A new strategy for measuring the grain height uniformity of a grinding wheel

[Display omitted] •The heights of all grains on a whole brazed grinding wheel were measured.•The measurement doesn’t need three dimensional reconstruction of wheel topography.•The height was measured directly by an optical system with a narrow depth of field.•The grain heights uniformity with different depths and subregions were analyzed.•The height uniformity can reflect grains state or active grains in a full view. The grain height uniformity of a grinding wheel is a critical parameter in the optimization of the grinding process. A new strategy based on an optical system with a narrow depth-of-field microscope was proposed to determine the peak height of each grain for the evaluation of grain height uniformity based on statistical parameters: standard deviation and skewness. A zoom objective lens was used for a two-step measurement strategy. After planning the measurement path, each grain was vertically scanned, and grain heights were directly extracted according to local minimum image entropies. Grain heights of a #35/40 monolayer brazed grinding wheel were measured and evaluated by statistical parameters. The evaluation results of height uniformity are mean: 360.8 μm, standard deviation: 85.8 μm and skewness: −1.93 for all grains on the grinding wheel. Height uniformity at different depths and subregions of the grinding wheel was also analyzed. Experimental results indicate that the proposed method can measure grain heights on a whole surface or large area without the time-consuming reconstruction of wheel topography and can conveniently analyze height uniformity from different aspects.