Thin Wall Milling at a Maximized Axial Depth of Cut: An Analysis of Thermal and Mechanical Interactions

This paper reports the results of a study examining the effect of thermomechanical interactions that occur during a milling process conducted at a maximum axial depth of cut for a thin wall made of aluminium alloy 7050 T7451. The impact of cutting speed and wall thickness on cutting force and cutting temperature was determined. Response surface methodology and face-centred central composite design were used. It was found that raising the cutting speed to approximately v_c ≈ 700 m/min led to an increase in cutting force component F_x and cutting temperature T, followed by a decrease in their values. Nonetheless, these variables at v_c = 900 m/min were considerably higher than those observed at v_c = 300 m/min. The thinnest tested wall of t = 1 mm exhibited the greatest process instability and evident signs of chatter, while a wall thickness increase to t = 2 mm resulted in improved process stability and reduced flatness deviation. The interaction between the cutting force and the cutting temperature, as well as the occurrence of chatter, were established as two dominant factors affecting thin wall machining accuracy. Results showed that the assumed empirical models could be used to predict the tested dependent variables under similar milling conditions.