EXPERIMENTAL INVESTIGATIONS INTO ULTRASONIC ASSISTED GRINDING OF DIFFICULT TO CUT MATERIALS WITH ULTRASONICALLY ATOMIZED GREEN SOLVENTS

Abstract

Nickel-base superalloys are essential materials for manufacturing niche products like aircraft engines, gas, and steam turbine components. About 50% of aircraft engine components are fabricated from these materials because they have excellent mechanical properties in high temperatures. Due to their physical properties, such as strength and toughness at elevated temperatures, poor thermal conductivity, and high sensitivity to thermal damages, nickel-base superalloys are characterized as materials with extremely low grindability. As a result, several challenges are encountered during conventional mode of grinding in the form of environmental factors, worker health issues, surface integrity, material stability and incessant energy consumption during machining process. Besides this, the emissions from cutting fluids and their disposal are also a concern for the environment. In order to alleviate these problems associated with Conventional Grinding (CG), the present research attempt focused on modifying the mechanism of the grinding process by harnessing the dual advantages of Ultrasonic Assisted Grinding (UAG) and ultrasonically atomized novel green cutting fluid to achieve better performance and enhanced sustainability. In this regard, novel green Ionic Liquid (ILs) based cutting fluids have been developed to address machining processes' sustainability issues. ILs based cutting fluid resulted in enhanced thermophysical and tribological properties as compared to neat rice bran oil. Also, the prepared fluids are free from toxic materials, making them suitable for workers in the machining industries. ILs with Rice Bran Oil (RBO) can be used to mitigate excessive utilization of cutting fluids and emissions of various harmful gases that lead to a negative impact on the environment. Further, the LCA of prepared cutting fluids showed that they have a negligible adverse effect on the environment and are far superior to conventional lubricants. The investigations of cutting forces, Coefficient of Friction (CoF), surface integrity, and chip morphology have been done for different grinding approaches of Nimonic 80A. Then, based on the acquired data, a comparative study has been carried out to investigate the effect of ultrasonic vibration and atomized cutting fluid on the CG operation. A significant reduction in grinding forces by 66.22% and 52.66% for normal and tangential cutting force, respectively, and surface roughness by 46.48% has been observed during Ultrasonic Assisted Grinding with Ultrasonically Atomized Fluid (UaFUAG) as compared to the CG.