What is Precision Engineering?

Precision Components

This seems like such a simple question yet it is often blurred or confused by various quotes and uses of the term precision.


Broadly speaking, the classic definition of Precision Engineering is an accuracy of 1x10-6 which is one part in one million or 1 micron in 1 metre. This is increased ten fold to 1x10-7 to determine that the level of accuracy falls under the realm of Ultra Precision Engineering.


These definitions in them selves do not mean very much though. These rather broad definitions really just apply to plain dimensional measurements such as the length of a component. These can still be perfectly valid in a precision engineering process, however they are seldom the only categorisation or precision engineering.


More specific definitions of precision that consider aspect ratio or form accuracy are often more useful and valid as a means of stating that something is precision engineered. For example, there are many small so called precision engineering machine shops that do not use temperature control and struggle to achieve tolerances of even a few microns over 100mm or less. This would not be considered precision engineering. Then there are more modern examples such as micro-machining which also can't achieve the 1x10-6 definition of precision but are accepted as precision engineered components due to their very small size and physical challenges of producing a certain aspect ratio.