Investigation of Burr formation and Surface roughness in Micro milling of Inconel 718 alloy

Abstract

Industry, particularly aviation, has seen remarkable technological advancement in recent years. More micro-scale manufacturing capabilities, notably micro-milling capabilities, are required for high precision machined microparts with complex features in order to obtain the necessary yet exact dimensional accuracy and surface finish. In this study, the influence of feed rate, cutting velocity, depth of cut, and four various types of tools with (AlTiN-, TiSiN-, nACo-coatings, and uncoated) on burr formation, tool wear and surface roughness during micromachining of Inconel 718 was investigated using digital microscope and statistical techniques. On a CNC milling machine, machining experiments were carried out at high speed with a feed rate below the cuttingedge radius for a 10 mm cutting length with a carbide tool of 0.5 mm diameter. The depth of cut was shown to be the most important element in burr creation, whereas cutting velocity was found to be the most important component in surface roughness. Due to the difference in coefficient of friction, cutting tool coating had no effect on either surface roughness or burr development. The depth of cut and feed rate influenced the kinds of burr generated during micro-milling of Inconel 718 while cutting velocity had no effect. It was also determined that the surface finish achieved by high-speed machining is equal to that achieved by transition and low-speed machining and that the burr width discovered during high-speed machining confirmation trials was likewise within an acceptable range.