In Line Compounding/Injection Molding with a Discontinuously Operating Twin Screw Extruder

摘要

For standard injection molding a granule length of 10 - 12 mm is used in long glass fibers applications to achieve an optimum fiber length distribution in the part. The resulting fiber length in the part is limited to approximately 3-5 mm. To increase the fiber length in the molded part it is necessary to directly compound the glassfibers into the polymer on the injection molding machine. The presentation describes a very cost effective way to produce injection molded parts with long glass fibers on a system where a discontinuous running twin screw extruder fed with glass rovings is directly mounted on a two stage injection unit. The advantages of this configuration compared to a continuously running twin screw extruder and discontinuously running single screw extruder mounted on a two stage injection unit were evaluated and are described in depth.