STEPS TOWARDS RATIONAL MODELING OF CERAMIC INJECTION-MOLDING

An attempt is made to set up the fundamentals for applying mathematica l process modelling on the basis of rational thermomechanics to the fo rming process of oxide ceramic pastes plasticized by thermoplastic bin ders. Using a continuum description throughout we start with the local balance equations known from traditional continuum mechanics and ment ion the special status of the entropy inequality. Looking for a materi al model as simple as possible but as complex as needed. constitutive theory is used to deduce a simple fluid model (the generalized Newtoni an liquid) with the help of constitutive principles, and for the one-d imensional case the Herschel-Bulkley model is suggested In order to ma ke the theory liable to experimental verification idealizations are ma de concerning flow geometry. Boundary conditions are shortly discussed . Apart from delivering a rational framework for the modelling of cera mic injection molding, the methodological approach applied in this pap er should be of value also for other widely used forming processes in ceramic technology, especially cold extrusion, extrusion at elevated t emperature or hot extrusion.