A Brief Introduction to the Injection Moulding Technique of Making PET Bottles
PET
bottles are one of the most popular types of bottles used worldwide
today. Their attributes such as easy production, high durability,
easy packaging, easy transportation, and easy recycling, have
contributed a lot in making these bottles so popular. They make use
of polyethylene terephthalate, a thermoplastic polymer from the
polyester family; the use of this polymer is also behind these
bottles christened PET. The industries that make use of PET the most
are beverages, mineral water, wine, chemicals, and pharmaceuticals,
among others.
These
bottles need to be produced in bulk owing to their high demand across
various industries. Naturally some quick, effective and economical
technique would be required for such production. That technique is
the injection molding technique. As the name suggests, this technique
make use of moulds of various shapes and sizes. The mould making companies in South Africa,
India, China, and various other countries, witness the greatest
demand for their products in the PET manufacturing industry.
Now
coming to the technique itself; the injection moulding technique of
PET bottle manufacturing makes use of PET pellets, which are
basically plastic granules or small plastic tablets. These pellets
are melted to form a plastic resin, which is then inserted into a
mould cavity. The molten plastic is then left to cool inside the
mould through natural process. As the resin cools down, it assumes
the form of the PET preform, possessing the texture and contour as
per the mould. Most of the moulds are made of tool steel, but the
stainless steel moulds are deemed superior.
The
injection molding method also has two sub divisions, namely: one-step
method and two-step method. In the one-step method, PET preform, made
inside the injection mould, is introduced in the blow-molding
compartment of the same machine. The preform is converted into a PET
bottle inside this compartment. This method saves energy and it is
mostly used by small factories.
Then,
there is the two-step method in which, the preform made inside the
injection mould is introduced into a separate machine meant for
stretch blow molding. Before putting the preform inside this other
machine, it is reheated to make it elastic. After that, the preform
is blow moulded inside the machine to provide it the shape of a
bottle. Though this method is relatively costlier, it is considered
good for bulk production and provides more flexibility. Therefore,
the medium and large scale production facilities widely use this
two-step method.
Irrespective
of the method that you use under the injection moulding technique,
one thing remains important: the quality of mould. If the mould is of
good quality, then the final product, i.e., the PET bottle, will also
be good and vice-versa.
Acme
Disys is a leading supplier of high precision pet preform and cap
molds. The company caters to various industries such as beverages,
packaged water, edible oil, and pharmaceuticals. They have over a
decade of experience into the Pet Preform Mold Industry.
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