Promoting resource equity through the systematic literature review in analysing cryo-lubrication techniques for sustainable machining processes

The Cryo-lubrication technique was introduced to minimize the environmental impact produced by traditional flood cooling and to promote resource equity in a sustainable manner. The synergetic interaction of cryogenic coolant and minimum quantity lubrication (MQL) produces a hybrid cryo-lubrication effect that significantly reduces the thermal-mechanical damage associated with tool-workpiece interaction. This leads to enhanced machinability and increased dimensional accuracy. To provide more insight into hybrid lubrication effectiveness, this article presents a systematic literature review of cryo-lubrication techniques for machining many difficult-to-cut materials. Two leading databases, Scopus and ScienceDirect, are used to select 82 relevant research articles published during the last six years from 2018 to 2023. The contents incudes, (a) review of cryo-lubrication fundamentals, (b) summary of the characteristics of cryo-lubrication types, (c) in-depth analysis on the effectiveness and challenges of each cryo-lubrication technique in machining processes, and d) suggestions for future perspectives. It is summarized that cryo-lubrication is better than flood, dry, cryogenic, and MQL environments in demonstrating superior heat transfer characteristics, improving chip breakability, reducing cutting force and power consumption, and enhancing surface integrity. However, in some cases, the excessive surface hardening induced by low-temperature coolant may impedes the machining performance and increased the surface roughness, cutting force, and energy consumption, thereby emphasizing potential advancements in this field.