Fundamentals of Injection Moulding Materials
The selection of optimal injection moulding materials is critical to the success of any plastic manufacturing project. These materials must be carefully chosen based on mechanical requirements, environmental conditions, aesthetic needs, and cost considerations. The most common injection moulding materials are thermoplastics, which can be repeatedly melted and solidified without significant degradation of their properties.
Injection moulding materials typically start as small pellets that are fed into the injection moulding machine. These pellets are heated until molten and then injected under pressure into a mold cavity. The choice of materials significantly impacts the final product's characteristics, including strength, flexibility, chemical resistance, and appearance. Understanding material properties is essential for designers and engineers working with injection moulding materials.
Material Categories and Properties
Thermoplastics
Most common materials that soften when heated and harden when cooled. Can be recycled and remolded multiple times. Examples: ABS, Polycarbonate, Nylon.
Thermosetting Plastics
Undergo chemical change when heated, creating permanent bonds. Cannot be remelted. Examples: Epoxy, Phenolic, Silicone.
Elastomers
Rubber-like materials with high elasticity and flexibility. Ideal for seals, gaskets, and flexible components. Examples: TPE, TPU, Silicone rubber.
Engineering Plastics
High-performance materials with superior mechanical and thermal properties. Examples: PEEK, PPS, PEI - used in demanding applications.
Common Materials Comparison
| Material | Tensile Strength | Max Temp (°C) | Cost | Primary Applications |
|---|---|---|---|---|
| ABS | 40 MPa | 80 | Low | Consumer products, automotive |
| Polypropylene | 35 MPa | 100 | Low | Packaging, containers |
| Polycarbonate | 70 MPa | 135 | Medium | Optical, safety equipment |
| Nylon 6/6 | 85 MPa | 120 | Medium | Gears, bearings |
| PEEK | 100 MPa | 250 | High | Aerospace, medical implants |
According to industry research, the global market for injection moulding materials is projected to reach $280 billion by 2028, with engineering plastics and sustainable materials showing the strongest growth. Material innovation continues to expand applications across industries.
Material Selection Factors
Mechanical Properties
Strength, flexibility, impact resistance, and fatigue characteristics
Thermal Properties
Heat deflection temperature, thermal expansion, and conductivity
Chemical Resistance
Compatibility with chemicals, solvents, and environmental factors
Cost Considerations
Material cost, processing requirements, and tooling implications
