Simultaneous extrusion process of projector carbons

The importance of viscosity in the control of wet mixing of both shell and core mix used in projector carbon is discussed. It has been shown that the parallel plate viscometer can be used to control the wet mixing by subjecting random samples of the mix to plastic viscosity and yield stress test. This test is more important for core mix than for shell mix. It is always desirable to use binder content less than the optimum for coremixes. One can use slightly more than optimum for the shell mix to obtain a proper case of extrusion. Under these conditions simultaneous extrusion of both core and shell mixes is feasible.