Study on a Computational Algorithm for Material Ratio of Surface Texture

Abstract

Surface textures are significantly related to the geometric specifications of products, and thus, quantitative quality control is required. The material ratio curve (MRC) and MRC parameters, which are methods for evaluating surface textures, are effective methods for evaluating surfaces with excellent lubrication and frictional characteristics. MRC is a curve that shows the ratio of the material and void parts of the surface roughness to the height direction, represented by the height of the surface profile on the vertical axis and the percentage of the material part on the horizontal axis. MRC proposed in ISO 13565-2, ISO 21920-2 and ISO 4287 has long been known and applied in the automotive industry and other industries. MRC and MRC parameters are widely used as effective evaluation methods for the quality control of automotive parts and bearings in the industry. The algorithm for calculating MRC proposed in the ISO standard has the problem that it requires more computing time as the number of slices against the roughness profile increases. In recent years, surface roughness evaluation has increased the demand for the areal surface texture measurements, and the measurement data of the areal surface texture has surface roughness profiles of at least 50 to 300 lines in the depth direction. Therefore, the ISO 13565-2 standard method does not satisfy the realistic time at the production site due to the time required to calculate MRC. Hence, in this study, we propose the sort method as an algorithm for calculating MRC, in which the computing time is reduced. However, it was found that this calculation method had some problems depending on the shape of the profile of the measurement data. Therefore, in this paper, we report a new improved algorithm that improves this problem. In this study, an algorithm for calculating MRC using the sorting algorithm has been researched and developed. The proposed algorithm in this study succeeded in reducing the computing time to derive MRC compared with the calculating algorithm of MRC proposed in the ISO standard. Therefore, we consider that computational algorithms can contribute to the efficiency of quality control in the industry.