Extruder screw, extruder, and method for producing an extruder screw

An extruder, comprising a barrel and at least one extruder screw within the barrel which extruder screw includes an extruder shaft having a prismatic mandrel provided with external teeth and defined by a mandrel longitudinal axis, and at least one extruder segment comprising an external screw, the at least one extruder segment configured for placement onto the mandrel, said extruder segment defined by a longitudinal internal-teeth axis in coaxial relationship to the mandrel longitudinal axis and having internal teeth in mesh with the external teeth of the mandrel so that the extruder segment is connected in fixed rotative engagement with the mandrel, said internal teeth having a profile which has a meshing profile and a prismatic main profile with a main cross-section in an inner area between a first end face and a second end face of the extruder segment, said internal teeth have an edge profile adjacent to at least one of the first and second end faces, said edge profile having an edge cross-section which is smaller than the main profile at least in an area of the meshing profile, wherein the internal teeth have a profile correction, which describes a deviation of the edge cross-section from the main cross-section as a function of an edge distance from a nearest one of the first and second end faces, said profile correction extending up to the edge distance from the nearest one of the first and second end faces of at least 2 millimeters, wherein the profile correction has a profile correction height which is smaller than a tooth height of the internal teeth minus a base rounding radius.

A method, comprising:

• producing a prismatic mandrel with external teeth by hammering with a hammer tool;
• producing a pre-extruder segment with prismatic internal teeth;
• producing an eroding tool with the hammer tool;
• producing a profile correction of the internal teeth by sink erosion with the eroding tool, and
• connecting the pre-extruder segment with the prismatic mandrel for rotation with the prismatic mandrel.