Which high‑volume manufacturing process where molten plastic is injected into a mould under pressure?

• A. Casting
• B. Injection Moulding
• C. Extrusion
• D. Forging

Answer: (B)

This item tests understanding of a high‑volume plastic shaping method that injects molten material into a mould under pressure. In injection moulding, plastic pellets are melted in a heated barrel, and a screw or plunger forces the molten resin into a closed mould at high pressure. The mould defines the final shape, and the part solidifies as it cools, ready for ejection. The process is ideal for high‑volume production because cycle times are short and moulds can be used repeatedly with automation, delivering consistent parts with good surface finish and tight tolerances.

Other methods don’t fit this description: casting involves pouring liquid material into a mould rather than injecting it under pressure; extrusion pushes molten plastic through a die to make continuous shapes, not final 3D parts; forging shapes material by deformation, typically metal, not by injecting plastic into a mould.