Process analytics of 3D printed granular materials

Granular materials, namely a large conglomeration of macroscopic particles, play an important role in many industries, such as mining, agriculture, food and pharmaceuticals. Monitoring and controlling of physical and chemical properties of the granular material is crucial in order to assure high-quality products. This is particularly important in the manufacturing of medicines, where key characteristics of the granular material in primary (e.g. crystallisation) as well as in secondary manufacturing (e.g. compaction) impact quality attributes of the final product. Monitoring these key properties of static as well as flowing granular material is typically performed by methods that exploit the interaction of electromagnetic radiation with matter. These techniques range from near-infrared, Raman and terahertz time-domain spectroscopy to focused beam reflectance measurement and imaging methods. The primary signal of these techniques is influenced by particle properties such as the size, shape, density and chemical composition of the particles. However, the contribution of these physical and chemical particle properties could not systematically and robustly be established. This is very challenging to study experimentally as the granular material typically consists of particles varying in size and shape. Yet, it is of great importance to understand the influence of the different properties on the measurement signal in order to determine the property of interest accurately.

This research project aims to gain insights into the contribution of size and shape of particles composing the granular material on the signals of different process analysers. The overall project goal will be achieved by preparing identical particles with a specific size and shape using additive manufacturing, hot-melt extrusion and injection moulding. 3D printing will be employed to manufacture engineered and well-designed granular material consisting of a large number of identical particles.