Finite element modelling of cold isostatic pressing

Cold isostatic compaction, where a shaped rubber bag is filled with powder, sealed and then subjected to high all-round pressure to produce a compacted green component, is a common processing route for ceramic components. The key to isostatic pressing is the design of the rubber bag which is in general both different in size and shape from the green body. This paper presents: the results of experiments to measure the powder and elastomer properties; finite element simulations of cold isostatic pressing; and comparisions between the two. The finite element simulations use an elasto-plastic, volume hardening plasticity model for the compacting powder and a finite deformation hyperelastic model for the rubber. The simulations give excellent agreement with experimental results for the pressed component shape, and highlight the importance of including the elastomeric bag within the simulations.