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Cast Film - Air Knives

Modified on Saturday, 31 January 2015 11:14 PM by mpieler Categorized as Consultants Corner
Cast film - air knives
Vol. 25 #3, December 1998

When casting film, the air knife lips should usually be within 1/16" to 3/16" away from the film just after the film impinges on the chill roll. If it is farther away, the pinning pressure is reduced because the air coming out of the air knife diffuses beyond that distance. Furthermore, the air knife should be directed just slightly away from the die to avoid cooling the die. Too much of an angle and too large a gap will cause the web to flutter.

- Bill Foerster, XtruTec Engineering

See also:
  • Casting of extruded semi-crystalline film and sheet
  • Chrome plated steel casting drums
  • Film and sheet pinning techniques to promote heat transfer to cooling rolls

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