Surface roughness values (Ra, Rz, etc.) are important in many applications, industries and materials. Roughness values can be measured by contact methods (Stylus instrument, frictional dynamometer, thermal comparator, electrical methods, etc.) or optical methods (optical probes using laser or infrared beams). Modern digital imaging technologies like digital or laser scanning testers can provide 3D dimensional surface morphology of different types of surface coatings. A local engineering industrial partner needed a method to evaluate the consistency and uniformity of different machined finishes and non-stick release coatings which improve release and reduce wear. Surface roughness measurements were used to evaluate the consistency and uniformity of the finish and coating on samples from multiple suppliers. In this paper, a 3D scanning laser microscope was used to perform the variety types of surface roughness measurements to evaluate the uniformity of different layers of coatings on the specimens. Although not critical for this testing, the use of the laser microscope allowed a non-contact method for measuring surface roughness in order to not damage the coating on the material. Cross-sectional views of these same layers were cut and measured using Keyence digital microscope to evaluate the consistency of the finishing surfaces.

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