Development of an Automatic Laser-Based Film Inspection Test Method, 1997 Polymers, Laminations & Coatings Conference Proceedings

Inspection of plastic films for defects by a laser scanning device can provide a timely and unbiased evaluation, thereby affording a more precise grading system which could eliminate scrap material. A test method, including calibration procedures and operation parameters, has been developed for an automatic laser-based instrument to size and count defects (gels) accurately and reproducibly in thin, transparent films. Test method performance is described for a LDPE thin film. In static tests, the laser sized the gel accurately within the rated resolution of the equipment. The accuracy was also proved in dynamic tests. Furthermore, the precision of laser gel counts in a LDPE resin under standard film fabrication conditions varied by < 15%="" in="" total="" gels="" for="" the="" same="" resin="" run="" on="" five="" different="" days.="" this="" type="" of="" analysis="" is="" performed="" in="" order="" to="" establish="" specifications="" on="" gel="" counts="" for="" a="" given="" resin="">