Recent developments in MQL machining of aeronautical materials: A comparative review

Abstract

Minimum quantity lubrication (MQL), as a new sustainable and eco-friendly alternative cooling/lubrication technology that addresses the limitations of dry and wet machining, utilizes a small amount of lubricant or coolant to reduce friction, tool wear, and heat during cutting processes. MQL technique has witnessed significant developments in recent years, such as combining MQL with other sustainable techniques to achieve optimum results, using biodegradable lubricants, and innovations in nozzle designs and delivery methods. This review presents an in-depth analysis of machining characteristics (e.g., cutting forces, temperature, tool wear, chip morphology and surface integrity, etc.) and sustainability characteristics (e.g., energy consumption, carbon emissions, processing time, machining cost, etc.) of conventional MQL and hybrid MQL techniques like cryogenic MQL, Ranque-Hilsch vortex tube MQL, nanofluids MQL, hybrid nanofluid MQL and ultrasonic vibration assisted MQL in machining of aeronautical materials. Subsequently, the latest research and developments are analyzed and summarized in the field of MQL, and provide a detailed comparison between each technique, considering advantages, challenges, and limitations in practical implementation. In addition, this review serves as a valuable source for researchers and engineers to optimize machining processes while minimizing environmental impact and operational costs. Ultimately, the potential future aspects of MQL for research and industrial execution are discussed.