Automated surface roughness measurement

A non-contact roughness sensor is described that is suited for integration with a computer-controlled coordinate measuring machine (CMM). The sensor e mploys a fibre optic interferometer, electronic control system and data-pro cessing software. The combination of the sensor and computer controlled CMM allows surface texture assessment to be made during scheduled dimensional inspections of complex curved surface components, such as turbine blades. T he sensor system will measure surface roughness parameters, for example R-a , using a method that reflects standard procedures. The lightweight sensor head can be mounted on a touch probe arm and the associated articulated mou nting head; this combination gives quasi 5-axis positioning ability to the overall sensor. This is suitable for automated surface finish inspection of compound curved surface blades. The sensor and its control unit are integr ated with the CMM controller and its operation can be controlled through st andard part-program commands used by the CMM.