Air Jet Assisted Machining of Inconel 718 with Whisker Reinforced Ceramic Tool

Abstract

Nickel alloy is widely applied to aero-engines, marine structures, chemical plants, etc. This alloy has superior mechanical and chemical properties, but is one of difficult-to-machine materials because of its superior properties. For this reason, various machining methods, such as cryogenic machining, hot machining, machining using high pressure coolant and rotary machining have been studied for increasing the cutting speed and cutting efficiency of this alloy. Recently, a new lubrication method called air jet assisted (AJA) machining was developed to extend tool life by 20-30% in finish-turning of Inconel 718 and Ti-6Al-4V. In this machining method air jet as well as coolant was applied to the cutting area. In this study, AJA machining was applied to high speed machining of Inconel 718 with a SiC whisker reinforced ceramic tool. The air jet was applied from an air nozzle at the tool flank face. Because the ceramic tool is likely to suffer from severe notch wear, the influence of AJA machining on flank and notch wear of the ceramic tool was investigated experimentally. As a result, it was found that as compared to conventional wet machining, AJA machining increased flank wear but reduced notch wear, which is usually critical to the tool life of the reinforced ceramic tool. The tool wear characteristics peculiar to AJA machining were effective for extending tool life in high speed machining of this alloy.