Understanding Plastic Injection Molding- The Process

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Understanding Plastic Injection Molding - The Process
Injection Molding, a technology created in 1940s has revolutionized product design and mass
production because of the flexibility it offers. What is Injection Molding?
It is a process that forces the molten materials into a Mold or a Die. The material takes the physical
properties of the mold's cavity or hollow, after cooling down. Every plastic product you see today
experiences this process. For example, car dashboards, soft drinks caps etc. all experience injection
molding process. The materials can differ such as plastic to metal; anything that is malleable. The
process that uses plastic as a material is known as Plastic Injection Molding.
Plastic Injection Molding - The process
Raw materials: The most widely used raw materials for plastic molding are: Thermosetting
Plastic, Elastomers and Thermoplastic Polymers. These materials are used because they offer
greater viscosity.
Equipment: The basic parts of plastic molding machines are material hopper, heating unit,
plunger etc. The purpose of Presses (a machine part) is to pressurize the molten material into
the hollows or mold's cavity to give the material proper shape. They work in accordance of
Tonnage (It is capability of the machine to apply clamping force, in order to keep the molds in
closed position) Ratings. The tonnage may vary from 5 tons to 6000 tones depending on the
stiffness of the material.
The Process:
Melting:- Injection Molding Machine has a broad and cylindrical melting unit, which
converts the material (polymers) into a liquid state under extreme temperature and pressure.
An auger with an opening at the bottom, receives the polymer or material. With the use of a
hydraulic motor, auger opens into the melting unit. The liquids are restricted from entering
into
the
molds
through
a
valve
system.
Pouring liquefied material into mold cavity or hollows:- After the heating process is
over, the liquid material is poured into Plastic Injection Mold by the auger, to give the
material a desired shape. The molds are pressurized to keep them whole and in correct
position. To make sure no air space is left, the material is poured twice or thrice.
Cooling:- After the molding, the entire mold is introduced to cooling for dense
solidification of the plastic jabs, which exhausts the majority of time of the complete
manufacturing procedure. The cooling is completed by passing air or water over the
frenzied moulds or bringing in cold water through tiny holes on the mould surface.

De-Molding:- Once the cooling procedure is completed, the dense plastic injections are
prepared for removal from the moulds. The clamp on the mould is unlocked to unbolt the
mould and obtain the injection. The whole process is done and the mould is now prepared
for the next unit development.e Code.