Étude expérimentale des effets de l'outil de coupe, des conditions d'usinage et de lubrification sur la qualité de surface et le comportement en traction des pièces en alliages d'alluminium

Abstract

In the aircraft and aerospace industry, a particular attention has been given to the performance in service and reliability of parts. This performance is linked to the used shaping processes, and especially to the surface integrity of the produced parts. The aim of this work is to study and optimize the machining parameters to ensure a better surface quality of the parts. Specimens made from aluminium alloys (AA2024-T4, AA6061-T6 and AA7075-T651) were machined in turning Under different cutting conditions (feed rate and nose radius of the tool) and under various lubrication modes (dry, semi-dry and flood lubrication) to determine the effects of the cutting conditions on parts quality and their tensile behavior. Following a statistical study based on the design of experiments methodology, it was found that the feed rate and the nose radius of the tool are the most significant factors affecting the surface roughness, the residual stresses and the tensile behavior for the three materials studied. Machining with the minimum quantity of lubrication stood out with the best results for all investigated responses. It was observed that the surface roughness increases with the decrease of the nose radius of the tool and the increase of the feed rate. Residual stresses with compressive tendency were observed for the lowest feed rates and for the smallest nose radiuses of the tool. The tensile behavior was found to be more dependent on the workpiece material than on the machining conditions. Predictive empirical models for the surface roughness, the residual stresses, the yield strengths, the ultimate tensile strengths and the breaking strengths have been suggested. An optimization of the cutting parameters and the lubrication modes has been proposed to ensure a better surface quality and, subsequently, a better performance in service of the parts.

Date	23 Apr 2015
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Victor Songmene (Supervisor), Mohammad Jahazi (Co-supervisor) & Jules Kouam (Co-supervisor)