Additive manufacturing of soft tools – Application of carbon fiber filled PEEK to polymer extrusion dies production

The ongoing improvements within material development of polymer‐based additive manufacturing is resulting in an ever growing availability of highly specialized materials supporting the expansion of the area of application towards more complex and demanding part uses. One example of such an application is the use of additively manufactured tools for polymer profile extrusion. The work presented here aims to exploit the possibilities of integrating additively manufactured carbon fiber filled PEEK tools in the tooling process chain for polymer profile extrusion. Five samples for each of three different extrusion die geometries were manufactured using a fused filament fabrication process with carbon fiber reinforced PEEK material. The dimensional evaluation of a total of 15 dies was performed to ensure the final dimensions of extrudates will be according to specifications. It was found that the process could achieve a reproducibility within 0.2% and 10% standard deviation relative to nominal dimensions depending on the features size. In terms of accuracy, absolute deviations between 10 µm and 500 µm were found depending on the considered dimensions, indicating that a correction factor should be implemented in order for the dies to comply with the geometrical tolerance specifications required to manufacture the extrudate product. The external surface roughness of the dies were evaluated showing an average Sa value of 15.6 μm with a standard deviation of ±3.2 μm across all samples. The relatively high surface roughness could potentially pose an issue when aiming for the production of extrudate products with smooth surfaces (e.g. Ra = 1‐2 µm or below). Further post‐processing of the internal die surface should be explored. Future work will include in‐situ testing of the extrusion dies with life‐time evaluation as well as dimensional and surface evaluation of the manufactured extrudate product.