method for determining and / or regulation of the orientierungsgrades in blown film lines produced schauchfolien

摘要

For determining and/or controlling the degree of orientation of tubular films which have been produced in a film blowing system consisting of an extruder (1) with film blowing head (2) with internal cooling and lay-flat and take-off devices, the rate of exchanged internal cooling air is controlled as is the extruder speed, the temperature of the extruded plastics material and/or the take-off rate. In order to be able to determine and/or control the degree of orientation in a simple and faultless manner, the bubble shape corresponding to the required degree of orientation is determined in the expansion region and/or set and specified as the desired shape of the bubble (3). The respective actual shape of the bubble is recorded in the expansion region (6), compared with the desired shape and adapted to the desired shape. …IMAGE…