Fundamental understanding of the deposition of powders into dies is essential to optimizing processes such as compaction. Toward this end, models were developed and verified to simulate the filling characteristics for three deposition methods into shallow dies. Understanding of the filling process for shallow dies represents the key first step towards gaining fundamental knowledge of filling deep dies. The three different filling methods modeled were: the feed shoe, rotational rainy, and point feed, which represent the commonly used methods to fill dies and containers. A free flowing, spray dried battery powder mixture (d50=600 μm) was filled into a circular shallow die (35 mm diameter x 6.5 mm deep) at 20 mm/s feed shoe speed equivalent to 26 g/min filling rate. A physics based explanation of the filling process, i.e., pressure vs. time for a specific location at the bottom of the die, is included that provides a rational basis for the use of Chapman-Richards model. In order to evaluate the goodness of the model, the average root mean square error (RMSE) and the mean value of average relative difference (ARD) of the models were calculated. The results showed that 1) the RMSE for feed shoe, rotational rainy, and point feed were 0.16 dm (dmdecimeter, fill head equivalent of measured pressure), 0.44 dm, and 0.32 dm, respectively, whereas, the ARD for feed shoe, rotational rainy, and point feed were 7%, 16%, and 11%, respectively; 2) the deposition profile for feed shoe and rainy fill were sigmoidal in shape, while for the point feed it was linear.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Materials Science(all)