PKSC 4300: Blown Film Exam
1. Describe a blown film: - uses a spiral die or spider die
- tube is closed with a nip which keeps the tube inflated
- air is blown on the outside of the tube to cool it
2. What are the parts of the Blown Film Line?: 1) Extruder
2) die
3) Air ring
4) Collapsing frame
5) Nip
6) Winder
3. What are the important properties of blown film?: 1) Thickness and basis weight
2) Tensile properties
3) Crystallinity
4. How does blown film differ from cast film?: - has more gauge variation
- blown film is cooled slower due to using air
- larger crystals form and is more crystalline
5. How are gauge bands removed in blown film?: using a rotating collapsing frame to randomize
the location of the bands on the roll
1. Describe a blown film: - uses a spiral die or spider die
- tube is closed with a nip which keeps the tube inflated
- air is blown on the outside of the tube to cool it
2. What are the parts of the Blown Film Line?: 1) Extruder
2) die
3) Air ring
4) Collapsing frame
5) Nip
6) Winder
3. What are the important properties of blown film?: 1) Thickness and basis weight
2) Tensile properties
3) Crystallinity
4. How does blown film differ from cast film?: - has more gauge variation
- blown film is cooled slower due to using air
- larger crystals form and is more crystalline
5. How are gauge bands removed in blown film?: using a rotating collapsing frame to randomize
the location of the bands on the roll
