Abstract
This study focuses on the quality of ground surface cooled by supersonic air spouted out of Convergent-Divergent (C-D) nozzle on cool-air grinding, fluid free grinding. The negative effects of cutting fluid upon people and the environment have recently become a serious problem so the C-D nozzle has just developed for reduction of the coolant. Supersonic cool air from the C-D nozzle is supposed to prevent the ground surface from rising temperature and to maintain the surface quality. Temperature of the air at the inlet of the C-D nozzle was selected to be from −55°C to 20°C to verify an effect of the supply temperature of the air on the surface quality. A test material, alloy steel SCM435H, was ground for a comparison of cool-air grinding using C-D nozzle with both of the conventional wet grinding, which uses grinding fluid, and the dry grinding. It appears that the cool-air grinding using C-D nozzle is found to perform well from a viewpoint of the surface quality. The result of the experiment shows that the cool air is capable of decreasing the tensile residual stress. Supplying the supersonic cool air (T0<−45°C) to the grinding point turns the residual stress compressive since the supersonic cool air sufficiently decreases the grinding temperature. This study provides the cool-air grinding can produce good ground surface quality.
