This report summarizes the work performed during the last 12 month primarily by the project student, Mr. El Hebieshy. It primarily covers a comprehensive study of size and density induced segregation.
Segregation mechanisms of powder mixtures during die filling were experimentally investigated. Binary mixtures of powders with either similar particle density but different mean particle sizes or similar particle size but different particle densities were considered to investigate segregation due to size or density differences. A segmented shoe and die were constructed to quantitatively explore, the size induced segregation and density induced segregation during die filling. The results indicated that, during die filling, depending on the shoe speed, different segregation mechanisms came into effect; the sieving segregation mechanism often occurring in hoppers was observed during all condition, where air could freely escape. The fluidization segregation mechanism was observed when the air inside the die, while being displaced by the powder, was only able to escape by permeating through the powder bulk in the shoe. It was also found that the composition ratio of the mixtures only had a minor effect on the segregation tendency for the materials considered in this study.
In addition, progress was also made in exploring rotary die filling, for which a rotatory die filling system was constructed and an extensive experimental work was conducted to compare die filling behaviours using the linear and rotatory die filling systems. A large quantity of data was collected and is currently being analysed and will be reported at IFPRI 2018 AGM. Furthermore, a suction filling system was designed and is currently under construction, it is expected that the system will be ready for research work in early 2018 and preliminary work will be reported at IFPRI 2018 AGM.