Coefficient of linear expansion

The coefficient of linear expansion, symbolised by the Greek letter α, is an essential physical concept that describes the relationship between the temperature change ΔT in kelvin (K) and the resulting relative change in length ΔL of a given dimension L. In short, it shows us how the length of an object changes when its temperature changes. This change is proportional to the temperature change.

In practice, this means that an object with a particular coefficient of linear expansion changes by a particular relative length when its temperature changes by one unit. It is important to note that this coefficient is not constant, but can differ from material to material. For example, in injection-moulded parts, the coefficients of linear expansion can vary along and across the direction of flow. This means that the material expands or contracts differently depending on its orientation when it is heated or cooled.