A non-contact 3D method to characterize the surface roughness of castings

A non-contact technique using a 3D optical system was used to measure the surface roughness of two selected standard surface roughness comparators used in the foundry industry. Profile and areal analyses were performed using scanning probe image processor (SPIP) software. The results show that the surface quality of the standard comparators was successfully evaluated and it was established that the areal parameters are the most informative for cast components. The results from the surface comparators were compared with the results from a stylus instrument. Sand cast components were also evaluated and the surface roughness parameter (Sa) values were compared with those of the standards. Sa parameter suffices for the evaluation of casting surface texture. The S series comparators showed a better description of the surface of castings after shot blasting than the A series.

► Surface roughness of cast components surface and comparators were successfully evaluated.
► Metallic surface comparators describe casting surfaces better than the polymer types.
► Areal measurements are more informative and representative than profile measurements.
► Areal measurements take less time than the profile ones.
► Higher magnifications (5×) do not give real surface evaluation of sand cast surfaces.