Application of additive manufacturing to manufacture removable mold-cores for the CFRP production of complex geometries

Carbon fiber reinforced plastic (CFRP) manufacturing often is an expensive, time-consuming small-scale production where most of the products and components are characterized by complex geometric properties. Especially for hollow components it is necessary to use removable mold cores, which are typically made of low-melting metal alloys, and used to shape the inner contour of the component. To improve the time-consuming and costly process of mold-making, this paper describes the application of additive manufacturing (i.e. 3D-printing) for the production of mold cores. The outstanding advantage of additive manufacturing is the very flexible production out of a CAD model without further tools. In the provided case study materials for additive manufacturing were selected and tested for their suitability to manufacture mold cores. For this purpose an exemplary mold core was produced with different additive manufacturing methods and used in common carbon fiber production processes. Since curing in the autoclave places the highest demands on the core, this process has been selected to test the mold cores. A special focus was on the analysis of the dimensional stability and accuracy by measuring the deviations of the inner cores after the autoclave cycle. The analysis was performed by using optical metrology utilising stripe light projection. Finally this case study shows that additive manufacturing can lead to an increase in efficiency in the CFRP production but also that further scientific research and technological development are needed to realize the indicated potentials.