The surface quality study of the cutting processes is a very current and complex subject, which approached in variously specialized researches. This paper is a continuation of our previous research. The primary objective of this paper is to track the evolution of the surface roughness measured longitudinally on the feed motion direction in the end-milling process of an aluminum alloy used in the aerospace industry. The active experiment is the research method used to achieve the proposed objective. The cutting regime adapted to carrying out the necessary experiments supposes a constant cutting speed, while the cutting depth varies with different values. Obtaining the experimental data did possibly using the roughness tester as a measuring device. The obtained measurements were used to determine the surface quality evolution in the various situations of the cutting regimes resulting from the combination of the process parameters considered in the analysis. The experimental study is very complex and carried in an industrial organization that focuses on the aerospace industry. Through this original research that was carried out in the smallest details, a series of comparative graphs of the surface roughness evolution performed under the cutting depth variation, which led to a package of conclusions to have taken into consideration.