Design of components for additive manufacturing from continuous fiber reinforced plastics

The additive manufacturing of metallic and polymer materials has become increasingly important in recent years due to a wide variety of research activities and the availability of commercial printing systems. On the one hand, this process enables spare parts to be manufactured at very short notice, thus offering low inventory levels and rapid (just-in-time) spare parts availability in the interests of efficient logistics. Particularly with regard to the logistical challenges of existing weapon systems, this can open up new opportunities. On the other hand, it also offers much greater design possibilities for the development of new components, since additive manufacturing is usually subject to significantly fewer manufacturing restrictions.

While the additive manufacturing of metals and unreinforced or short- or long-fiber-reinforced plastics is well developed, there is hardly any usable knowledge available so far for continuous-fiber-reinforced plastics. Although there are already some smaller companies working on the development of appropriate printing systems, commercial solutions are not yet available. In addition, some of these solutions are still based on a layer-by-layer process, so that the production of true three-dimensional reinforced structures is not possible. However, in order to take full advantage of fiber-reinforced structures, this aspect is of key importance.

To address these issues, we are developing an approach that designs both the optimal topology and fiber paths for a given structure. The goal is to design and print 3D optimized structural components and ultimately extend the approach to multi-axis robotic systems.

Development of an optimization framework

• Use of level-set methods to optimize the topology and fiber paths of FRC structures
• Incorporating manufacturing constraints associated with 3D printing of composite materials
• Generation of a G-code for easy 3D printing of optimized parts

3D printing and experimental testing

• 3D printing of demonstrator parts
• Experimental characterization of material properties of 3D printed composites
• Coupling of experimental and numerical data for accurate material response
• Comparison of experimental and numerical performance improvements due to optimization

Extension to robotic 3D printers

• Extension of framework and knowledge to multi-axis systems
• Optimization of components with cylindrical surfaces
• 3D printing of the optimized components

This research has the potential to optimize the performance of AM fabricated FRP components and enable new applications of these materials in the manufacturing industry. With this project, we seek to create a smooth process from design to printing of structurally informed FRP components, avoiding the use of slicing software that compromises their functionality. In this way, the proposed techniques will prove suitable to realize functionally oriented designs and increase the potential of AM parts as critical end-use components.

Project duration: September 2022 to August 2025

Funding volume for the Bundeswehr University: approx. 273.000€.

The project is funded by the Wehrwissenschaftliches Institut für Werk- und Betriebsstoffe (WIWeB).