Cast Film Trouble Shooting Guide

Problem Possible Cause Possible Solution
Non uniform film thickness Poorly adjusted die gap Reset die lip opening
Non uniform air flow from air knife Adjust air knife opening
Non uniform die temperature profile or defective thermocouple or heater Reset temperature profile or replace faulty device
Lines/Stripes (in machine direction) Poorly adjusted die gap or heater zones Reset die lip opening or adjust die temperature profile
Material hanging up in die interior Ream die to purge trapped material
Non uniform casting roll temperature Change roll temperature or coolant velocity to provide uniform surface temp
Dirty or marred casting roll Clean or replace defective roll
Bands/Lines (in transverse direction) Haul off speed fluctuating Check drive system and draw ratios between machine segments
Extrudate not releasing from casting roll Inspect roll surface for contaminants or change roll temp to ensure uniform release
Sticking to casting roll Reduce melt temp or casting roll temp
Wrinkles Improper casting roll temperature Increase roll temperature to increase adhesion to casting roll
Draw ratios not adjusted properly Reset roll speeds
Rough film surface Die or melt temperature too low Increase die or melt temp
High haze Film cooling too slow Reduce casting roll temp or reduce line speed
Low gloss Improper or inadequate mixing Modify temperature profile and increase back pressure