Heißkanaldüsen Typ SLT/-DLT Customer information

Heißkanaldüsen Customer information Typ SLT/-DLT
Vliesolen – Bamboo Fibre Reinforced Plastics
The firm of PMG Geotex in Chemnitz compounds
plastics with exotic filling materials.
Instead of the usual glass fibres special, they use
bamboo fibres to modify the properties of polypropylene
or polyethylene, for example. Depending on their length,
the bamboo fibres can be used in different areas. For
example, longer fibres are mixed into screed or concrete
to prevent cracks forming during drying. The shorter
bamboo fibres are compounded into plastics as
reinforcement or filling material.These fibres, which are
chemically linked with the polymer, make the plastics
much stronger than those that are not reinforced. In
addition this filling material also has an impact on the
price of the product.
The properties of a PP modified with 30% bamboo fibres
rank between unreinforced polypropylene and
polypropylene that is reinforced with approx. 20% glass
fibre.
There is no problem in processing these plastics
conventionally with cold runners. However, more and
more interested parties ask about the possibility of
processing this material with hot runners too.
The trials carried out by PMG and GÜNTHER
Heisskanaltechnik GmbH together show that it is
possible to process plastics filled with bamboo fibres with
hot runners also.
Three plastics (PP, PE–LD /PE-HD), each with 30%
bamboo fibres, were available for the processing trial:
- Vliesolen BF30, natural (PP-2/30-HM1)
- Vliesolen BF30, black (LDPE-2/30-HS2)
- Vliesolen BF30 (HDPE-1/30-HM1)
These materials were tested in a test mould
(2-cavity: 1-gr washer), which was equipped alternatively
with
- nozzles of tip (5SHT50S) or
- valve gate nozzles (5NHT50LA
Small sprue gates are not suitable because the bamboo
fibres are longer than glass fibres and there is a risk of
the sprue gate getting clogged up with fibres.
If the injection gate diameter is 1.6 mm (5SHT50) or 1.4
mm (5NHT50LA), the above types of materials can be
processed without restriction.
www.guenther-hotrunner.com
7/12 Subject to technical changes
The hot runner nozzles used in the test feature a two-part
shaft in the front area of the nozzle. This structural feature
provides excellent thermal isolation between the hot
runner nozzle and the mold. This thermal separation also
has a positive effect on the temperature control inside the
nozzle. The hot runner nozzles are suitable for
processing standard, engineering and high temperature
plastics. When processing filled plastics, nozzle tips
made of a hard metal alloy with good heat conductive
properties provide very good wear protection.
Material tube
(25 W/mK)
Heater
Air
(0,04 W/mK)
Gap solidified
plastic
(0,2...1,2 W/mK)
iA
Fig. Standard hot-runner nozzle
5SHT50 with two-component
shaft (patented).
Nozzle with excellent insulation
in the front shaft area.
Picture: The two-stage shaft of the SHT type nozzle and the frozen
plastic material which forms a "cap" around the nozzle provide for
optimized isolation towards the cavity and therefore produce a
homogeneous temperature profile in the nozzle.
Valve gate nozzles can be recommended to achieve
flash-free gate quality of the part. These nozzles are
characterized by a long lifetime and short cycle times in
operation.
Melt
Shaft made of
titanium alloy
(7 W/mK)
Open nozzle tip
(100 W/mK)
For any questions, please contact our Application Engineering department at + 49 (0) 6451 5008-31 or -63.
The information is given in accordance with our present-day knowledge and is meant to provide technical background.
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