© MOOG 2019
This document is subject to MOOG INTELLECTUAL AND PROPRIETARY INFORMATION LEGEND . The details are on page II.
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MRJ06301
1-5-5. CUSTOMER SUPPLIED CYLINDER REQUIREMENTS
The customer supplied cylinder is required to control the die gap motion in blow molding extrusion heads.
As such their purchase specification must include: Low friction, long life piston and rod seals; Robust rod
bearings capable of absorbing large potential side loads and high temperatures. A quality cylinder must
be purchased to meet these requirements.
The mounting provisions for the tooling actuator shall include: a strong mounting structure, provisions for
axial and parallel alignment of the tooling actuation rod (mandrel) with the die gap actuators rod, provisions
to allow the actuator stroke center and the tooling’s effective stroke center to coincide, tooling motion stops
to protect the tooling and/or extruder.
Some actuators with an anti-rotation feature require the nut torque loads on the anti-rotation
device to be limited by absorbing the tightening torque with a wrench on the actuator rod flats.
1.5.5.1.
MANIFOLD
The manifold must be mounted using as close as possible to the cylinder. Ideal methods are to mount the
manifold directly on the c
ylinder, sealing the ports with “O” rings or to use tubing between the cylinder and
manifold.
The pressure and return connections should be straight thread fittings using an “O” ring as a seal. Tapered
thread fittings are not encouraged as they tend to leak and when they are torqued up to stop the leak, the
servovalve mounting surface is distorted, causing leakage at the servovalve-manifold seal. Straight thread
fittings using “O” rings do not leak or cause mounting surface distortion.
Should tapered thread fittings be used, ONLY Teflon tape can be used on the tapered threads as a sealant.
The Teflon tape must not cover the last two threads at the smaller diameter portion of the thread. Any other
material will cause eventual contamination problems.
Figure 1-7 shows two possible methods of adjusting the positional relationship between the tooling actu-
ator and the tooling die gap closed position. Tooling motion stops may be required to limit the forces on
the die gap tooling when the die and mandrel touch.
“Figure 1-9” is a typical installation.
Tooling motion stops may also be required to insure a die gap opening on a continuous molding machine.
An inadvertent closure of the die gap could cause very high pressures in the extruder barrel and extrusion
head and result in their damage and/or failure. The above comments must be considered for the proper
installation of either a Moog supplied die gap tooling actuator or a customer supplied actuator.
1.5.5.2.
SERVOVALE MOUNTING
The servovalve is mounted to a manifold with four mounting
screws and using four “O” rings to seal the Pressure, Return
(Tank), and the two Cylinder hydraulic connections.
The “O” ring seal between the servovalve and manifold depends
upon the servovalve mounting manifold surface flatness to insure
that there are no oil leaks. This surface must be flat within
0.025mm and have a √32 RMS finish.
Two servovalves mounting patterns are available: a Cetop 5, NG
10 or a Ø22,2mm, Moog 76 port circle.
Figure 1-10 G631-XXX Servo-
valve
