That we use in our daily life and
production to the various tools and products, to the base of the machine tool,
the fuselage shell, small to a germ head screws, buttons, and all kinds of
household appliances shell, which has close relation with the mould. The shape
of the die decides the shape of the products, precision mold processing quality
and determines the quality of these products. Because the material of all kinds
of products, appearance, specifications, and different purposes of mould into
casting die, forging die, die-casting mould, stamping mould of plastic moulds,
such as, and plastic moulds.
In recent years, with the rapid development
of plastic industry and general engineering plastics in the aspects of
improving strength and precision, the application range of the plastic products
are also constantly expanding, such as household appliances, instrumentation,
construction equipment, automotive industry, daily hardware, and many other
fields, proportion of plastics is rapidly increasing. A reasonable design of
plastic parts often can replace more traditional metal pieces. Industrial
products and daily products rising trend of plastic.
more information www.chinamoldmaker.org www.cnmoulding.com
Injection molding is the most widely used
method in plastic processing. This method is applicable to all thermoplastics
and part of thermosetting plastics, plastic products made the great number of
them is the other forming methods of dust, as the main tool of injection molding
processing, one of the injection mould, the quality of precision, manufacturing
cycle and injection molding production efficiency in the process of the level
of high and low, directly affect the product quality, yield, cost and product
updates, at the same time also determines the enterprise in the market
competition ability and speed of reaction.
Injection mould is made up of several steel
plate with various parts, basic is divided into:
A forming device (die, die)
B positioning device (guide pin, guide
sleeve)
C fixtures (h board, code die hole)
D cooling system (hole)
E thermostatic system (heating tube, hot
line)
F runner system (pumping of nozzle hole
flow channel slot and port holes)
G ejection system (thimble, top stick)
5, depending on the system of pouring
system type of mould can be divided into three categories:
(1) the gate of mould, the runner and gate
on the parting line, together with the product in the mould stripping, the
simplest design, easy processing, low cost, so more people using gate system
operation.
(2) nozzle mould: the runner and gate is
not the parting line, generally directly on the product, so to design a set of
shuikou parting line, design is relatively complex, processing more difficult,
often depending on the product requirements to choose fine runner system.
(3) the hot runner mold: this kind of mold
is approximately the same structure and fine shuikou, the biggest difference is
that flow into one or more of the temperature of heat flow but and heat pumping
mouth, no cold feeding demoulding, runner and gate directly on the product, so
the port don't need mold release, also known as no runner system, this system
can save raw materials, applicable to the raw material is more expensive, high
requirement of products, design and processing difficulties, mould cost is
high. Hot runner system, also called hot runner system, mainly composed of hot
runner, hot water but, temperature control box. Our common hot runner system
there is a single point of hot runner and hot runner 2 more forms. Single point
gate is to use a single hot runner of the molten plastic into the cavity
directly, it is a single cavity of a single gate of plastic mold; Multipoint
hot runner by hot water but the molten material branch to various points in the
hot runner set into the cavity, it is suitable for single cavity more into the
material or multi-cavity mold
The advantage of hot runner system
1) material floolwing does not need after
processing, the whole forming process is fully automated, save the working
time, improve work efficiency.
(2) the pressure loss is small. Hot runner
temperature and the temperature of the plastic injection machine nozzle is
equal, to avoid the surface of the material in the runner, condensate loss in
injection pressure.
(3) material floolwing repeated use can
make plastic performance degradation, and the use of hot runner system is not
shuikou expected, can reduce the loss of raw materials, thereby reducing the
product cost. Uniform temperature and pressure in the cavity, plastic stress is
small, uniform density, in smaller injection pressure, the shorter the forming
time, injection molding injection system is better than the general products.
For transparent, thin pieces, large plastic parts or high demand parts can show
its advantage more, and with small models produce larger products.
(4) hot nozzle adopt standardization,
seriation design, equipped with a variety of selection of the nozzle head, good
interchangeability. Unique design and processing of electric heating circle,
can achieve uniform heating temperature, long service life. Hot runner system
is equipped with heat flow but, thermostat, etc., the design is exquisite,
species diversity, use convenient, stable and reliable quality.
Application of hot runner system
deficiencies
(1) the whole mould height increasing, by
adding hot water but, mold the overall height increase.
(2) the thermal radiation is hard to
control, is the biggest trouble of hot runner gating heat loss, is a major
issue to solve.
(3) thermal expansion, heat bilges cold
shrink is to consider when we design problem.
(4) the mold manufacturing costs have gone
up, hot runner system standard accessories price is higher, affect the
popularity of hot runner mold.
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