Optimasi dan Analisis Parameter Pemesinan CNC Milling Terhadap Kekasaran Permukaan Aluminium 7075 pada Kondisi Wet Machining

Abstract

Surface roughness is an important indicator of machining quality, particularly for Aluminum 7075, which is widely used in precision industries such as aerospace. Surface quality that meets standards is require to support the coating process in order to achieve optimal adhesion and durability. Roughness values are influenced by CNC milling parameters, especially spindle speed, feed rate, depth of cut, and the use of cutting fluid. This study aims to analyze the effect of variations in these parameters on the surface roughness of Aluminum 7075 under wet machining conditions and to determine the optimal parameter combination for surface roughness used in coating processes. The method employed is Design of Experiment (DoE) with a three-factor, three-level full factorial design, analyzed using ANOVA, linear regression, and a response optimizer. The results show that surface roughness ranges from 0.13 to 0.425 μm. Statistically, no parameter has a significant effect at the 95% confidence level; however, feed rate is the most dominant factor. Theoretically, increasing feed rate and depth of cut tends to increase roughness due to higher cutting forces, vibration, and tool marks, while higher spindle speeds produce smoother surfaces. Parameter interactions are not significant within the research range. The optimal combination is obtained at a spindle speed of 2000 rpm, feed rate of 0.08 mm/tooth, and depth of cut of 0.40 mm, resulting in a roughness of 0.3106 μm. This study can serve as a reference for determining CNC milling parameters of Aluminum 7075 to achieve optimal surface quality for coating processes.