeling (FDM), but these printing methods have drawbacks when compared to SLA.
SLA uses a laser to cure liquid resin into solid plastic, layer-by-layer until the part is completed. SLA prints have a very high surface quality and they are extremely accurate. Unlike the rough, textured surface of FDM and SLS prints, SLA prints are production-quality and don’t require post-processing. Resins for SLA can provide unique thermal and optical properties that cannot be replicated with any other additive manufacturing method.
Tough, flame-resistant plastics are highly sought after in aerospace, transport, and industrial applications. These industries have rigorous standards for flame-resistance due to safety requirements and the presence of strong heat sources such as high-intensity combustion and thermal management systems.
Now that Loctite 3955 has been announced, 3D printing can break into industries where it would previously have been deemed infeasible. This opens up many possibilities such as enabling the production of complex, flame-resistant parts that would be too difficult, costly, or time-consuming to manufacture using other methods such as CNC machining or injection molding.
3D printing is always evolving and Henkel’s latest material is living proof of that, showing that there’s no limit to the industries the technology can be applied to.