Development of a surface roughness measurement system using reflected laser beam

The scattered light pattern reflected from a machined surface generally contains much information concerning the surface roughness. This study examines and proposes a surface roughness measurement technique for the on-machine measurement of the roughness of machined surfaces. The technique is based on the measurement of scattered light patterns and the statistical analysis of the light intensity distribution. Scattered light patterns spread out narrowly in a direction vertical to the tiny scratches on the machined surface caused by tools. The deeper the scratch, the more dispersion there is, which indicates a rougher surface. The standard deviation of the scattered light pattern is nearly in proportion to the surface roughness. Measurements obtained using this method are within 10% of those obtained using a common contact method. Therefore, the proposed method is thought to be effective for use when a quick measurement is needed when a workpiece is fixed onto the machine. (C) 2002 Published by Elsevier Science B.V.