Choosing a Material

When designing a mechanism, different materials are often chosen from which to manufacture the individual components. The purpose of this section is to consider the factors that lead to the choice of a material for a particular component. The body of the electric plug in figure 2.1 is manufactured from a plastics material. One reason for the choice of this material is that it is a good electrical insulator. The pins of the plug must be good electrical conductors. Copper is a good conductor of electricity but it is soft and weak, so brass, which is harder and stronger than copper and almost as good at conducting electricity, is used for the pins.