Extruder for extrusion manufacturing

摘要

An extruder for extrusion manufacturing one of a hard metal and a ceramic rod with at least one helical inner bore and having a smooth outer surface substantially free of elevations and depressions includes a housing and a die connected to the housing. The mechanism for forcing a plasticized mass through the die is provided wherein the mass is shaped in the form of a billet having a cross-section. A spinner is located in the housing upstream of the die for twisting the mass uniformly over the cross-section of the billet, the spinner being surrounded by an axial flow of the mass. A smooth channel is located downstream of the spinner such that the mass emerges from the channel through the die and a mechanism is provided suspending a filament in the mass wherein the filament follows a twisting movement of the twisted mass so as to form a helical inner bore therein. The housing includes an interior coaxial mandrel supporting the spinner, the mandrel being located upstream of the spinner wherein the filament projects from a downstream end of the spinner into the die at eccentrically arranged locations.