Project Details
Projekt
Research into the interactions in the additive manufacturing of elastomer components with functionally graded material properties using a novel dosing and mixing unit and an inline-capable vulcanization unit - ElastAM
Subject Area
Plastics Engineering
Primary Shaping and Reshaping Technology, Additive Manufacturing
Primary Shaping and Reshaping Technology, Additive Manufacturing
Term
since 2025
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 563931574
The additive manufacturing (AM) of highly filled and crosslinked rubber compounds has developed strongly in recent years, partly due to the applicant's scientific work. Systems have been set up and put into operation that can additively process high- and low-viscosity rubber compounds into full-volume or structurally graded components (by varying the "infill") using the layer-based FDM (Fused Deposition Modeling) process. Due to the rheological flow behavior of non-crosslinked elastomer materials, these layered components can collapse due to their own weight above a critical layer height specific to the recipe. This currently significantly restricts the geometric freedom of the AF process, especially for tall components. After the AF process, the geometry of the components is stabilized by the crosslinking process in a post-process step in a high-pressure autoclave. A time-defined chemical reaction is started here, the kinetics of which depend on the pressure and temperature and the composition of the crosslinking system. This process transforms the plastically deformable printed rubber into an elastic and geometrically stable part. This additional external process step currently extends the production time. Initial preliminary investigations on an external test stand with an IR emitter have shown potential for using the energy input of the beam source to heat and crosslink individual printed layers in order to stabilize them geometrically and achieve corresponding component heights. While the adjustment of component properties on a macroscopic and mesoscopic level by changing the basic shape, e.g. by adapting the external properties of components using lattice structures, has already been successfully implemented, adaptation on a microscopic level is still largely unexplored. Through microscopic adaptation, macroscopic component properties such as density, hardness or mechanical properties can be adjusted locally and components can be functionally graded. In this project, a material system consisting of a low-viscosity rubber base mixture (rubber, fillers, additives) and a flowable crosslinker material mixture (carrier material, crosslinking system) is to be developed and researched, which realizes the AF of graded mono-material components. In order to make this possible, an AF process for mixing the components in variable material mixing ratios with a dynamic mixing unit is being developed, which eliminates the latency times previously caused by static mixers. Based on the preliminary investigations, an IR vulcanization unit will also be integrated into the printer in order to investigate the "inline" capability of the crosslinking process of the additively manufactured elastomer components.
DFG Programme
Research Grants
