The Size Effect in Metal Cutting

A cutting process involving the formation of very small chips at high cutting speeds (micromilling) is investigated, and the results are applied to a study of the grinding operation. The shear energy involved in grinding is compared with that in turning, micromilling, and the tensile test, and a significant increase in shear energy is observed with decrease in specimen (chip) size. The shear stress involved in grinding metals under mild conditions is found to correspond to the theoretical strength which is about 1.8 × 10⁶ psi for steel. The grit depth of cut is shown to be a more important variable in the interpretation of grinding data than the more conventional wheel depth of cut.