Plasticizing system reduces screw recovery time, enables molders to increase throughput

06-Jan-15

A high-rate plasticizing unit incorporating an innovative screw design produces enhanced-quality melt at rates that make possible shorter cycles in injection molding of high-speed, thin-wall packaging, it was announced by Nordson Corporation. The Nordson Xaloy Quantum™ plasticizing system includes a barrier screw designed to increase the rate of plastication for unmelted material while minimizing shear forces on polymer that is already in a molten state. Along with the innovative screw, Nordson supplies a custom-designed poppet-style non-return valve, whose free-flowing channels prevent polymer degradation and whose rapid shut-off ensures shot-to-shot consistency. “The Quantum system delivers optimum melt quality at a rate that reduces actual screw recovery time by 10 to 15% in comparison with existing high-performance plasticizing units, enabling it to keep pace with the exceedingly short cooling times in high-volume production of thin-wall parts,” said Tony Genova, engineering supervisor for screw manufacture. “As a result, molders who use the Quantum processing system are often able to reduce cycle times, increasing profitability and yielding a rapid return on investment.” A barrier screw has a middle section designed to separate solids from molten polymer so that the heat and shear forces applied to the solids can be maximized, increasing the plastication rate. “In the screw for the Quantum system, we strive for a mass balance throughout the length of the screw, accommodating the differential between the bulk density of the pellets being fed into the system and the density of the molten polymer,” said Mr. Genova. Nordson custom designs each screw for the Nordson Xaloy plasticizing system to meet specific customer requirements.