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