Thermoplastics are organic materials that melt when heated. They should be differentiated from thermoset materials which cure, or become set, when they are heated. Thermoplastic materials melt, which means they are formed when they are in a melted or viscous phase. This generally means they are heated, formed, then cooled in their final shape.
Thermoplastics have a good range of properties and are energy efficient both in their manufacture and processing. Thermoplastic components can be made in very high volume with high precision and low cost. Thermoplastics can replace metals with a considerable weight savings , providing proper care is taken in design. Most thermoplastics have better fatigue properties than metals and will tolerate larger deflections than metals without deforming.