Abstract: The present invention relates to screw elements for multiscrew extruders with pairs of co-rotating and fully wiping screws, to the use of these screw elements in multiscrew extruders and to a method of generating screw elements according to the invention.

Abstract: An extruder for welding plastic components, comprising a front part for plasticizing and ejecting additional plastic welding material, and a rear part, for feeding and breaking up a continuous filament made of the additional plastic material. The rear part comprises a feed channel that cooperates with a worm screw for the advancement of the filament. The feed channel is delimited by the thread of the worm screw on one side and by a sliding surface for the filament on the opposite side. The distance between the sliding surface and the crest of the thread decreases in the direction in which the filament is fed, in order to provide scoring of increasing depth on the filament. The thread comprises at least one discontinuity of the worm that has a sharp discontinuity end for cropping the filament at the scoring.