5. Sheet extrusion die

Conventional nozzles are equipped with coathanger manifolds, restrictor bars and, if necessary a flexible lip. Adjustments are usually carried out manually. Using automatic systems in sheet extrusion for thickness measuring is rare. Most recently sheet dies with membranes are being used instead of restrictor bars, the basic idea behind this is to reduce flow channel wall thickness as far as possible, in order to make it deformable. The resulting advantages are as follows:

The membrane technology is available for both single as well as multi-channel dies and also for coex adapters.

6. Polishing stack

Apart from some exceptions, three-roll calenders are used. While the vertical calender dominates Styrenics extrusion, this device is no longer in operation for polycarbonates. Here the 45° or horizontal arrangement of the calenders has won through, with the calender often adjustable in its position. Thus cooling conditiones and sheet thickness are matched in an optimal way. The calenders are heated with water or oil.

8. Other devices

Downstream from the polishing stack follow the sheet conveyor, the laminating machine for double coating with protective film or sheets with optical qualities (primarily Makrolon^® sheets), longitudinal and transverse separators, storage and stacking facilities.

The cutting devices are typically operated with circular saw blades. These are subject to specific design requirements regarding the material selected, the number of sawteeth, cutting speed etc.

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