Milling structural components from aluminum under enormous requirements of productivity and quality from the aerospace perspective is still the subject of extensive research. The assessment strategies of the surface quality are a big challenge for the surface measurement technique, since only a fraction of the manifesting surface topography can be described with the help of two-dimensional measured variables. The aim of this experimental investigation is a description of several influences on the parameter of the surface roughness Ra and to analyze the prediction of these values. As a result, it can be shown that a more in-depth analysis is necessary to describe the surface quality and topography, which goes beyond the simple specification of roughness parameters.