Application of Central Composite Design for Optimization Machining Parameters When Machine Magnesium AZ31

Magnesium AZ31 are widely used for industrial manufacturing such as manufacturing aircraft components, automotive, biomaterials and sports. The interests of manufacturing industries for machining Magnesium AZ31 are to obtain high accuracy, high precision and high tool life. The purpose of this experiment is to achieve optimum cutting parameter for tool life and quality of surface finish. A mathematical model for tool life can be computed from this experiment. Magnesium alloy AZ31 as work piece material consist of 3 % of aluminium and 1 % of zinc. The parameters used for experimental trials were cutting speed (v) of 22, 32 and 42 m/min, depth of cut (d) of 1, 2, and 3 mm and feed rate (f) of 0.15, 0.20, and 0.25 mm/rev. Minitab software was used to analyze the data obtained. The maximum actual tool life was 96.7 minutes or longer than 9.36 % from the Central Composite Design prediction, which was 85.78 minutes. This maximum value achieved at cutting speed (v) of 42 mm/min, cutting depth (d) of 1 mm, and feed rate (f) of 0.15 mm/rev. Whereas the mathematical modeling for the magnesium AZ31 in the milling process is Y = 34.7 + 7.69v - 0.426f - 61.5d - 0.0688 v*v + 0.000539 f*f + 1.06 v*d + 0.0363 f*d.