Surface finish scatters the light

Previous studies have shown that majority of engineering component failures start at the surface of a manufactured artefact. This observation indicate the significance of surface finish and roughness of manufactured surfaces. For the past years and up to the present, industry spends much time and money inspecting machined surfaces. The traditional method of inspecting such surfaces is by contact profilometry, a stylus-based technique. This technique however suffers from several problems with respect to production line compatibility. In view of this, the use of light-scattering techniques has been considered as an attractive alternative to profilometry since they can be easily employed online.