(54bn) DEM Modelling of Powder Flow in Metal Additive Manufacturing Systems

In powder-bed based metal additive manufacturing applications, the addition of the powder layers is the crucial first step in building up of the part in 3D and has a significant impact on final part quality. A common technique employed is to add successive layers of metal powder by raking a new layer across the existing surface. Understanding this raking process and how the properties of the powder particles (e.g. size, shape, density, interaction properties) and process parameters (e.g. height of powder layer, rake geometry, rake speed) affect the properties of the bed after raking is crucial in optimizing the performance of the system and ensuring the quality of the 3D-printed part. We will present results of a computational model of this raking process using the discrete element method (DEM). This model directly incorporates the powder’s particle size distribution, particle shapes and experimental measurements of the powder flowability. We have applied this model to simulating raking of both Arcam Titanium powder and CSIRO Manipulated Titanium Powder and it is being applied in improving the performance of existing 3D powder-bed systems and exploring new rake designs and powder morphology combinations in order to deliver products with improved performance.