Teilprojekt B01
Subproject B01 focuses on the investigation of graded injection-molded components at an early stage of product development, as well as on the development of a highly adaptive production process for injection-molding-analog components with continuously configurable fiber architectures. Due to the nature of the injection molding process, components typically exhibit a constant fiber volume content across the entire molded part. Furthermore, a characteristic fiber architecture is formed, which includes the fiber orientation, length, and distribution. As a result, the production of graded components via injection molding has so far only been possible with considerable effort. In contrast, additive manufacturing enables local variation of the fiber architecture during the layer-by-layer build-up. Two processing routes for the production of graded components have been identified and are being explored. Intrinsically graded components are realized through additive manufacturing, as the layer-wise construction allows for targeted local modification of the fiber architecture. Extrinsically graded components are achieved through customized 3D continuous fiber reinforcement structures that are applied to the printed components. Ultimately, transfer models will be developed to enable the translation of properties from additively manufactured specimens to injection-molded components.
The intrinsically graded test specimens are manufactured in an additive manufacturing cell developed at IKV, in which reinforced and unreinforced materials based on almost any polymer can be processed by means of screw extrusion. This requires a path planning strategy that makes it possible to simulate the specific fiber architecture of an injection molding process. This is made possible by non-planar path planning, which divides components not into parallel planes but into curved layers so that the strand follows a 3D path. This allows fiber orientations to be specifically set. The components additively manufactured in this way are heated above the melting point of the polymer in an external mold in the next processing step and cooled again under injection molding-relevant pressures and cooling rates. This results in graded additively manufactured components that replicate the structure and degree of crystallinity of injection-molded components.
© IKVIn a second process route, extrinsically graded components are produced by applying individual 3D continuous fiber reinforcement structures (e.g. graded tapes made of B03) to additively manufactured parts. By combining both process routes, it is possible to create a smooth transition between the different areas within the component in order to minimize the risk of predetermined breaking points. This new production process can also be used for prototyping graded injection molded components.
The derived knowledge about graded structures is to be implemented in transfer models that make it possible to derive the material-process-structure-property relationships of graded injection molded components from tests on additively manufactured test specimens. The fundamentals of this are also being investigated in sub-project C03, among others. These models are to be made available to the intelligent development and production system (iEP), where they serve as a sound basis for the property forecast to be integrated.
Project data and funding
The project is part of the Collaborative Research Center SFB/TRR 402, which is funded by the DFG under the reference 525069572.
Project start: January 2025
Funding:
