© MOOG 2019
This document is subject to MOOG INTELLECTUAL AND PROPRIETARY INFORMATION LEGEND . The details are on page II.
4
MRJ06301
④
By controlling the actuator for the core, control the thickness of the parison at the core die gap portion.
⑤
During
②
to
④
, DigiPack
Ⅲ
functions as a digital interface with the PLC of the blow molding machine
and provides information such as the end of the program and the point status of the program sequen-
tially.
1.2.1.2.
Accumurator type molding machines
When used with accumulator machines, the
DigiPack
Ⅲ
controls the parison wall thickness relative to the
accumulator position as the plastic is being extruded.
As the total quantity or volume of plastic extruded is proportional to the accumulator position, then it follows
that the resulting parison wall thickness at any given point on the length of the container must be related
to the accumulator position. Given that the physical properties of the plastic and its temperature are con-
stant from container to con
tainer, then each container’s weight and strength will be consistent.
Figure 1-3
Basic Accumulator Machine Control Diagram
A potentiometer measures the accumulator position and controls the vertical axis of the program display.
The operator can also set the accumulator operating stroke, shot size, and accumulator injection comple-
tion position (cushion). In addition, DigiPack
Ⅲ
also provides interface signals to the machine's PLC for
these functions. After that, the operation of the accumulator is controlled by the PLC.
With an accumulator type blow molding machine, DigiPack
Ⅲ
operates / processes as follows.
①
The operator sets the core position (core die gap opening / closing amount) necessary to obtain the
desired wall thickness (usually constant wall thickness) product on the DigiPack
Ⅲ
controller panel.
②
When the start signal switches from OFF to ON, the DigiPack
Ⅲ
controls the servo valve so that the
core follows the set position according to the position of the accumulator.
③
The servo valve adjusts the flow rate to the core actuator according to the (flow rate) command from
DigiPack
Ⅲ
.
④
By controlling the actuator for the core, control the thickness of the parison at the core die gap portion.
Hydraulics
Die Gap
Tooling
Actuator
PLC Controller
Servovalve
Actuator
DCDT
Position
Accumulator Push Cylinder
Accumulator
Position