 High-performance components are necessary for productive, reliable blown film lines. New screw concepts and optimization of existing concepts enable this three-layer blown film line to process various polyethylene types such as LDPE, LLDPE, HDPE, and ionomers, as well as new metallocene and polypropylene raw materials. These raw materials can be processed without screw change, and the service life of the plasticating units has been increased by coating barrel and screw materials with a hot isostatic pressing (HIP) hard metal.The system minimizes film thickness variations by controlling all variables that can be influenced. The coextrusion die has been optimized for flow characteristics. Reduced melt channel length gives shorter purging periods, and improved die heaters minimize or even prevent melt fracture in the production of LLDPE and metallocene composites. Coextrusion dies are equipped with air exchange systems, and the bubble cooling system makes a major contribution to product quality. Dual-chamber air rings and internal-bubble cooling systems for various applications enable optimum bubble stabilization and high output rates. Different systems are tailored for sizing and bubble collapsing requirements. Both the length and the number of segments of the sizing basket are determined by the product and its dimensions. Depending on requirements, the bubble-collapsing unit is equipped with easy-running carbon fiber rollers, brush rollers, combinations of rollers and wooden slats, or driven rollers—all ensuring optimum product quality. A turner bar system is capable of handling sticky film as well as film with sensitive or dull surfaces. A general purpose film winder is used for the multilayer extrusion process and is suitable for all winding modes—even low-contact pressures and tensions. Forward and reverse winding and nonadhesive transfer are available. Laminating and packaging films for different demands can be produced on this line, including film thicknesses of 15 to 250 µm, trimmed film widths of up to 1600 mm, and production speeds up to 130 m/min at a throughput of 350 to 400 kg/hr. Reifenhauser Inc. Ipswich, MA; (978) 412-9700 www.reifenhauser.com |
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