Hardmetal is a powerful material, characterized by its high degree of hardness, wear resistance and toughness. The complexity of hardmetal components is currently limited by conventional shaping processes. Only relatively simple geometries can be realized. However, modern tools often require much more complex geometries, such as helical or meandering cooling channels inside the component. These geometries need to be produced in time-consuming and cost-intensive processes by cutting and grinding hardmetal blanks with diamond tools or through eroding methods. Therefore, the researchers of Fraunhofer IKTS are developing complex hardmetal tools by using 3D printing methods. The quality of the products obtained is fully up to par with high-performance tools manufactured with conventional methods.
In the binder-jetting printing method used, the starting powders or granulates are wetted locally and bound with an organic binder through a print head. The heat treatment, which needs to be adapted specifically to the composition, drives out the binder in a first step before compacting the component through high temperature and pressure. By optimizing the process chain, the researchers successfully obtained components which are fully sealed and come with a perfect hardmetal microstructure and excellent mechanic properties. By precisely varying the binder matrix, it is possible to adjust bending strength, toughness and hardness – the lower the binder content within the hardmetal, the harder the component will be. The prototypes manufactured at Fraunhofer IKTS have a binder content of 12 or 17 weight percent and a microstructure that is similar to that obtained through conventional production routes.