3D-Printed Material to Replace Ivory

With an elephant-friendly alternative to ivory, developed by TU Wien and Cubicure, old artefacts can be restored with high precision.

For centuries, ivory was often used to make art objects. But to protect elephant populations, the ivory trade was banned internationally in 1989. To restore ivory parts of old art objects, one must therefore resort to substitute materials – such as bones, shells or plastic. However, there has not been a really satisfactory solution so far.

On the right: The new material Digory, ivory on the left

  Credit: TU Wien 

TU Wien (Vienna) and the 3D printing company Cubicure GmbH, created as a spin-off of TU Wien, have now developed a high-tech substitute in cooperation with the Archdiocese of Vienna’s Department for the Care of Art and Monuments and Addison Restoration: the novel material “Digory” consists of synthetic resin and calcium phosphate particles. It is processed in a hot, liquid state and hardened in the 3D printer with UV rays, exactly in the desired shape. It can then be polished and colour-matched to create a deceptively authentic-looking ivory substitute.

Beautiful and Mechanically Stable

“The research project began with a valuable 17th-century state casket in the parish church of Mauerbach,” says Prof. Jürgen Stampfl from the Institute of Materials Science and Technology at TU Wien. “It is decorated with small ivory ornaments, some of which have been lost over time. The question was whether they could be replaced with 3D printing technology.”

The team already had experience with similar materials: the research group also works with ceramic materials for dental technology, for example. Nevertheless, it was a challenging task to develop a suitable substitute for ivory: “We had to fulfil a whole range of requirements at the same time,” says Thaddäa Rath, who worked on the project as part of her dissertation. “The material should not only look like ivory, the strength and stiffness must also be right, and the material should be machinable.”

Stereolithography in the 3D printer

Through numerous experiments, Thaddäa Rath and other members of the team from TU Wien and Cubicure succeeded in finding the right mixture: Tiny calcium phosphate particles with an average diameter of about 7 µm were embedded in a special resin, together with extremely fine silicon oxide powder. The mixture is then processed at high heat in Cubicure’s 3D printers using the hot lithography process: Layer by layer, the material is cured with a UV laser until the complete object is finished.