Study on Affect by Calculation Algorithm for Material Probability Curve to Roughness Parameters of Plateau Surface

Abstract

The automotive industry requires effective evaluation methods for the quality control of automobile parts and bearings. The ISO standard defines the calculation of roughness parameters from the material ratio curve (“MRC”) and material ratio curve on normal probability paper (“MPC”) as effective methods for evaluating surfaces with excellent lubrication and frictional characteristics. ISO 4287 specifies the slice method as a calculation method for the MRC. The analysis time of the slice method is long due to the large amount of calculation required. Therefore, ISO 21920-2 specifies the use of the sort method. The sort method reduces the analysis time significantly due to the small amount of calculation required. A previous study revealed that errors occur in the MRC using the sort method compared to the slice method. However, the previous study concluded that the errors were acceptable compared to the time cost. In addition, the plateau surface is a surface with excellent sliding properties. The roughness parameters of the plateau surface have to be calculated from the MPC. However, in the case of expression on normal probability paper, the difference between MRCs calculated by the sort and slice methods increases as both ends approach. Therefore, the results of roughness parameters calculated by each MPC are expected to be different. This study reports the results of an investigation into the effect that increasing differences have on the roughness parameters. We aim to contribute to the establishment of a highly effective evaluation method by verifying the validity of using the sort method in the calculation of the MPC.

Keywords

• material ratio curve
• material probability curve
• sort method
• slice method
• ISO 21920-2
• ISO 4287