An extruder screw includes an extruder shaft and at least one extruder segment. The extruder shaft has a prismatic mandrel having external teeth and a longitudinal mandrel axis. The extruder segment has internal teeth and a longitudinal internal-teeth axis and can be slid onto the mandrel, such that the extruder segment can be connected to the mandrel for rotation therewith. The internal teeth have a profile having a meshing profile and, in an inner area between the first and second end faces of the extruder segment, include a prismatic main profile that has a main cross-section. Furthermore, the internal teeth of the extruder segment have an edge profile adjacent to at least one end face of the extruder segment, which edge profile has a smaller edge cross-section than the main profile at least in the area of the meshing profile.

A screw element (100) for an extrusion machine is provided. The screw element (100) includes a first section (200) and a second section. The first section (200 has a first core (212) with a plurality of facets (214) connected to each other along splines (216). The facets (214) and splines (216) extend longitudinally along the screw element (100). The facets (214) and splines (216) can be helically-shaped. The first core (212) increases in diameter in a continuous manner along the direction of flow of material. The first and second sections (200, 300) include one or more helically-shaped flights (218,219) wrapped around the longitudinal axis of the screw element (100).

The invention relates to a process for extruding plastic compositions. The process in particular relates to the conveying, kneading and/or mixing of plastic compositions, in particular of polymer melts and mixtures of polymer melts, above all thermoplastics and elastomers, particularly preferably polycarbonate and polycarbonate blends, also with the incorporation of other substances such as for example solids, liquids, gases or other polymers or other polymer blends.

A mixing section for an extrusion screw has an inlet end and an outlet end as well as alternating wiping lands and barrier lands. The wiping lands have a greater helix angle than the barrier lands. The wiping lands and the barrier lands define inlet channels which narrow toward the outlet end and outlet channels which widen toward the outlet end. A helical pattern of mixing channels is cut into the wiping lands and the barrier lands. The mixing channels may be oriented generally at approximately right angles to the wiping lands and the barrier lands. A portion of the extrudate encounters the inside wall surfaces of the mixing channels and changes direction which improves the mixing of the extrudate.

Extrusion apparatus and methods for use in the design and operation of extrusion screws having multiple channels. In response to rotation of an extrusion screw in an extrusion process, the multiple channels of the extrusion screw can control the temperature, pressure, and/or shear rate of feedstock material flowing through the respective channels. The multiple channels of the extrusion screw can be configured to control the temperature, the pressure, and/or the shear rate of the processed feedstock material by being modeled as one or more model objects having one or more predetermined geometries. The models of the respective channels can then be analyzed using computerized analytical and/or numerical techniques in order to obtain at least estimates of desired temperatures, pressures, and/or shear rates of the processed feedstock material, based at least on specified channel lengths, channel widths, and/or channel depths of the respective channel models.

A fixation device includes: an endless belt member; a first roller arranged inside the belt member; a second roller arranged outside the belt member and biased toward the first roller via the belt member; and a pressure member is biased toward the second roller via the belt member. A facing surface of the pressure member that faces the second roller includes a first flat section and a second flat section that intersect at an intersecting portion. A first end portion of the first flat section on the opposite side to the intersecting portion, a second end portion of the second flat section on the opposite side to the intersecting portion, and the intersecting portion are on an imaginary arc in a cross-section. A radius R of the imaginary arc satisfies, with respect a radius Rp of the second roller, an inequality of (1/2)RpR(19/20)Rp.

The present invention relates to new screw elements for multi-screw extruders with pairs of co-rotating and fully wiping screws.

A single-screw extrusion desulfurization and post-processing system and a method for preparing reclaimed rubber. The single-screw extrusion desulfurization and post-processing system comprises: a single-screw desulfurization device, a single-screw post-processing device and a closed connection device for connecting the single-screw desulfurization device and the single-screw post-processing device, the single-screw post-processing device includes a post-processing feeding unit and a post-processing unit which are connected with each other, and a post-processing screw running through the post-processing feeding unit and the post-processing unit.

An mixing section for an extrusion screw has an inlet end and an outlet end as well as alternating wiping lands and barrier lands. The wiping lands have a greater helix angle than the barrier lands. The wiping lands and the barrier lands define inlet channels which narrow toward the outlet end and outlet channels which widen toward the outlet end. A helical pattern of mixing channels is cut into the wiping lands and the barrier lands. The mixing channels may be oriented generally at approximately right angles to the wiping lands and the barrier lands. A portion of the extrudate encounters the inside wall surfaces of the mixing channels and changes direction which improves the mixing of the extrudate.

The invention relates to a process for extruding plastic compositions, in particular polymer melts and mixtures of polymer melts, above all thermoplastics and elastomers, particularly preferably polycarbonate and polycarbonate blends, also with the incorporation of other substances such as for example solids, liquids, gases or other polymers or other polymer blends with improved optical characteristics, with the assistance of a multi-screw extruder with specific screw geometries.