Integration of an optical roughness sensor with a co-ordinate measuring machine

An optical roughness sensor is described that is ideally suited for integration with a co-ordinate measuring machine (CMM). The CMM provides an extremely stable platform for moving the sensor head over the surface specimen. The sensor consists of a fibre optic head, data processing electronics and software for controlling the sensor and calculating surface texture parameters from the sensor's data. The software controls the data acquisition process, filters the data to remove sensor noise and calculates basic amplitude parameters that describe the texture profile of the surface. Tests have been conducted on surfaces and the results compared with stylus profilometer measurements on the same surface regions. Comparison of the amplitude parameter, Ra, shows differences of between 3 percent and 8 percent across the sample set for profiles in the 0.4 μm Ra range.