Die Filling of Aerated Powders

Publication Reference: 
Author Last Name: 
Chuan-YU (Charley) Wu, Anastasiya Zakhvatayeva
Report Type: 
Research Area: 
Powder Flow
Publication Year: 
Publication Month: 
United Kingdom

Executive Summary
This report summarizes the work performed during the last 12 month primarily by the project student,
Ms. Zakhvatayeva. It primarily covers a comprehensive study of rotary die filling.
A model rotary die filling system was developed to mimic the die filling process in a typical rotary
tablet press. The system consists of a round die table of 500 mm diameter, equipped with a
rectangular die. The die table can rotate at an equivalent translational velocity of up to 1.5 m/s. The
filling occurs when the die passes through a stationary shoe positioned above the die table. Using
this system, die filling behaviours of 7 commonly used pharmaceutical excipients with various
material characteristics (e.g. particle size distribution, sphericity and morphology) and flow
properties were examined. The efficiency of die filling is evaluated using the concept of critical
filling velocity. It was found that the critical filling velocity is strongly dependent on such properties
as cohesion, flowability, average particle size and air sensitivity index. In particular, the critical
filling velocity increases proportionally as the mean particle size, flow function, air permeability and
air sensitivity index increase, while it decreases with the increase of specific energy and cohesion.
In addition, significant progress was also made in exploring suction filling, an experimental rig was
constructed and a systematical experimental work was perfomed. Some interesting results were
obtained but further data analysis is required. These results will be reported at IFPRI 2019 AGM.
Furthermore, a forced filling system is currently under construction in collaboration with Fette
Compacting GmbH. It is expected that the system will be ready for some preliminary test in Q2 of