In a recent study, scientists have developed an algorithm for planning the head path of an FDM 3D printer that uses continuous fiber composites. The objective is to provide a path that avoids intersection points in the same layer, since this causes breaks in the fiber bundle contained in the matrix. With this new algorithm, a user could better control composite prints and get even stronger and more durable parts. The team behind this project relied on an Eulerian graph and the Hierholzer algorithm to generate this print path by integrating different adaptive constraints.
Composite materials are popular with additive manufacturing users today because they offer a superior strength-to-weight ratio, often even compared to metals, without sacrificing geometric complexity. The market has grown rapidly with more manufacturers offering continuous fiber 3D printing solutions. As a reminder, continuous fibers are deposited at the same time as the matrix, hence the need for a dedicated 3D printer. The short fibers are mixed with the base polymer, which is then extruded by the machine. As you can imagine, each process will have different results but also its own limitations. In continuous fiber 3D printing, the deposition of the fibers creates greater complexity in terms of both the nozzle path and the cut. If too much material is deposited in the same layer, especially at intersection points, the fiber bundle can break. Therefore, the areas where the fibers can cross must be limited.
And this is the point on which the scientists focused their research. The idea is to generate a path of a single stroke, therefore continuous, that does not cut the filament of each layer and therefore creates these intersection points. This printing model gave rise to an Eulerian graph, or a path in a graph that visits each edge exactly once. Based on Hierholzer’s algorithm, the team was able to determine an optimal print path for the FDM 3D printer head. Each step in the algorithm corresponds to a single trace path. They then printed 3 structures and viewed the results with an X-ray scanner, the ScanXmate-L080TT.
At the moment some small deficiencies have been noticed in the curved part of the vertices. Therefore, the team is in the process of fine-tuning the algorithm’s parameters to minimize these flaws, particularly in terms of fiber alignment or reproducibility of a shape. However, the researchers explain that this calculated trajectory has been designed for complex geometries, with lattice structures. One can imagine how it could be combined with design principles like topological optimization. If you want to learn more about this project, read the study published HERE.
What do you think of this new method to optimize a path for carbon fiber reinforced thermoplastics? Let us know in a comment below or on our Linkedin, Facebook and Twitter pages! Don’t forget to sign up for our free weekly newsletter here, bringing the latest 3D printing news straight to your inbox! You can also find all our videos on our YouTube channel.
*Cover photo credits: Markforged