Tribology and Cutting Performance of Esters as a MQL Machining Lubricant

Synthetic esters have recently been used as a high performance lubricant in minimal quantity lubrication (MQL) machining. However, there is little understanding about the relationship between the cutting performance and the tribological action of these esters. This study therefore investigates the tribological characteristics of some synthetic polyol esters for MQL machining by using a basic friction test. In the results of this friction test, an ester having more ester bonds in one molecule showed the better lubricity and such trend was prominent at higher sliding speed in the range of the test conditions. The study also evaluated the practical cutting performance of these polyol esters by using a turning test. This evaluation presented, particularly at the cutting speed of 50m/min, an ester showing the better lubricity provided the higher cutting performance.