1997 Volume 25 Issue 1 Pages 37-41
his paper describes the study on wall slip in a conduit for molten polymers in order to improve the efficiency of color and/or material change-over. The velocity distributions in a rectangular conduit were experimentally measured by means of a flow visualization technique with particle tracer under the various contact surface conditions such as material characteristics and roughness on the surface. The slip velocity at a conduit wall was determined by optimal fitting of the velocity distribution calculated from CAE analysis to measured one. The following results were obtained from determined slip velocities; (1) fluoride resin lining is preferable to obtain high wall slip velocity than the case of chromium plating, (2) Smaller irregularities of steel wall gives higher wall slip velocity. Taking into account of the experimentally determined condition for wall and resin temperature, the efficiency of color and/or material change-over in the blow molding machine could be improved.
