INNENISOLIERTE EXTRUDERDUESE.

摘要

A die assembly for plastic pelletizing apparatus of the type including a cooling bath into which the plastic is extruded. The die assembly includes a heated main body (10) having first and second oppositely disposed exterior faces (18; 20) connected by a plurality of relatively small extrusion passageways (22). A layer of thermal insulation material (40) overlies the second face (20), and a cover member (44) having an outer surface adapted to be exposed to the cooling bath is positioned over the thermal insulation material and joined to the main body. Wear resistant insert members (52) formed from a material having a higher coefficient of thermal conductivity than the material from which the cover member (44) is made extend from the outer surface of the cover member through the layer of insulation into the main body. Extrusion outlet orifices are formed through the insert members (52) and define continuations of the extrusion passageways (22) of the main body (10). The relationship between the inserts (52), the cover (44), the insulation (40), and the main body (10) produces an increased heat flow from the main body to the outer die face in confined areas about the orifices. This heat flow advantageously reduces the possibility of freeze-off and plugging of the orifices due to premature solidification of the extruded plastic.