A low-cost optical inspection system for rapid surface roughness measurements of CrCN hard films

Chromium carbon nitride (CrCN) hard films own high hardness, lower friction coefficient, higher wear and corrosion resistance. Investigations on the surface roughness of CrCN hard films become an important issue because the surface roughness of CrCN hard films is widely believed to be related to its characteristics of wear and corrosion resistances. A low-cost optical inspection system for rapid surface roughness measurements of CrCN hard films is developed in this study. The incident angle of 20° is found to be a good candidate for predicting the surface roughness of CrCN hard films. Surface roughness, y, of CrCN hard films can be determined rapidly from the average value of the reflected direct current voltage, x, recorded by the optical system developed using the trend equation of y = −18.132x + 185.27. The maximum measurement error rate of the optical measurement system developed is less than 10.37%. The savings in measurement time of the surface roughness of CrCN hard films is up to 83%.