Surface roughness characterization of cast components using 3D optical methods.

A novel method that applies a non-contact technique using a 3D optical system to measure the roughness of selected standard surface roughness comparators used in the foundry industry is presented. This method is described in detail in the paper. Profile and area analyses were performed using scanning probe image processor (SPIP) software and the results of the surface roughness parameters obtained were subjected to statistical analyses. The bearing area ratio was introduced and applied to the surface roughness analysis. From the results, the surface quality of the standard comparators is successfully characterised and it was established that the areal parameters are more informative for sand cast components. The roughness values of the standard visual comparators can serve as a control for the cast components and for order specifications in the foundry industry. A series of iron castings were made in green sand moulds 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. The experiments also show that it is possible to measure the effect of pressure heights on the casting surface roughness.