In an injection molding method molten plastic is injected into a mold at high pressure to get a desired part. The molds are made from steel or aluminium. Injection molding is widely used in automobile industry. The most commonly used thermoplastic materials are polystyrene.

The process cycle
Before the injection of the material to the mold the two halves of the mold must be securely closed in the clamping unit. The clamping unit is hydraulically powered. The plastic material is melted by heat and pressure then injected very quickly into the molds. The injection time can be estimated by the shot volume, injection pressure, and injection power. The molten plastic begins to cool and it will solidify into the desired shape. After sufficient time has passed, the cooled part may be ejected from the mold by the ejection system, which is attached to the rear half of the mold. When the mold is opened, a mechanism is used to push the part out of the mold. Force must be applied to eject the part because during cooling the part shrinks and adheres to the mold.
Injection molding is also used in security custom packaging by integrating RFID technology and packaging. It helps in creating theft-deterring containers that surround assets such DVDs, CDs and Software to create locked barrier.