HOW DOES INJECTION MOLDING WORK?
In principle, injection molding is simply the process of squeezing liquid plastic into a mold and waiting for it to harden. In practice, however, it’s a little more complicated than that. There is a wide range of material possibilities with injection molding, so the first stage of the process involves selecting an appropriate thermosetting plastic — a material that can be melted, injected and then cooled in order to rapidly form a plastic part. Many materials can be used for this process, including rigid, flexible and rubber-like plastics.
Before the injection molding cycle starts, the material is usually acquired in pelletized form. But before it can be turned into a part, it must be heated and transformed into its molten form. This process is carried out by a heated barrel. The material, stored in a hopper, is forced by a ram into the heated barrel, where it liquifies. It is then pushed toward the mold by a worm gear.
The force from the gear, which is rotated by a motor, moves the molten plastic to where it needs to be. When the material reaches the end of the heated chamber, it is ejected from a nozzle through some thin channels known as runners and into the mold cavity. This is the injection process that gives the process its name.
Because the metal mold is cold, the plastic solidifies almost immediately, forming the final part. This solid part is then removed by opening the mold, allowing for the next shot of plastic to be prepared.
The process can be repeated over and over, until the run is completed or until the mold needs to be replaced. In many instances, replacing the mold will not be necessary, since the molds made from case hardened steel can be used over and over again. At GIA we have the capacity to repair, maintain, service and reproduce molds and or it’s running components at short notice. We also have the ability to produce molds to specification for customers that wish to run their own mold exclusively in our facility.