Continuous Composites Sues Anisoprint Over Continuous-Fiber 3D Printing Patents

Continuous Composites has filed a patent infringement lawsuit against Anisoprint and its Fibre Seek subsidiary, alleging that the FibreSeeker 3 continuous fiber 3D printer violates ten of its US patents. The complaint marks the latest escalation in a long-running dispute over who controls the foundational technology for printing continuous fiber reinforced parts.

Continuous Composites, based in Coeur d'Alene, Idaho, developed its CF3D continuous fiber printing platform and filed its first patent application for the process in 2012. The company says it now holds more than 120 allowed US patents and over 40 international patents covering composite additive manufacturing methods and systems. The lawsuit claims Anisoprint's products use a similar continuous fiber co-extrusion approach that falls within the scope of those inventions.

The complaint specifically names the FibreSeeker 3 as an infringing product. Continuous Composites also says it began licensing discussions with Fibre Seek back in 2023, provided a term sheet in June 2024, and made repeated attempts to negotiate through 2024 and 2025 before going to court.

Steve Starner, CEO of Continuous Composites, said the company did not rush into litigation. He described the lawsuit as a last resort after nearly three years of what he called good-faith discussions failed to produce a resolution. The company previously won a 25 million dollar settlement from Markforged in 2024 after a federal jury found that rival had infringed one of its patents.

What is at stake

Continuous fiber 3D printing sits at the intersection of composites manufacturing and additive manufacturing. It produces parts that are significantly stronger and stiffer than typical thermoplastics, which makes the technology attractive for aerospace, automotive, and tooling applications. The patents at issue cover methods for combining continuous reinforcement fibers with polymer matrix materials during the build process, something that several companies now claim to do in slightly different ways.

If the court finds in favor of Continuous Composites, Anisoprint could face an injunction blocking US sales of the FibreSeeker 3 and potentially other products. It could also be ordered to pay damages, though the exact amount would be determined later in the proceedings. For now, Anisoprint has not issued a public response to the allegations.

The case adds to a growing list of patent fights in the 3D printing industry. As the market for continuous fiber and composite additive manufacturing grows, companies are defending their intellectual property more aggressively. Buyers and investors should watch this case closely, because a broad ruling for Continuous Composites could reshape licensing terms across the entire sector.