METHOD AND DEVICE FOR CONTROL OF THE THICKNESS OF EXTRUDED FILM

The present invention relates to a process for the automatic control of the thickness of extruded film ( 8 ). The purpose of the invention is to lower the deviations in the thickness of the film more quickly after the start of the extrusion process. The process involves the measurement of the thickness profile of the film just extruded ( 8 ) by means of a thickness-measuring probe ( 12 ). The thickness-measuring probe ( 12 ) is moved along the surface of the film substantially perpendicular (x) to the conveying direction (z) of the extruded film ( 8 ). The thickness-measuring probe ( 12 ) records for each measuring cycle (MZ) a thickness profile (P) of the film ( 8 ) at least over parts of the expansion of the film ( 8 ) perpendicular (x) to its conveying direction (z). The process pursuant to the present invention is characterized by the fact that during a predetermined time-frame at the start of the extrusion process measured values or information derived therefrom using or for a greater number of measuring cycles is made accessible to the computer ( 14 ) than those recorded by the thickness-measuring probe ( 12 ) in a time-frame of similar length during the normal operation and that the computer ( 14 ) takes into account these measured values while providing the statistical values.