Screw drive power of single screw plasticating units with smooth barrels

In this contribution the computation of the drive power of single screw mac hines with smooth feed sections for extruders and injection molding machine s will be presented. The drive power will be determined by means of the she ar stresses at the barrel wall for the completely melt-filled channels as w ell as for the polymer melting section of the screw. In order to determine the shear stress and thus the power consumption the correct velocity profil es in the screw channels must be known, taking into account the non-Newtoni an flow behavior of the polymer melt. For analytical solutions of this prob lem extreme simplifications are necessary. For this reason approximation eq uations are set up, which are based on numerical tests and by means of whic h a reliable determination of the screw drive power is possible, knowing th e throughput the temperature development across the screw as well as the me lting profile.