© MOOG 2010
This document is subject to MOOG INTELLECTUAL AND PROPRIETARY INFORMATION LEGEND . The details are on page II.
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The desired shape of the parison wall profile is commanded digitally by the operator using the display. The
size of the tooling opening or die gap, as measured by a die gap position transducer, is compared with the
operators commanded position as set on the DigiPackⅡdisplay.
The error between the operator commanded position and the actual position caused the servovalve to
control the oil flow to the actuator and reduce the difference between the commanded and actual die gap
opening (position error) to a very small value. This feedback process ensures that the actual die gap
opening follows the commanded die gap opening very accurately.
2-2-8.
PARISON MOLD ALIGNMENT
The Alignment Lines provide a reference line to indicate the parison thickness and the resulting container
wall section after it is blown.
At the alignment lines, the parison is relatively thick and the mold circumference is large. When the parison
is blown, the resulting container wall thickness as measured at the alignment lines is consistent with the
wall thickness measurements of the rest of the container.
If the relative vertical alignment of the parison to the mold is poor, then the wall thickness will not be uni-
form throughout the container and the container must be scrapped.
Figure 2-4
shows the relative vertical position between the parison and the mold. The thicker portions of
the parison are stretched by the blow air pressure to fill the portions of the mold with the greatest cir-
cumference. The act of programming the parison to have its thicker sections in vertical alignment with the
portions of the mold with greatest circumference will produce a container with the desired constant wall
thickness.
Figure 2-4 Good Vertical Alignment Be-
tween the Parison and the Mold.
Figure 2-3 Poor Vertical Alignment Be-
tween the Parison and the Mold
