The
structure of the hot runner mold is generally the same as that of the thin
nozzle. The biggest difference is that the runner is located in one or more hot
runner plates and hot nozzles with constant temperature. There is no cold
material demoulding, the runner and gate are directly on the product.
Therefore,
the runner does not need to be demolded. This system is also known as the
nozzleless system, which can save raw materials. It is suitable for the product
that the raw materials are expensive and the product requirements are high.
Hot
runner system, also known as hot sprue system, is mainly composed of hot runner
sleeve, hot runner plate and temperature control electric box. There are two
types of hot runner system: single point hot sprue and multi-point hot sprue.
Single-point
hot sprue is to use a single hot sprue sleeve to inject molten plastic into the
cavity directly. It is suitable for plastic molds with single-cavity and
single-gate; multi-point hot-gate is to branch the molten material to each
through hot runner plate. It is suitable for single cavity multi-point feeding
or multi-cavity mold.
Advantages of hot
runner systems
1.
No regrind material, no post-processing is needed, the entire molding process
is fully automated, saving working time and improving work efficiency.
2.
Low pressure loss. The hot runner temperature is same as the nozzle temperature
of the injection molding machine, which avoids the condensation of the raw
material on the surface of the runner and reduces the loss of injection
pressure.
3.
Reuse of regrind material can improve the degradation of plastic performance,
while the use of hot runner system without nozzle materials can reduce the
consumption of raw materials and thus reduce product costs.
4.
In the cavity, the temperature and pressure are uniform, the plastic parts have
low stress and uniform density, and the molding in series is continuous under a
small injection pressure. For transparent parts, thin parts, large plastic
parts or highly demanding plastic parts, it can show its advantages, and can
produce bonded products with a small number of sheets.
5.
The thermal nozzle adopts standardized and serialized design and adopts various
alternative nozzle tips, which has good interchangeability. Uniquely designed
and processed electric heating coil can achieve uniform heating temperature and
replace long.
Disadvantages of Hot
Runner System Applications
1.
The overall mold closing height is increased, and the overall height of the
mold has increased due to the installation of hot runner plates.
2.
Heat radiation is difficult to control. The biggest problem of hot runner is
the heat loss of runner, which is a major problem to be solved.
3.
There is thermal expansion, thermal expansion and contraction are issues to be
considered in our design.
4.
The increase of mold manufacturing cost and the high price of standard
accessories of the hot runner system have affected the popularity of hot runner
molds.
From
weizhushu
Grandshine
is a vertically integrated plastic injection molding manufacturer. From product
design to the manufacturing of complete plastic products,we are a one stop
source for all your plastic contract manufacturing needs.Plastic injection
molding for special project and OEM/ODM product solution are available.
www.grashine.com
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