Hot runner nozzle - Günther Heisskanaltechnik ...

Fig. Nozzle installed in a retracted position
Within the framework of permissible processing
parameters, the smallest possible gate diameter means:
small gate diameter
Fig. Reducing the gate diameter
Fig. Vacuoles under the gate
1.4. 11
iT
ØD
L + L + 0.02
tool temperature
processing temperature
This is the point at
which the material
solidifies at last.
Gating
Reworking the gate
With gate diameters smaller than
ØD = 1.2 mm, the nozzle must
beinstalled further back.
You will find a Delta Tool calculation
program on our homepage at
www.guenther-hotrunner.com
available for download free of charge.
Reducing the gate diameter
The gate diameter cannot be
arbitrarily reduced. The smallest
permissible diameter is dependent
on the material used.
Furthermore, the gate size is also influenced
by the mold temperature
and processing temperature.
Vacuoles under the gate
Direct gating with a hot runner system
can produce vacuoles under the
gate.
Remedy:
Longer holding pressure time to
compensate for shrinkage.
Gate diameter for fibre reinforced
materials
The gate diameters for glass fibre
reinforced materials or materials
containing additives (flame retardants,
heat stabilisers) 0.2 to 0.3 mm
larger. The same applies to multi-tip
nozzles.
www.guenther-hotrunner.com
Subject to technical changes 4/11