On the possibility of determining the microtopographic characteristics of the auto sheet surface in technological production lines

One of the important parameters for assessing the surface quality of a car sheet are parameters such as and RPc. These parameters describe the average value of the profile ordinate modulus and the average value of the number of peaks per unit length of the profile, but they do not provide complete information about the topographic structure of the rough surface. In this paper, as an alternative, we propose the use of complex parameters of the RMS slope angle of micro faces of a rough surface and – correlation distance of a rough surface profile. RΔq is a complex parameter. It simultaneously takes into account both the altitude and frequency parameters of the surface profile. Its values are more rigidly correlated with the coefficient of dry and viscous friction, with the strength characteristics of thinlayer materials, with the oil absorption capacity of the surface layer. The parameter τe is used for very smooth surfaces. It has a clear physical interpretation as the distance above which the correlation relationship between the surface ordinates is lost. This distinguishes it from the empirical parameter R Pc The paper describes the technique of measuring and τe by reflectometric method by scattered laser radiation indirectrices (SLRI) and software tools for analysing SLRI by comparing experimental and theoretical data. Examples of the use of this methodology and software tools for determining the surface parameter of both coldrolled and galvanised automotive sheet are given. The results of this work can be used for the development and implementation of devices for noncontact measurement of the most important tribological surface characteristic in the technological lines of automotive sheet production.