As a part of the cutting process, a researched aspect continuously is surface quality. Based on and using the results of previous research, the present scientific paper addresses the problem of the machined surfaces roughness. The cutting process approached in this study is the end-milling one, and the workpiece material used to carry out the study is the aluminum alloy used in the aerospace industry. The adopted cutting regime imply to keep the cutting speed at a constant value while the cutting parameters: cutting depth and feed per tooth vary with different values. The experimental research carried out by the authors in a prestigious industrial company is complicated and complies with the specific methodology. The conclusions stand based on the interpretation of the results obtained from the experiments which were carried out based on the active experimental type. The confirmation of the obtained results was performed using the profiles and images of the microscopic analysis of the machined surface.