Modified Modeling of Clay Paste Extrusion through a Circular Die: Beyond the Steady-State

The aim of this study is to develop a mathematical modeling of direct paste extrusion through a circular die going beyond the steady-state, where the coring point becomes evident. The proposed study considers a previous mathematical modeling of clay paste extrusion which did not consider the behavior beyond the steady-state. Therefore, it is proposed that the coefficient of friction is no longer constant after the steady-state. Moreover, beyond the coring point, two types of behavior can be noticed, an acceleration of the extrusion pressure decrease rate or an increase of the extrusion pressure. The latter behavior harms the ceramic industry since it can lead to die damage, lubrication problems, product defects and raise the production cost.