Executive Summary
Many particulate products are manufactured through powder compaction, in which die
filling is a critical process stage as the die filling performance will determine the process
efficiency and product quality. For aerated powders, the interaction between particle and
the surrounding air could play an important role during die filling. Although die filling
has attracted increasing attention over the last two decades, our understanding on die
filling of aerated powders is still limited. In particular, how the system design will affect
the die filling performance, how significant the presence of air will affect die filling
behavior, and whether powders can segregate during die filling are still not well
understood. To address these questions, both experimental and numerical investigation
were carried out on this project, and this report summarise the key findings on these three
aspects. This report contains 5 chapters: the first two chapters examine the effect of
system design (die shape, size and orientation) with experimental work reported in
Chapter 1, and numerical study in Chapter 2. The effect of air presence on die filling
behavior was presented in Chapter 3 and Chapter 4, with chapter 3 focusing on
theoretical modeling and Chapter 4 on measuring air pressure buildup in the die. Chapter
5 reports the size-induced segregation during die filling.
We would like to acknowledge IFPRI for financially supporting this project. We also
would like to thank Michele Marigo and Tim Freeman for constructive discussions
throughout this project.