Cooling and thickness control for extruded products

摘要: 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 (24) and/or internal (30) to the bubble or (22). It comprises one more high resolution circumferentially variable annular outlets (62) which act cool molten resin a way. Thin slide plates (72) remain fixed place except when adjusted open close local outlet by action of at least scanning actuator (99). positioned control signals generated computer (106) calculates appropriate dimension response circumferential position correlated with variations detected sensor (102). above frost line mechanically scanned around extrusion. In case making products cooling, counteracting adjustments are made as flow areas changed maintain constant entrapped volume. novel actuation also shown be useful locally adjusting finely segmented lip. A method correlating changes respective zones disclosed.