Investigation into the machinability of non-conventional alloys (Inconel 718)

Abstract

Surface roughness and burr formation are the most important parameters during micro machining process to determine the quality of micro parts. In this research the effect of Cutting speed(m/min), chip load (μm/tooth), depth of cut(μm) and different types of tool coating (AlTiN, nACo, TiSiN ) on Burr formation and surface roughness were studied during the micro machining of Inconel 718 using optical profilometer, scanning electron microscope and statistical technique. Experimentation were performed with chip load below cutting-edge radius for 10mm cutting length using a carbide tool of 0.5mm diameter on the CNC milling machine. From the results it was concluded that depth of cut is the main factor effecting burr formation and cutting velocity is the main factor effecting surface roughness. AlTiN was found to be the best tool coating for minimum burr formation and TiSiN was found to be the best tool coating for surface roughness due to comparatively larger cutting-edge radius the burnishing take place which results in lower surface roughness values. Types of burr formed during micro milling of Inconel 718 was mainly influenced by depth of cut, chip load and was not affected by cutting velocity. It was also concluded for this research that machining below minimum chip thickness cause more burr formation than above minimum chip thickness.