Why Measure Components

Component measurement can be used for a number of purposes, the most frequent being:

To make sure that a component being developed conforms to set parameters. For example, if a plastic part has to interact with others, e.g. as part of a complex assembly, then it must fall within predetermined tolerances.
To see how an existing product is performing as it is subjected to use
To ‘reverse engineer’ an existing component. Measurements are used to create an accurate drawing (such as a 3-Dimensional CAD file) from which additional components can be manufactured.
To make sure that a measurement device (such as a digital Vernier), jig or gauge that is used to monitor the dimensions of parts in production is within tolerance. This is called fixture verification