Surface measurement—synonymous with surface metrology—determines surface topography, which is essential for confirming a surface’s suitability for its function. Surface measurement conceptually includes surface shape, surface finish, surface profile roughness (Ra), or in surface area roughness (Sa), surface texture, asperity and structural characterization.
For example, engine parts may be exposed to lubricants to prevent potential wear, and these surfaces require precise engineering— at a microscopic level— to ensure that the surface roughness holds enough of the lubricants between the parts under compression, while it is smooth enough not to make metal to metal contact. For manufacturing and design purposes, measurement is critical to ensure that the finished material meets the design specification.
Image to the left is of a Intaglio printed paper bank note