Blow molding is a molding process in which air pressure is used to inflate soft plastic into a mold cavity. It is an important industrial process for making one-piece hollow plastic parts with thin walls, such as bottles and similar containers. Since many of these items are used for consumer beverages for mass markets, production is typically organized for very high quantities. The technology is borrowed from the glass industry with which plastics compete in the disposable or recyclable bottle market.
The injection moulding process involves heating & injecting plastic material under pressure into a closed metal mould tool, allowing thousands or even millions of identical parts to be made quickly and cheaply.
The molten plastic cools & hardens into the shape inside the mould tool, which then opens to allow the mouldings to be ejected or removed for inspection, secondary operations or assembly. The process is exained step by step below and you can watch a video of injection mouldings being made at the bottom of the page.