Proposal of a Computational Algorithm for Calculating Material Ratio of Surface Texture

Surface textures are geometric features that collectively refer to surface roughness and scratches. The surface textures are highly relevant to the geometric specifications such as mechanical properties and appearance of the product. Therefore, the quantitative quality control of the surface texture is necessary. The surface textures are important for bearings are used in automobiles and other products. The material ratio curve of the surface texture is used as an effective evaluation method for the quality control of bearings and other products. The material ratio curve shows the ratio of the material part and the void part of the surface profile in the height direction. The computational algorithms to obtain the material ratio curve have been proposed by the ISO/JIS standard and previous research. The computational algorithm proposed in ISO 13565-2 for calculating material ratio curve is a method of slicing the roughness profile (hereafter referred to as “slice method”). The slice method has problems that the calculating time increases as the slicing number increases. Therefore, in this study, the sort method is proposed as a computational algorithm for time reduction. The sort method is a method to sort data in ascending order. As a result, the sort method was successful in reducing the calculating time on the material ratio curve. However, depending on the form of the surface profile, the computational algorithm of the proposed sort method has a problem that calculation errors occur. Therefore, in this paper, we report a new improved algorithm that solves this problem. This algorithm can contribute to improve the efficiency of quality control through rational analysis and evaluation.