Laser diffraction method of surface roughness measurement

Traditional contact probe and stylus methods have been difficult to apply for the measurement of the roughness of sculptured surfaces, especially whose positioned at under high inclination. The laser diffraction method is presented as a method for remote surface roughness measurement that can be used directly on a machine tool or a press for any position of complex sculptured surfaces. This method can be used to measure the surface roughness of various materials, both metals and non-metals, as well as hard ceramic and soft plastic such as for rapid prototyping. The main technical difference of the method suggested is the use of a new optical system and the automatic determination of the luminous radiation reflection coefficient by a proposed analytical dependence. Specifically, the method involves the simultaneous measurement of the mirror reflected radiation beams as well as the scattered spectrum component and then the numerical processing of reflected laser light signal by developed software. The measurement results taken for different machining processes of complex sculptured surfaces have shown a good correlation with the results of stylus methods.