Influence of Reverse Finishing on Characteristics of Drilling Surface

Aluminum alloys are often used in automobile and aircraft parts that require higher dimensional accuracy and durability. Drilling is often used in the machining process of these products and accounts for about 60% of the machining performed on these products. Deterioration of finishing surface accuracy in drilling causes problems such as decreased tool life due to wear and increased cost due to the introduction of the finishing process. The objective of this study is to evaluate the finished surface characteristics in the drilling of aluminum alloys using reverse finishing, with a focus on the cutting direction of finishing, with respect to the roughing direction. The torque and thrust force are smaller in reverse finishing than in forward finishing. The reduction effects of cutting force in reverse finishing were more significant when the finishing depth of cut was smaller in relation to the roughing-affected layer. Under conditions where the finishing depth was equal to or greater than the roughing-affected layer, it was possible to reduce cutting forces and improve surface roughness while obtaining compressive residual stresses equivalent to forward finishing.