The profile physical coefficient and its application for modelling the machined surface texture

Current trends in the development of mechanical engineering impose increasingly stringent requirements for the performance characteristics of manufactured goods. The main parameters characterizing the quality of a product as a whole are the physical, mechanical, and geometric indicators of the working surfaces of the compound units. In domestic practice, a machined surface is mainly characterized by a rather limited number of parameters (no more than 6), such as the average microroughness height, the microroughness height at 10 points, etc. However, their use is not enough to manufacture competitive products in the modern conditions. For example, international ISO/ASME/DIN standards include a much broader set of parameters required to accurately describe the performance properties of a surface. The paper analyzes the approaches to the formation of requirements for the microgeometry of the working surfaces of parts used in modern mechanical engineering. Based on the analysis, the author proposed and mathematically substantiated a general approach to modelling surface texture characteristics, which allows describing adequately the surface using a new parameter – the profile physical coefficient, since it is virtually impossible to directly compare the technologies developed in Russia with foreign analogues based on the current standards. First, the profile physical coefficient was determined at the section level. Next, it was decomposed into a Fourier series for the two-dimensional and three-dimensional cases. The paper presents the analysis of the new parameter applicability on the example of a product obtained by honing. The author concluded about the applicability of this parameter and the necessity to develop a comprehensive methodology based on it for evaluating the surface after machining.