Injection moulding forces molten polymers into moulds to make intricate/ detailed designs; extrusions are a continuous process constantly making the same simple, cross-sectional design and cutting to size
Injection moulding and extrusion are both manufacturing processes used to shape plastic and other materials, but they differ in how they work and the types of products they create.
- Injection Moulding
- Process: Plastic is melted and injected into a mould under high pressure. Once the material cools and solidifies, the mould is opened, and the part is ejected.
- Best for: Creating complex, detailed, and precise 3D shapes.
- Common Products: Plastic housings, bottle caps, automotive parts, medical devices, toys.
- Key Characteristics:
- Requires moulds, which can be expensive.
- Produces high-quality, repeatable parts.
- Works best for high-volume production.
- Extrusion
- Process: Plastic is melted and continuously pushed through a shaped die, forming a long, continuous profile. The extruded material is then cut to the desired length.
- Best for: Producing long, uniform cross-section products.
- Common Products: Pipes, tubing, window frames, plastic sheets, insulation coating for wires.
- Key Characteristics:
- Continuous process, making it efficient for long parts.
- Lower tooling costs than injection moulding.
- Limited to products with a consistent cross-section.
| Feature | Injection Moulding | Extrusion |
| Shape Complexity | Complex 3D Shapes | Simple, uniform profiles |
| Process Type | Discrete (batch-based) | Continuous |
| Tooling Cost | Higher | Lower |
| Efficiency | Best for mass production of detailed parts | Best for long, continuous products |
| Product Examples | Toys, cars, parts, medical devices | Pipes, tubes, plastic sheets |