Simulation of Powder Flow in a Die Shoe

摘要

The flow properties of powder are poorly understood even though Powder Metallurgy (PM) and particle related industries are currently experiencing a massive growth. In this paper, we examine the flow of powder inside a die shoe, which is used for die filling. Numerical experiments have been conducted which allows a deeper understanding of the die-filling process even before the actual die filling takes place. The influence of particle shapes in the flow has been investigated using numerical models based on the discrete element method (DEM) in which particles of three different geometric compositions were considered. It is found that mound formation took place in all the three particle shape compositions. However, there are distinct variations in particle arrangement and voids formation. Simulations show that circular particles are packed closer together but polydispersed disks experienced much more random and turbulent flow. The most voids appeared in particles composed of polydispersed ellipses, followed by polydispersed disks and finally monodispersed disks. Particle shapes certainly have an influence in the quality of a die filling, thus density variation within a die fill. The numerical study provides new insights, which enhance our understanding of the mechanism of die filling even before the process begins.