Abstract: A system and process is provided for cladding the interior of plasticating barrels or any other interior surface. The cladding operation uses a laser head that carries out a spiral welding operation to create a smoother lining than is capable with conventional welding techniques. A number of different techniques can be used, including the use of feeding laser energy at one end of a tube to be reflected from laser aiming optics inserted through a second end of the tube. Unidirectional welding can be used to facilitate gravity as a smoothing agent. In another embodiment omnidirectional welding can be carried out using a shaped mirror and a donut-shaped laser pattern. The cladding operation can be simplified by baking a coating of the welding matrix and anti-abrasive material onto the interior of the surface to be clad prior to the welding operation.

Abstract: An apparatus and method for controlling thermoplastic mixing in a plastic extrusion machines used for injection molding, blow molding or other reciprocating molding process. The plastic extruder having a rotating helical screw within a cylindrical shell with an automatic shut-off and mixing valve secured to the helical screw at the downstream end of the screw. The automatic shut-off and mixing valve includes a unitary valve body with a poppet. A plurality of mixing groove pairs are arranged extending substantially longitudinally on the surface of the valve body. Select angular bores extend from the groove pairs to the poppet. The poppet is axially movable within and rotatable relative the valve body. The poppet has an axial stem extending into a longitudinal axial bore within the valve body. An elastic means is positioned on the rearward end of the poppet maintaining the valve in a normally closed position against a seating surface of the valve body when there is no rotation of the helical screw.

Abstract: A screw for use in an plasticating injection apparatus includes a plurality of interrupted primary flights. An outer surface of a primary valley is formed by the primary flights and features a plurality of plateaus. The plateaus span adjacent sections of the primary flights and define shallow levels between deeper levels of the primary valleys. This depth differential contributes to a turbulent mixing action which, along with the primary and secondary valleys, contributes to improve mixing action within a metering section of the screw. The primary flights are interrupted by secondary valleys which are of opposite hand to the primary valleys.