Just before the pellets are melted, they are combined with special pellets of concentrated color. These melt with the plastic and allow many colors to be molded from the same pellets of plastic.
The mixture of plastic and color pellets get fed into the injection module which is basically a screw that turns inside a tube. This screw squishes and squeezes the pellets with a lot of friction and pressure. Then we turn up the heat to melt and further mix the pellets to form uniformly colored, molten plastic.
As the screw turns the melting and mixing are completed, and an accurate measure of the near liquid plastic is ready for injection. The screw then stops turning and slides forward in the barrel, forcing the molten plastic through a small opening called a gate. This action requires a huge amount of force to hold the mold closed-between 350 tons of pressure for our small items and 1500 tons of pressure for our large items.