To study how operating conditions affect die lines, screw speed (throughput Q), take-off speed ([V.sub.f]), blowup ratio (BUR) and melt temperature ([T.sub.e]) were varied independently.
We separately altered each of four operating parameters in our film blowing, throughput Q, take-off roll speed [V.sub.f], blowup ratio (BUR) and melt temperature [T.sub.e].
Blowup ratio (BUR) flattens and widens die lines through stretching in the hoop direction.
The blowup ratio
is 6:1 in both MD and TD directions, for an overall stretch ratio of 36:1.
Generally, the second blowup ratio (SBUR) up to 2.5 was achieved.
The open symbols show the change in birefringence of the sample with constant unit second blowup ratio (SBUR).
The company favors a unique bubble shape, in which the film reaches its full blowup ratio
more gradually than in conventional HDPE bubbles.
Aluf's products are run in blowup ratios
from 2:5:1 to more than 3:1 and range in thickness from 0.23 mil up to 7 mil, a testament to the versatility of its product range.
from 1:1 to 5:1 can be used on the same ring, which is aimed at low-stalk processes.