Abstract: A pelletizing die for a pelletizer comprises a base body with holes for melt to pass through; the holes are disposed in rows. Allocated to the holes are wearing-protection inserts, having holes which are in alignment with the holes in the base body. The inserts which are disposed to adjoin each other in a row have a chordal surface where they are turned toward an adjoining insert and are provided with at least one surface of an arcuate segment of a cylinder laterally of the chordal surface.

Abstract: In a method of operating a screw extruder having a drive motor in which the speed of rotation of the drive motor is controlled, in order to achieve as constant a quality of product as possible, the speed of rotation is controlled depending on the specific energy input in such a manner that the specific energy input is maintained substantially constant. A control depending on the product temperature may advantageously be superimposed on the control keeping the specific energy constant in the form of a cascade control. A screw extruder for carrying out the method has a housing in which a screw is mounted, a drive motor having a variable speed for continuously driving the screw, feed devices for supplying basic products, additives and the like, and a control device for controlling the speed of rotation of the screw.