Experimental study of surface roughness and geometrical and dimensional tolerances in helical milling of AISI 4340 alloy steel

摘要

The ability to manufacture a product is assessed by factors such as surface quality and features tolerances. The main goal of the present investigation is to carry out an experimental study on the accuracy of holes produced through a novel helical milling process on AISI 4340 alloy steel. This process is referred to as production of holes through mobile milling on a helical path. Taguchi experimental design method was used in order to investigate the effect of the main parameters including feed rate, cutting speed, axial depth of cut, and workpiece hardness on the hole surface roughness and geometrical and dimensional tolerances. In addition, the impact of using two methods of minimum quantity lubrication and dry milling was discussed. The results showed that the helical milling method can be a suitable alternative for conventional drilling. Lubrication method was the most effective parameter on surface roughness and nominal diameter with contribution of 43 and 41%, respectively. In addition, cutting speed had the most impact on circularity and cylindricity with contribution of 44 and 41%, respectively. Furthermore, the most precise hole was obtained at cutting speed of 70 m/min and feed rate of 0.01 mm/tooth in presence of minimum quantity lubrication system using vegetable oil, while using mineral oil led to making a hole with highest surface quality.