Abstract: An electrostatic charging system holds a film web to a roll without significant slippage, thus allowing for proper tension control of the web even with extreme differences in tension upstream and downstream of the motorized roll. The system can electrostatically transfer a web using motorized drum rolls with an internally integrated web severing knife.

Abstract: A plastic resin extrusion line for the production of blown film includes an external thickness control device that provides a controllable amount of air from an inlet side through an annular region to one or two sets of lips. Barriers that can be manually or automatically controlled are provided in the annular region for localized control of air flow and thus for localized thickness control. The pressure drop across the barriers is significant relative to that in the lips.

Abstract: A blown film die divides a flow of material into two flows with higher and lower flow portions and recombines the flow by combining higher flow portions with lower flow portions. The flow can be divided in circumferential channels between an annular feed ring and an annular distribution ring.

Abstract: A blown film die divides a flow of material into two flows with higher and lower flow portions and recombines the flow by combining higher flow portions with lower flow portions. The flow can be divided in circumferential channels between an annular feed ring and an annular distribution ring.

Abstract: A plastic resin extrusion line for the production of blown film includes an external thickness control device that provides a controllable amount of air from an inlet side through an annular region to one or two sets of lips. Barriers that can be manually or automatically controlled are provided in the annular region for localized control of air flow and thus for localized thickness control. The pressure drop across the barriers is significant relative to that in the lips.

Abstract: An internal bubble cooling air control system in a blown film apparatus has sensors arranged to increase response time and reduce interference, and includes a high speed valve for fast actuation of air flow from a controller in response to signals received from the sensors.

Abstract: A plastic resin extrusion line for the production of blown film includes an external thickness control device that provides a controllable amount of air from an inlet side through an annular region to one or two sets of lips. Barriers that can be manually or automatically controlled are provided in the annular region for localized control of air flow and thus for localized thickness control. The pressure drop across the barriers is significant relative to that in the lips.

Abstract: An internal bubble cooling air control system in a blown film apparatus has sensors arranged to increase response time and reduce interference, and includes a high speed valve for fast actuation of air flow from a controller in response to signals received from the sensors.

Abstract: An internal bubble cooling air control system in a blown film apparatus has sensors arranged to increase response time and reduce interference, and includes a high speed valve for fast actuation of air flow from a controller in response to signals received from the sensors.

Abstract: A blown film die divides a flow of material into two flows with higher and lower flow portions and recombines the flow by combining higher flow portions with lower flow portions. The flow can be divided in circumferential channels between an annular feed ring and an annular distribution ring.

Abstract: An extrusion die has a plurality of die layers stacked one upon the other in a direction generally parallel to the central axis. Each of the layers has an annular flow distribution ring having an outer generally cylindrical surface and an annular feed ring surrounding and engaging the outer surface of the distribution ring. At the engaged surfaces of the feed and distribution ring, the flow from the feed ring is divided into a number of substantially equal flow portions. Seals between adjacent engaged surfaces confine the flow to between the circumferential surfaces of the feed and distribution ring. Half of the flow portions are directed to a recombination region on one side of the distribution ring, and half are directed to a recombination region on the other side of the ring. In recombining, weld lines are formed in high flow areas to minimize the deleterious effect of polymer degradation.

Abstract: An internal bubble cooling air control system in a blown film apparatus has sensors arranged to increase response time and reduce interference, and includes a high speed valve for fast actuation of air flow from a controller in response to signals received from the sensors.

Abstract: A plastic resin extrusion line for the production of blown film includes an external thickness control device that provides a controllable amount of air from an inlet side through an annular region to one or two sets of lips. Barriers that can be manually or automatically controlled are provided in the annular region for localized control of air flow and thus for localized thickness control. The pressure drop across the barriers is significant relative to that in the lips.

Abstract: An extrusion diea plurality of die layers stacked one upon the other in a direction generally parallel to the central axis. Each of the layers has an annular flow distribution ring having an outer generally cylindrical surface and an annular feed ring surrounding and engaging the outer surface of the distribution ring. At the engaged surfaces of the feed and distribution ring, the flow from the feed ring is divided into a number of substantially equal flow portions. Seals between adjacent engaged surfaces confine the flow to between the circumferential surfaces of the feed and distribution ring. Half of the flow portions are directed to a recombination region on one side of the distribution ring, and half are directed to a recombination region on the other side of the ring. In recombining, weld lines are formed in high flow areas to minimize the delitarious effect of polimer degredation.

Abstract: An extrusion die with a plurality of die layers stacked one upon the other in a direction generally parallel to the central axis. Each of the layers has an annular flow distribution ring having an outer generally cylindrical surface and an annular feed ring surrounding and engaging the outer surface of the distribution ring. At the engaged surfaces of the feed and distribution ring, the flow from the feed ring is divided into a number of substantially equal flow portions. Seals between adjacent engaged surfaces confine the flow to between the circumferential surfaces of the feed and distribution ring. Half of the flow portions are directed to a recombination region on one side of the distribution ring, and half are directed to a recombination region on the other side of the ring. In recombining, weld lines are formed in high flow areas to minimize the deleterious effect of polymer degredation.

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.

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. It comprises one 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.