Abstract: The present invention includes a screw tip for an extruder screw for effecting mixing in an extruder. The screw tip has a shaft portion and at least one mixing element ring connected to the shaft portion, or a mixing element having an aperture therethrough, or both. The mixing element may have two legs connected by a top portion with the aperture between the two legs to allow flow of extrudate therethrough.

Abstract: The present invention includes a screw tip for an extruder screw for effecting mixing in an extruder. The screw tip has a substantially conical outside surface and at least one discontinuous fin. The at least one fin protrudes from the outside surface of the screw tip.

Abstract: Wear resistant extruder screws and methods for their manufacture are provided. The extruder screws include a base alloy screw body having a plurality of flights, a major outer diameter and a minor inner diameter. Each of the flights includes a pair of flight sides disposed between the major outer diameter and the minor inner diameter. The flight sides and minor inner diameter define a root area proximate to their juncture. The preferred extruder screws of this invention include a bond coating layer having a thickness of about 1-10 mils disposed over a major portion of the extruder screw which includes the root area, and a wear resistant coating layer having a thickness of about 10-100 mils disposed over said bond coating layer. The wear resistant coating layer preferably has an ASTM G65 dry abrasion wear rating of less than 10 mm3/kilometer, or, in further embodiments, the bond coating layer has a coefficient of thermal expansion which is in between that of the wear resistant coating layer and the base alloy.

Abstract: Wear resistant extruder screws and methods for their manufacture are provided. The extruder screws include a base alloy screw body having a plurality of flights, a major outer diameter and a minor inner diameter. Each of the flights includes a pair of flight sides disposed between the major outer diameter and the minor inner diameter. The flight sides and minor inner diameter define a root area proximate to their juncture. The preferred extruder screws of this invention include a bond coating layer having a thickness of about 1-10 mils disposed over a major portion of the extruder screw which includes the root area, and a wear resistant coating layer having a thickness of about 10-100 mils disposed over said bond coating layer. The wear resistant coating layer preferably has an ASTM G65 dry abrasion wear rating of less than 10 mm3/kilometer, or, in further embodiments, the bond coating layer has a coefficient of thermal expansion which is in between that of the wear resistant coating layer and the base alloy.