Numerical Simulation of Ram Extrusion Process for Ceramic Materials

The freeze–form extrusion process for aqueous-based ceramic paste is complex due to the non-Newtonian behavior of the paste. In this paper the process is studied numerically using a developed mathematical model. The ceramic paste viscosity is characterized by the Herschel-Bulkley model. The relationship between plunger velocity and extrusion force is computed numerically. The influence of air, which is mixed with the paste during the loading process, is also examined. Due to the compressibility introduced by the trapped air, the plunger force dynamic response is typically dominated by a first order response. It is also shown that the extrusion plunger force depends on the volume of air in the extruder. Good agreement is obtained between the simulation results and experimental data