INJECTION HEAD FOR AN EXTRUSION PRESS FOR THE PRODUCTION OF HOLLOW PROFILES, IN PARTICULAR THICK-WALLED PIPES WITH LARGE DIAMETERS, MADE OF PLASTIC, PREFERABLY THERMOPLASTIC PLASTIC

摘要

A tube-making die has an outer tube defining a flow axis and having an inner wall centered on the flow axis. A mandrel is supported within the tube by a plurality of radially extending webs and has an outer wall centered on the die axis and turned toward the inner wall. The walls define an annular axially extending flow chamber that is subdivided by the webs into a plurality of passages. At the juncture between the side walls of the webs and the inner and outer walls of the tube and mandrel, respectively, grooves are formed which extend tangentially of the inner and outer walls and/or radially of the side walls of the web.