​DLR project demonstrates hybrid AM process for composites

Latest DLR development in 3D printing combines additive extrusion technologies and AFP to present a new approach for manufacturing complex thermoplastic composite structures. The DLR Institute of Structures and Design (DLR, Stuttgart, Germany) develops design strategies and the associated manufacturing technologies for the production of innovative, high-performance structures in aerospace applications. An important tool for the implementation of modern structural concepts is the additive manufacture (AM) of thermoplastic composites. To fully exploit the potential of these technologies, DLR is developing a hybrid manufacturing process combining additive extrusion technologies (3D printing) and automated fiber placement (AFP).

According to the company, this hybrid process combines the flexibility of 3D printing with the performance of AFP laminates and enables the production of composite components that are not feasible with other composites manufacturing processes. Possible applications include the production of multifunctional primary structures using functional materials, load-optimized sandwich structures with arbitrary curvature or individually stiffened shell structures.

In a current project, the full additive manufacturing of sandwich structures is demonstrated. In four manufacturing steps, the tooling, the two facesheets and the core are built up additively. The joining between the facesheets and the core takes place in-situ during the 3D printing or AFP processes, which ensures a single-variety component without downstream joining steps. To enable use in primary structures, only high-performance thermoplastics are used. In the demonstrator presented, the cover layers are deposited from carbon fiber-reinforced low-melt polyaryletherketone (CF/LM-PAEK) unidirectional (UD) tapes. The overprinting is done with short fiber-reinforced polyetheretherketone (PEEK) in a robotic fused granular fabrication (FGF) process.