A Controlled Atmosphere Cutting Apparatus for Understanding Tribological Behavior of Lubricants in Near-Dry Machining

Minimal Quantity Lubrication (MQL) cutting is a successful example of near-dry machining operations. Using actual milling operations, this study shows that equivalent or sometimes superior cutting performance of MQL cutting with a biodegradable synthetic ester lubricant can be achieved in comparison with the conventional cutting with flood coolant supply. There is little investigation on reasons for the preferable performance, such as increase in tool life and the improvement in surface finish. With an extremely low quantity of a lubricant, this study also aims at understanding fundamentally the tribological behavior of a small amount of lubricants during metal cutting. For this purpose, a controlled atmosphere cutting apparatus is developed. The apparatus can introduce a small amount of lubricants in vapor phase into the cutting chamber and can measure their adsorption characteristics by a mass spectrometer. Based on the results obtained by this apparatus, the tribological behavior of a model ester is discussed in connection with the effectiveness of the synthetic ester, which is a suitable lubricant for MQL cutting. Furthermore, the modified version of the apparatus equipped with a cutting force dynamometer is proposed to evaluate the cutting performance in a controlled atmosphere.