?Plastic Injection Molding is a fast growing process that has gained a lot of
momentum in a very short span of time. There are various advantages of using plastic
injection molding process. The major advantage is that it is very reliable and
cost-effective. Also, this process produces smooth and finished products that require
no further finishing. The equipments involved in plastic injection molding are very
sophisticated and costly. They are known as injection molding machines. The
machinery used are also heavy and some even weigh up to tons of kilogram. But only
when these kinds of machines are used the final product turns out to be a quality
product. This is so because the plastics are fed into these machines and they are
heated until they become fluid. This signifies that the machines should bear up high
temperature and thus comes the requirement of sophisticated equipments.
The plastic when poured, takes the shape of the cavity or the mold used and get
solidified or settled in it. After some time molded material is ejected out from the
cavity. The same cavity can be used to make any?number of molds. The mold can be
of any preferred shape. The mold has two components namely the injection mold and
the ejector mold. The melted plastic resin is transferred into the mold and the ejector
mold helps in ejecting the plastic part after it is solidified in the mold without any
damage using ejecting pins.
The next procedure is the use of hydraulic or mechanical pressure. Air gets trapped
inside the mold and this is done to release the air. This is known as the dwelling
process. The air cavities are pushed to one corner of the mold when pressure is
applied. Then the fluid is allowed to solidify and the mold is cooled. Finally the
solidified plastic part is taken out from the mold either manually or automatically.
The plastic parts experience a change in their physical as well as chemical properties
once the cooling process takes place. The most eminent design contemplation of the
plastic injection molding process is the width of the mold. Usually a mold with a
uniform wall thickness is favored. This helps in reducing the change in mechanical
properties of the plastic part.