Abstract: An oscillating hauloff device for removing blown film from an extruding apparatus has an arrangement of idler rolls for passing film through the unit to provide constant film path length within the hauloff and constant speed of the film exiting the hauloff.

Abstract: An oscillating hauloff device for removing blown film from an extruding apparatus. The oscillating hauloff includes a stacked ring arrangement which provides a compact and stable structure. The turning bars and idler rolls are encompassed in the ring structure and are arranged to cancel effects of web wandering and wrinkling. A method for making the oscillating hauloff, including CNC machining of annealed ring-shaped weldments, that is economical and simple to manufacture. The turning bars are provided with reinforcements that prevent deflection of the turning bars during use. Further the turning bars are provided with flow restricted outlets and axially extending channels to supply uniform air pressure to float the blown film on the turning bars. A specific arrangement for providing utility services to the oscillating hauloff is also disclosed which employs torsional deflection of the loads during rotation of the rings.

Abstract: Automatic thickness profiling for use in blown film and other extrusion lines. The automatic system is integrated into an air cooling ring device either external and/or internal to the bubble or extrusion. The system has or more high resolution circumferentially variable annular air outlets which act to cool the molten resin in a circumferentially variable way. Thin slide plates remain fixed in place except when adjusted to open or close the local annular air outlet by the action of at least one scanning actuator. The actuator is positioned by control signals generated by a control computer which calculates the appropriate local dimension of the variable air outlet in response to circumferential position correlated with thickness variations detected by a film thickness sensor. The film thickness above the frost line is mechanically scanned around the extrusion.