What is The Injection Molding Technique of Making PET Bottles?

PET bottles are indeed the most popular types of bottles used globally nowadays. The benefits associated with them are easy production, greater durability, convenient packaging, ease of transportation, and eco-friendly nature. These benefits have contributed a lot in making the PET bottles widely acceptable. They are primarily made of polyethylene terephthalate, a thermoplastic polymer from the polyester family. The use of this polymer has given them their name: PET. The industries that make extensive use of PET are beverages, mineral water, wine, chemicals, and pharmaceuticals, among others.

These bottles are required to be manufactured in huge numbers owing to their high demand across various industries. Needless to say, a quick, effective and economical manufacturing technique would be required for such bulk production. That technique is the injection molding technique. As the name suggests, this technique involves the use of moulds of various shapes and sizes. The plasticmold manufacturers and steal mold manufacturers get their biggest orders from PET bottle plants.

Let’s discuss about the injection molding technique. This technique of manufacturing PET bottles makes use of PET pellets, which are actually plastic granules or small tablets of plastic. These pellets are melted to form a plastic resin, which is filled into a mould cavity. Afterwards, this molten plastic is left to naturally cool inside the mould. After cooling, the resin takes the form of what is called, a PET preform. The preform so made possesses the texture and contour impressed upon it by the mould. The majority of moulds are made of tool steel, but the stainless steel molds are considered better.

The injection molding method further has two sub divisions, viz., one-step method and two-step method. In the one-step method, PET preform, which was made inside the injection mould, is inserted in the blow-molding compartment of the same machine. The preform turns into a PET bottle inside this compartment. This method is energy efficient and it is mostly adopted by small production units.

In the two-step method, the preform made inside the injection mould is introduced into another machine, which is used for stretch blow molding. Before inserting the preform into this machine, it is heated all over again to make it elastic. Then, the preform is blow moulded inside the machine to make it into a bottle. However this method is somewhat costly, it is considered the best for bulk production and it offers higher flexibility. It is widely practiced by the medium and large scale production facilities.

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.

Whichever bottle manufacturing method you may choose out of the two divisions of the injection blow moulding technique, you must select a high quality mould to create high quality PET bottles. Acme Disys is a know name in the bottlemoulds industry from where you can source various types of molds.