Analysis of feed shoe powder deposition method using a real-time cumulative mass deposition tester

A real-time cumulative mass deposition tester (MDT) was fabricated and tested to study the deposition profiles of powders in complex-shaped dies. The deposition behavior of two different powders (manganese zinc ferrite – MZF¹ and microcrystalline cellulose – MCC²) was studied in an "E" shaped die. The feed shoe deposition method was used to deposit the powders in the die via two different fill directions. The MDT was used to develop real-time fill trends, deposition profiles, contour plots and databases of spatial powder mass distribution in the die. From the results, it was ascertained that both fill direction and die shape affect a powder's deposition behavior. It was observed that the average MCC powder masses deposited in both fill directions were roughly one-seventh the average MZF powder mass. Also, the average voids volume fraction of MCC was roughly double the average voids volume fraction of MZF. Due to its favorable particle characteristics (spherical-shaped particles and low cohesion), the MZF powder filled better compared to MCC. In the case of MZF, the coefficient of variation (COV) values for powder mass were mostly in the range of 5-20%, compared to 25-50% for MCC. Therefore, MCC is expected to be a more difficult powder to process due to its poor flowability and large variations in powder masses during deposition. Overall, the experimental results clearly show that the MDT is an effective and reliable tool that can be used for the real-time measurement of powder deposition profiles in a die.