A schileren system for in-line quality control in a film extrusion process

Bernhard G. Zagar
Abstract:
This paper addresses the problems arising in continuous film extrusion of thin foils that need to result in optical quality but due to process still not completely understood give suboptimal quality of the resultant foil. The foils show more or less severe chatter marks dependent on certain system parameters like feed rate of the product, temperature of the product casted, spinning rate and differential spinning rate of rolls, cooling rate and so on. An inline capable optical quality measurement system is devised that allows to continuously assess the product quality within seconds after the foil is extruded from the casting unit, thus allowing rapid corrective actions if quality declines below a set standard. It also allows for a continuous documentation of the amount of residual chatter marks for each and every inch of product. The system is based upon a schlieren optical setup able to resolve schlieren-caused refraction of collimated light of less than 1 second of arc.
Keywords:
continuous cast extrusion; chatter marks; schlieren technique
Download:
IMEKO-TC14-2007-39.pdf
DOI:
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Event details
IMEKO TC:
TC14
Event name:
TC14 ISMQC 2007
Title:

9th Symposium on Measurement and Quality Control in Manufacturing

Place:
Chennai/Madras, INDIA
Time:
21 November 2007 - 24 November 2007