in this paper, the direct extrusion process of bimetallic rods in conical dies is analyzed by an improved upper bound method. the deformation zone is subdivided into six smaller zones and by considering a non-spherical entrance boundary to the deformation zone, a velocity field is presented which is different from velocity fields employed in previous studies. the total power consumption of the ...

A novel multi-functional vertical high shear kneader has been developed. Wet kneading of pharmaceutical powders was conducted under various blade components and operating conditions. Compression properties of wet kneaded mass was analyzed and dispersion of hinder liquid (water) among the mass was investigated by assaying tracer aqueous pigment. Pellets were produced through a dome type extrusio...

Capillary rheometry simulates polymer extrusion in a simplified way. It allows the characterisation of polymers by means of determination of the viscosity function and extrudate swell. As regards viscous properties, there is still a lack of constitutive characterisation of rubber blends. In this contribution new concepts are presented how the viscous properties are computed without using common...

The rheological properties of wet powder masses used in the preparation of pharmaceutical pellets by extrusion/spheronization were evaluated utilizing capillary and rotational rheometers. A ram extruder was used as a capillary rheometer to construct flow and viscosity curves for each wet mass under different extrusion rates and die geometry. As a result, shear thinning behavior was observed for...

The present study addresses the issue of the steady regime assumption in flows involving short fibers usually introduced for the analysis of rheometric flows or in the simulation of some kind of forming processes as is the case of the extrusion. For this purpose we analyze the solution of the Fokker-Planck equation in simple shear flows for both two-dimensional and three-dimensional systems. De...