Measurement of surface roughness of coated wood by laser scanning

We discuss the effect of surface glossiness of the coated wood on the evaluation of surface roughness using the laser scanning. Wood specimen, Japanese beech (Fagus crenata Blume), were sanded using coated abrasives of from P80 to P400 grit, and one series of them were coated by poly-urethane and the other not coated. Surface profiles were measured by the stylus instrument and the laser scanning, and the results from both instruments were compared each other at each grit. In addition to the glossiness, the effect of the difference of grit was discussed.

Sanded surface Figures 1 shows the primary profiles from sanded surfaces. It is obvious that there is no significant difference between the measuring methods, and the amplitude of profiles is smaller for fine abrasives than that for coarse one.
Laser Stylus
Painted surface Figures 2 shows the primary profiles from the coated surfaces. Compared with the sanded surface, higher frequency components of quite a large amplitude are superposed on the primary profiles for the laser method, and the difference in profiles between the grit sizes of coated abrasives is unclear.
Laser Stylus

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