Which process uses air to shape the plastic?

• A. Vacuum Forming
• B. Injection Moulding
• C. Extrusion Moulding
• D. Blow Moulding

Answer: (D)

Blow moulding uses air to shape the plastic. In this process, a heated plastic tube or parison is placed in a mold and air is blown into it, forcing the plastic to inflate and press against the mold walls. This creates hollow, uniform-walled shapes like bottles and containers, ideal for high-volume production. The other methods don’t rely on internal air pressure: vacuum forming pulls a sheet into a mold with suction, injection moulding injects molten plastic into a mold to fill it, and extrusion-based methods push molten plastic through a die to form continuous shapes.