Abstract: An extruder screw mixing section has a plurality of threads formed on a body of the screw with a pitch defining mixing channels for moving material in a direction from a feed end to a discharge end of the screw. The threads and the mixing channels are interrupted by counter channels that divide the mixing channels into segments of similar diminishing depth profile. A portion of the material moves through the counter channels in direction from the discharge end to the feed end to promote better mixing and melting of the material.

Abstract: An apparatus and a method for determining wear of a feedscrew and barrel combination includes measuring wear of the barrel using a gage plug in a measuring aperture in the barrel or an ultrasonic thickness gauge and measuring feedscrew wear with an eddy current sensor or a dial indicator mounted in the measuring aperture. A system gathers wear data from various production installations, analyzes the data to predict remaining life of the barrel and the feedscrew and generates an order for replacement parts to be manufactured and shipped just prior to the end of the remaining life.