oa Recent Patents in Additive Manufacturing of Continuous Fiber Reinforced Composites

Background: Additive Manufacturing (AM) enables the accurate fabrication of designed parts in a short time without the need for specific molds and tools. Although polymers are the most widely used raw materials for AM, the products printed by them are inherently weak, unable to sustain large tension or bending stresses. A need for the manufacturing of fiber reinforced composites, especially continuous fiber as reinforcement, has attracted great attention in recent years. Objective: Identifying the progress of the AM of continuous carbon fiber reinforced composites over time and therefore establishing a foundation on which current research can be based. Methods: Elaborating the most related patents regarding the AM techniques for fabricating continuous fiber reinforced composites in the top three institutions, including Markforged company, Xi’an Jiaotong University and President and Fellows of Harvard College. Results: The recent patents in AM of continuous fiber reinforced composites are classified into two aspects: patents related to novel technique methods and patents related to novel structures. The current issues and future development of AM-based composites are given. Conclusion: New structures and techniques have been introduced into conventional 3D printers to enable the printing of continuous fiber reinforced composites. However, until now, Markforged is the only company commercializing the fabrication of this kind of composites based on AM technique. Numerous challenges and issues need to be solved so that AM of continuous fiber reinforced composites can be a new manufacturing method.