Key Takeaways
- Carbon’s European Patent No. 3158400 (dual‑cure 3D printing) was upheld by the European Patent Office (EPO) Board of Appeal on 24 Sept 2026.
- The decision restored the broadest claim and reinstated several dependent claims that had been narrowed in 2025.
- Dual‑cure technology combines a light‑initiated polymerisation with a thermal post‑cure, delivering parts up to 30 % higher flexural modulus and 50 % greater heat resistance compared with conventional single‑cure resins.
- The ruling secures Carbon’s IP portfolio across 38 EPO member states, reinforcing its market position in high‑performance additive manufacturing.
Carbon Defends Dual‑Cure Patent in Europe
Background of the Dispute
Carbon, a California‑based leader in digital light synthesis (DLS), announced on 28 Sept 2026 that the EPO Board of Appeal had confirmed the validity of European Patent No. 3158400. The patent, filed with a priority date of 24 Oct 2014, protects a method that uses multiple hardening mechanisms—initial UV‑induced polymerisation followed by a secondary thermal cure.
The opposition was launched in 2023 by Oxon IP B.V. on behalf of an unnamed rival. The opponent argued that the claims were overly broad and lacked inventive step. After a 2025 decision by the EPO Opposition Division, the main claim survived but several dependent claims were stripped away. Both Carbon and the opponent appealed, leading to the September 2026 Board of Appeal hearing.
Technical Essence of the Dual‑Cure Process
| Feature | Dual‑Cure (Carbon) | Conventional Single‑Cure DLS |
|---|---|---|
| Primary cure | 405 nm UV light, 2–5 s exposure per layer | 405 nm UV light, 2–5 s exposure per layer |
| Secondary cure | Infrared (IR) heating, 120–180 °C for 30–90 s | None (room‑temperature post‑process) |
| Resulting flexural modulus | 3.2–4.5 GPa (≈30 % higher) | 2.4–3.5 GPa |
| Heat deflection temperature (HDT) | 140–160 °C (≈50 % higher) | 90–110 °C |
| Typical build speed | 30 mm h⁻¹ (layer height 75 µm) | 30 mm h⁻¹ (layer height 75 µm) |
| Material families | Carbon™ RPU, Carbon™ V2, proprietary blends | Standard UV‑cured resins |
The dual‑cure cycle enables the printed part to reach a higher degree of conversion (up to 95 % versus ~80 % for single‑cure), which translates into superior mechanical performance and chemical resistance—critical for end‑use applications such as medical devices, automotive brackets, and aerospace tooling.
Legal Outcome and Its Implications
- Broadest claim restored: The Board affirmed the claim covering “a method of manufacturing a three‑dimensional object comprising (i) exposing a photopolymerizable composition to actinic radiation to form a solidified layer and (ii) subsequently heating the solidified layer to further cure the composition.”
- Dependent claims reinstated: Claims detailing specific temperature ranges (120–180 °C), cure times (30–90 s), and material classes (e.g., urethane‑based photopolymers) were revived.
- Geographic scope: The patent now enjoys enforceability in all 38 contracting states of the European Patent Convention, protecting Carbon’s technology from infringement in major markets such as Germany, France, the United Kingdom, and Italy.
Phil DeSimone, Carbon’s co‑founder and CEO, emphasized that the ruling “validates the strength of our foundational IP and gives our customers confidence that the performance edge of dual‑cure parts is protected across Europe.”
Market Impact
The decision removes a major legal uncertainty that had deterred some European OEMs from adopting Carbon’s high‑performance resins. Analyst forecasts from Smithers Rapra (Q3 2026) now project a 12 % CAGR for dual‑cure material sales in Europe through 2030, compared with a 5 % CAGR for standard DLS resins.
Furthermore, the upheld patent may limit entry of competing dual‑cure systems unless rivals can design around the specific temperature‑time envelope defined in the dependent claims.
Bottom Line
Carbon’s dual‑cure patent survives a rigorous European opposition, securing its core technology across the continent. The restored claims protect the combined UV‑plus‑thermal curing workflow that delivers up to 30 % higher stiffness and 50 % better heat resistance than conventional light‑cured parts. This legal victory not only safeguards Carbon’s IP portfolio but also paves the way for accelerated adoption of high‑performance 3D‑printed components in Europe’s most demanding sectors.
