Measuring powder flow parameters of inert simulants for 3D printing explosives

Abstract. It is important to study the powder behavior of energetic materials before using them in either conventional or novel manufacturing processes such as 3D printing to ensure the safe handling of the energetic materials. This project studies different powder materials as simulants for RDX powder. The focus is to familiarize with the Freeman Technology FT4 powder rheometer to gather data on the flowability and powder properties of the simulants powders and compare them to the powder properties of RDX powder, in particular with a focus on applications in additive manufacturing. The work focuses on data analysis of FT4 results in order to obtain measurements that provide an accurate and thorough understanding and can be used to evaluate if the selected powder simulants can mimic the powder behavior of RDX. The experiments are done in atmospheric conditions and the powder simulants used are inert with different particle size distributions. The conducted experiments are stability and variable flow rate test, aeration test, compressibility test, permeability test, shear cell test, and wall friction test. The stability and variable flow rate test and the aeration test showed that ammonium sulfate requires more energy to flow. The compressibility test showed that melamine is more compressible in comparison to ammonium sulfate. Moreover, the shear cell test showed that melamine is more cohesive, and the wall friction test showed that ammonium sulfate is less cohesive to walls compared to melamine.