Blown Film Sample Test

This test will help you review the key concepts in blown film processing. The results will be kept confidential. Each participant will be assigned a confidential identification number. Results will be published by identification number and question.

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Which of the following additives migrate (bloom) to the film surface over time? (Choose as many answers as you wish)

	Antiblock
	Antioxidant
	Antistatic
	Antifog
	Polyisobutylene (cling)
	Ethyl Vinyl Acetate (EVA)

Which of the following types of gels can be eliminated by adjusting the extruder temperature profile so that extruder amps increase? (Choose as many answers as you wish)

	Very small gels that are evenly dispersed and not discolored (known as Applesauce).
	Hollow gels that are evenly dispersed and not discolored (known as Lenses).
	Large gels that are not discolored (known as Arrowheads, Fisheyes, Chevrons).
	Discolored gels (usually brown or black color).

Distortions on the surface of the film are called “Melt Fracture or Shark Skin”. These problems can be reduced by doing which of the following? (Choose as many answers as you wish)

	Increasing the extruder output by increasing screw speed (RPM).
	Decreasing the extruder output by reducing screw speed (RPM).
	Using a narrower die gap.
	Using a wider die gap.
	Cleaning the die lips.

Rotating or oscillating dies will randomize the following types of gauge variation? (Choose as many answers as yo wish)

	Machine Direction gauge variation.
	Transverse Direction gauge variation.
	Both Machine and Transverse Direction gauge variation.
	Gauge variation up to the frost line.
	Gauge variation up to the collapsing frame.
	Cannot ransdomize gauge variation.

Helical instability, also known as "Snaking, Hula Hooping or Mae Westing", can be eliminated by doing which of the following? (Choose one answer from each pair)

	D - Using more LDPE in the formulation
	D - Using less LDPE in the formulation
	E - Using higher melt index formulation (less viscous)
	E - Using lower melt index formulation (more viscous)
	F - Increasing the die gap (wider)
	F - Decreasing the die gap (narrower)

Rolls that exhibit “Starred or Spoked” patterns on the side can be eliminated by doing which of the following? (Choose one answer from each pair)

	A - Increasing film tension as roll gets bigger in diameter.
	A - Decreasing film tension as roll gets bigger in diameter.
	B - Increasing lay-on roller pressure, also known as contact pressure, as roll gets bigger in diameter.
	B - Decreasing lay-on roller pressure, also known as contact pressure, as roll gets bigger in diameter.
	C - Increasing the frost line height.
	C - Decreasing the frost line height.

Congratulation. You have completed the test.