Which process is described as similar to extrusion but forces heated granules into a mould?

Which process is described as similar to extrusion but forces heated granules into a mould?

• A. Injection moulding
• B. Extrusion
• C. Blow moulding
• D. Rotational moulding

Answer: (A)

Injection moulding is the process described. It starts by heating plastic granules until they melt, then a screw pushes the molten plastic under high pressure into a closed mould. The mould defines the final shape, and the part is cooled and ejected. This mirrors extrusion in that the material is heated and moved forward, but it differs because extrusion pushes the melt through a die to form a continuous profile, not into a mould to make a discrete part. Blow moulding forms hollow shapes by inflating a heated preform inside a mould with air, while rotational moulding builds hollow parts by melting material inside a rotating mould rather than injecting it.

Injection moulding is the process described. It starts by heating plastic granules until they melt, then a screw pushes the molten plastic under high pressure into a closed mould. The mould defines the final shape, and the part is cooled and ejected. This mirrors extrusion in that the material is heated and moved forward, but it differs because extrusion pushes the melt through a die to form a continuous profile, not into a mould to make a discrete part. Blow moulding forms hollow shapes by inflating a heated preform inside a mould with air, while rotational moulding builds hollow parts by melting material inside a rotating mould rather than injecting it.