Characterization of grinding wheel grain topography under different robotic grinding conditions using confocal microscope

Abstract

Knowing the grain geometry in grinding wheels is an asset for better understanding the grinding processes. This study investigates the grain protrusion and rake angles of two self-dressing zirconia-alumina grinding wheels in a robotic grinding process. The topography of the wheel is measured using a confocal scanning laser microscope. An optical image of the surface is used to create a mask of the grains with image processing techniques. Grain geometry information is then obtained by applying the mask to the entire surface. A vertex normal technique is used to find the cutting edges facing the cutting direction and only consider those edges in grain rake angle calculations. Surface parameters, including grain density, width, protrusion height, and rake angle, are extracted from the topography. The grinding wheel is characterized in low, medium, and high depths of cut in the range of robot operation. Results indicate that grain density, width, and protrusion height distribution are not affected by the depth of cut. It is also found that in shallow grinding, grain rake angle shifts slightly to higher negative angles; whereas, with a higher depth of cut, sharper edges exist on the wheel surface, which improve process efficiency.