公开(公告)号：US20230219274A1

公开(公告)日：2023-07-13

申请号：US17999977

申请日：2021-06-09

Applicant: 3M INNOVATIVE PROPERTIES COMPANY

Inventor： William W. Merrill ,  Pradeep P. Bhat ,  Francis T. Caruso ,  David L. Hofeldt ,  David D. Nguyen ,  Ziang Li

IPC: B29C48/92 ,  B29C48/32 ,  B29C48/00 ,  B29C48/18 ,  G01B11/06 ,  G01B11/24

CPC classification number: B29C48/92 ,  B29C48/32 ,  B29C48/0018 ,  B29C48/18 ,  G01B11/06 ,  G01B11/24 ,  B29C2948/92152 ,  B29C2948/92704 ,  B29C2948/92904

Abstract: 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.