A: PL120101.053
B: PL120100.053
E: 03.93 / T. Weiß
G: 06.93 / T. Weiß
Chapter: 5.3
Page: 2
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Structure and Function
Description of function:
The injection unit is set between the two closing cylinders by
means of the guiding rollers and the two nozzle drive cylinders.
The nozzle drive cylinders are directly connected to the
closing cylinders and have the form of double-action hydraulic
cylinders. The nozzle drive cylinders permit contact of nozzle
and mould as well as access to the nozzle when it is in the
rear end position.
The screw is driven by a slow-action hydraulic motor acting
directly on the injection cylinder piston via a toothed belt.
During the metering process, the injection piston also revolves;
this construction makes it possible to avoid rolling bearings
- which basically would be necessary for the thrust bearing of
the screw - since this function is supplied hydrostatically. At
the same time, the injection piston doubles as a screw
coupling.
The torque of the hydraulic motor can be adapted to the
requirements through selection of the appropriate hydraulic
pressure.
To extend the material life of the screw cylinder heater
bands, heat them regularly, beginning with the first day of
operation, and make sure that they are firmly anchored.
5.3.2 Nozzle change
Preconditions:
1. Eject residual material from screw cylinder.
2. Heat screw cylinder to last preset material temperature.
Process:
1. Pull back nozzle drive cylinder of injection unit to rear
limit stop.
2. Disconnect and dismount nozzle heater band.
3. Unscrew nozzle with suitable spanner.
4. Insert new nozzle; bear in mind that the thread must be
greased with heat-resistant material.
5. Screw in nozzle to limit but do not tighten yet.
6. Mount and connect nozzle heater band.
7. Tighten nozzle after heating to operating temperature.
5.3.3 Instructions for setting - nozzle centre
ATTENTION !
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