What is injection molding?

During injection molding, plastic granules are heated to their melting point and then forced under pressure into metal molds where the molten plastic hardens into a designated shape. The mold then opens and the newly formed part is removed and inspected, ready for shipment or secondary manufacturing operations. Cycle time is relatively short and large quantities of parts can be produced quickl. Some tools will produce multiple identical parts reducing even further the amount of time needed for mass production making injection molding a very efficient process. 

There are some alternatives to injection molding such as thermoforming or vacuforming, die stamping, extrusion, blow molding, and machining.

The advantages of injection molding are many. Injection molded parts will have good mechanical properties such as strength-to weight ratio, low mass and good surface appearance.

Altough the initial investment for injection mold can be  higher than the previously mentioned processes, the main advantage of injection molding is  the low unit cost, especially when the volumes are high.