A MAGNETORHEOLOGICAL POLISHINING BASED APPROACH FOR STUDYING MAGNETIC/NONMAGNETIC WC HARD METALS

摘要

We have demonstrated that a MRF spot can be place on ground surfaces of tungsten carbides and that the spot can be used to evaluate the depth of the surface deformed layer, also known as SSD. We found that for the rough and medium tools, SSD depth is in the range 1.5-2.7 urn. The surface roughness of the MRF spot at the deepest point of penetration (ddp) can be used as a guide for establishing the optimal amount of material to be removed by subsequent grinding or polishing steps. By utilizing both surface-roughness measurements and SEM imaging at the spot ddp, we were able to estimate the depth of the deformed layer. Thus, we showed that the depth of the deformed layer can be estimated in two ways. An optical profilometer-based measurement of the p-v surface microroughness of the ground surface provides an upper bound to the deformed layer thickness. This is a desirable estimate given the noncontact nature of this metrology technique. On the other hand, the MRF spot can also be used to reveal the true depth of the deformed layer while reducing the surface-roughness.