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S. Baumgartner, J. Stampfl:
"Digital Materials: Selective modification of material properties";
Talk: Euromat 2019, Stockholm; 2019-09-01 - 2019-09-05.

Additive manufacturing (AM) offers a variety of different technologies with multiple advantages over conventional manufacturing methods. The complexity and customizability of the printed products, makes AM interesting for various applications. Drawback of most commercially available systems, however, are the insufficient mechanical properties and the limited resolution of the additively manufactured parts. With industry calling for tougher and stronger materials, especially for engineering applications, we developed a hybrid 3D-printing technology, allowing us to exploit the advantages of two common AMTs and simulate the toughening mechanisms of natural structures like marine material by locally varying the young´s modulus. A self-developed stereolithography (SL) process provides the basis of the printer and cures the matrix resin layer-by-layer. In between those layers, a pattern of ink droplets can be selectively placed by an inkjet printhead, allowing us to process highly viscous photocureable resins with high resolution and excellent surface quality and mimic the properties of natural structures by jetting thin layers of soft material into a hard matrix. Those so-formed "digital materials" show promising results regarding enhancement of the thermo-mechanical properties, as first experiments indicate an increase of the strain at break and impact strength by over 50% and 40%, respectively - compared to the plain matrix material. Although the global stiffness sligthly decreases, the creep behavior was not influenced negatively. The usage of the inkjet system allows further modifications of the printed parts in a way which has not been feasible up to now: conducting tracks inside complex shaped parts, surface modification with inorganic materials, customized coloring and other multimaterial approaches can be established.

Stereolithography, Inkjet, Digital Materials