In the additive manufacturing of plastics, UV-curing procedures play an important role. However, these types of materials have certain limitations, such as, for example, shrinkage, distortion and/or inadequate dimensional stability under heat. Functional components based on commercial materials can therefore only be produced to a limited extent.
In our research project, we are developing innovative, radically curing, biogenic polymers for photopolymer-based resins without functional limitations. These can then be applied in the three UV-curing additive manufacturing procedures stereolithography (SLA), digital light processing (DLP), and multi-jet modeling (MJM). As the UV-curing component, itaconic acid is used, which is produced biotechnologically from by-products of sugar production. The polymer resins on the basis of this biogenic component thereby replace the materials based on acrylic acid or methacrylic acid currently in use. They can be used to realize UV-curing plastics which, due to the regular distribution of the UV-curing groups in the polymer backbone, exhibit improved properties compared to the conventional materials used in additive manufacturing. In this way, components can be produced which, for example, are characterized by a considerably higher dimensional stability under heat (above 130 °C) and lower embrittlement.
During the project, we apply the developed procedures and the corresponding system technology in order to create initial material samples. With the aid of these samples, we evaluate the potential of materials for various applications, initially for the automotive industry. The fields of application hereby envisaged in the case of success are the serial production of individual interior and exterior components, the manufacture of parts which are no longer available, and special series with a high degree of individualization. Through a successful implementation of the project, the Fraunhofer WKI is supporting an increase in the diversity of materials in the field of the additive manufacture of plastics. Furthermore, with this project, we are making a contribution towards sustainability, as material systems for additive manufacturing will be able to increasingly utilize renewable raw materials in the future.
Our research project is funded by the German Federal Ministry of Education and Research and is mentioned in the brochure "Deutschland druckt dreidimensional" (Germany is printing three-dimensionally, currently only avalible in German).
Fraunhofer Institute for Wood Research 
