METHODS AND SYSTEMS FOR MEASUREMENT AND CONTROL OF CIRCUMFERENTIAL LAYER DISTRIBUTION IN BLOWN FILMS

• Main Authors: CARUSO, Francis T, MERRILL, William W, HOFELDT, David L, LI, Ziang, NGUYEN, David D, BHAT, Pradeep P
• Format: Patent
• Language: English; French; German
• Published: 26.04.2023
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; MEASURING; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS; MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS; PERFORMING OPERATIONS; PHYSICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; TESTING; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

A sensing system for measurement of a multilayered blown polymeric film. A feedblock supplies polymeric material streams to an annular blown film die to form a plurality of layers of different polymeric materials. A sensing system is positioned adjacent to a film bubble extruded from the blown film die, wherein the blown film bubble includes annular layers of at least two different polymeric materials. The sensing system emits a signal toward selected circumferential positions around the film bubble and receives a plurality of reflected signals at each circumferential position. Each reflected signal in the plurality of reflected signals is generated at an interface between annular layers that includes a refractive index change detectable by the sensing system. A processor processes the reflected signals from the sensing system, and for each circumferential position determines a layer thickness profile for each polymeric material in the film.