The ZSE-27 MAXX direct-to-sheet system from Leistritz, Somerville, N.J., is said to facilitate rapid in-line compounding and production of prototype sheet samples. Benefits of direct sheet extrusion include the product having one-less heat/shear history, and economic savings inherent with bypassing the pelletization step.
The system is comprised of: A ZSE-27 MAXX co-rotating, intermeshing, twin screw extruder with a 52/1 L/D with modular barrels and segmented screws (1.66/1 OD/ID ratio); 40 kW water-cooled motor; Q2 LSB-26 side stuffers for filler/fiber introduction; Allen-Bradley Compact Logix L3 PLC with PanelView Plus 15-in. touch screen HMI; a gear pump front-end attachment with 20 cc/rev capacity and 5 HP AC motor; a 14-in. sheet/film flex-lip die; and a three-roll stack.
According to Leistritz, the PLC distributive processing control architecture is particularly important when integrating systems from multiple suppliers with distinctly different technologies. The ZSE-27 MAXX twin screw extruder system and downstream lamination system each have their own PLC and HMI interface. These two systems can operate independently or together via an Ethernet communications link to allow fully integrated system sharing of recipe, data acquisition and logic/alarming.
The pressure-control algorithm is also said to be novel. Typically the gear pump rpm is locked to set a constant volumetric rate to the die. The tuning algorithm in the PLC analyzes the inputs from key points in the system, makes numerical calculations, and applies corrections to the extruder screw rpm and feed rate to maintain the gear pump inlet pressure at a given set point.
The line is available for trials at the Leistritz lab.
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