Markforged Inc v. Continuous Composites Inc

1. Case Identification

• Case #: IPR2022-00548
• Patent #: 9,511,543
• Filed: March 3, 2022
• Petitioner(s): Markforged Inc.
• Patent Owner(s): Continuous Composites, Inc.
• Challenged Claims: 1-15, 17-41

2. Patent Overview

• Title: Method and Apparatus for Continuous Composite Three-Dimensional Printing
• Brief Description: The ’543 patent relates to a method and apparatus for additive manufacturing. The technology involves simultaneously extruding a composite of at least two materials, where a liquid primary material (e.g., a resin) completely encases a solid continuous secondary material (e.g., a fiber strand), and then curing the liquid material to form a hardened object.

3. Grounds for Unpatentability

Ground 1: Obviousness over Wohrl - Claims 1-3, 6-8, 15, and 38-40 are obvious over Wohrl.

• Prior Art Relied Upon: Wohrl (U.K. Patent Application GB2213793).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Wohrl, which describes a method for manufacturing a fiber-reinforced component by wrapping a core with a resin-impregnated fiber, disclosed all limitations of the challenged claims. Wohrl’s resin matrix was identified as the claimed "primary liquid material," and its fiber strand was identified as the "secondary material." The process of laying this composite material from a fiber-laying device was argued to meet the "extruding" limitation. Petitioner contended that Wohrl’s disclosure of precuring the resin to make it "gel" and "stick" taught the claimed step of "hardening at least a portion of the primary material," which in turn created an "anchor point." The relative movement between the laying device and the part was argued to disclose "pulling" the path from the extruder, as claimed.
  • Motivation to Combine (for §103 grounds): Not applicable (single-reference ground).
  • Expectation of Success (for §103 grounds): Not applicable (single-reference ground).

Ground 2: Obviousness over Wohrl and Ma - Claims 4, 5, 9, 11, 12, 14, 17-22, 24, 25, 27-29, and 41 are obvious over Wohrl in view of Ma.

• Prior Art Relied Upon: Wohrl (U.K. Patent Application GB2213793) and Ma (a 2001 Dissertation Thesis on Solid Freeform Fabrication).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Wohrl taught the base method, and Ma provided specific teachings that rendered additional claim limitations obvious. Ma explicitly taught cutting the fiber towpreg "where necessary" to create complex parts, meeting the limitation of "cutting the at least one secondary material" (claim 4). Ma also described a "Passive material supplying method" where the towpreg is "pulled out by the object" due to its "pulling force," teaching the limitation of "applying tension to the at least one path" (claim 5). Furthermore, Ma taught using multiple components in the resin to expedite curing (claim 9), using materials like glass fiber (optically conductive) or metal (electrically conductive) for the fiber (claim 12), and the importance of achieving high affinity between fiber and matrix for complete wetting to create "substantially void-free" paths (claim 14).
  • Motivation to Combine (for §103 grounds): A POSITA would combine Wohrl and Ma because both are directed to computer-controlled methods for 3D printing with resin-impregnated fibers. Ma was said to complement Wohrl’s general method by providing specific, predictable, and beneficial details regarding material selection, process control (e.g., cutting), and improving material properties, which would have been a natural and logical enhancement of Wohrl's system.
  • Expectation of Success (for §103 grounds): A POSITA would have a high expectation of success because Ma’s teachings were directly applicable to Wohrl’s system and addressed known considerations in composite manufacturing, yielding predictable improvements without undue experimentation.

Ground 3: Obviousness over Wohrl and Lipsker - Claims 10, 13, 30-33, and 35 are obvious over Wohrl in view of Lipsker.

• Prior Art Relied Upon: Wohrl (U.K. Patent Application GB2213793) and Lipsker (Patent 6,153,034).
• Core Argument for this Ground:
  • Prior Art Mapping: Building on Wohrl's foundational teachings, Petitioner argued Lipsker supplied the missing elements for this set of claims. Lipsker taught forming multi-material prototypes by dispensing "wires of different materials," thus disclosing a secondary material comprising "multiple materials" (claim 10). Lipsker’s method of building objects by stacking individual layers, combined with its disclosure of a cutter to form "discrete or non-continuous portions," was argued to teach "extruding a plurality of paths" (claim 13). The combination of Wohrl and Lipsker was also argued to render independent claim 30 obvious, with Lipsker teaching the extrusion of multiple distinct paths to build an object layer-by-layer.
  • Motivation to Combine (for §103 grounds): A POSITA would combine these references as both disclose automated, computer-based methods of forming 3D objects from fiber-like material and a curable substance. Lipsker represented a known approach in the field and offered clear, beneficial improvements to Wohrl’s continuous fiber process, such as using a cutter to create more complex geometries and using different wire types for multi-material parts.
  • Expectation of Success (for §103 grounds): Success was predictable because applying Lipsker’s well-understood techniques for cutting and layering to Wohrl’s system involved combining known elements to achieve a predictable result without changing the fundamental principles of either system.
• Additional Grounds: Petitioner asserted additional obviousness challenges, including that claims 26, 34, 36, and 37 are obvious over Wohrl, Ma, and Lipsker, and that claim 23 is obvious over Wohrl, Ma, and Crump (Patent 5,121,329), which taught adjustable extruder nozzles.

4. Arguments Regarding Discretionary Denial

• Petitioner argued against discretionary denial under 35 U.S.C. §325(d), stating that the primary reference combinations asserted were never considered by the examiner during prosecution.
• Petitioner also argued against discretionary denial under Fintiv, asserting that the parallel district court litigation was in a very early stage, a motion to stay would be filed, the court had not set a trial date, and there had been no significant investment in the court proceeding. Petitioner contended that the strong merits of the petition weighed heavily in favor of institution.

5. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-15 and 17-41 of the ’543 patent as unpatentable.