There are many ways to skin a cat, so to speak. Injection molding is a production method for merchandise for use or sale by injecting materials such as metals, glass, elastomers, confections and more commonly thermoplastic and thermosetting polymers into a mold. They are used in the creating of many things and are an ideal way if needing to produce a high volume of the same object.
Jons J Berzelius made the first concentration of polymer from a white crystalline organic acid and a thick, odorless and colorless liquid. He came up with terms like allotrope, isomer, polymer and catalysis for all the different chemicals that he used. He named one such chemical “polymer” that described a natural compound that was made up of the same formula but was different in its molecular weight.
In 1861 the first marketable plastic was made by Alexander Parkes. He named these different materials after himself and in 1862 he gave a show at the International Exhibition in London describing what they could be transformed into. There was a major drawback once these materials were heated and put through the mold and allowed to cool, it was that they seemed to come out very dry and had a tendency to crack.
Later another material was made and was called Celluliod. These were created from using compounds produced that reacted to nitric and sulfuric acids as well as a strong smelling compound known today as camphor. Dyes and other agents were also added.
The whole cycle is very short normally between two seconds to two minutes and consists of four stages. Before the material is injected into the mold it needs to be very securely closed by a clamping unit. Each mould it attached to the molding machine and the top half is allowed to move.
The material then enters the grooves of the screw and is pushed towards the mold as the screw rotates. The molten is injected quickly through a nozzle at the end of the barrel by pressure that has been building up. This pressure lets the material be packed and held in the mold.
As soon as the molten plastics make contact with the interior of the mold surface it will begin to cool down. While cooling down it will solidify into the shape that is required. In some instances certain parts may shrink while cooling but because of the packing of the material in the injection stage this allows more materials to flow reducing shrinkage to a certain degree.
This form of molding has allowed articles to be flexible as well as keeping the strength and finish of the manufactured parts. This also reduced the production time for running these machines. Any off cuts that came out of these molds could be recycled back into usable pellets saving money.
Genevive B. Mata has over 20 years of professional sales experience, 10 of them directly in the plastic pallets and materials handling industry. On her spare time she works on applied-sustainability projects. If you are interested in plastic pallets suppliers, she suggests you check out her friends www.ptm.com/global.