Sheri K. Kurgin

A characterisation of mist generated from minimum quantity lubrication (MQL) compared to wet machining

Minimum quantity lubrication (MQL) is a new machining method in which an oil mist in a compressed air stream, rather than a flood coolant, is applied to the machining area. Three types of MQL systems exist today: external; internal, single channel; and internal, dual channel. Mist is applied differently with each type of MQL. However, the characteristics of the mist (concentration and particle size) have never been studied. Some studies have stated that MQL results in zero airborne mist levels since the oil mist either vaporises or clings to the workpiece or chips. In this research, we monitored the mist from wet fluid application and from each type of MQL system and we considered the pros and cons of each MQL type.

Evaluation of the convective heat transfer coefficient for minimum quantity lubrication (MQL)

Purpose – The purpose of this paper is to evaluate the cooling ability of minimum quantity lubrication (MQL) cutting fluid.Design/methodology/approach – An experimental system is devised to find the heat transfer coefficient of MQL under simulated reaming conditions. Cooling rate of the specimen is measured with an infrared camera. The effect of air pressure and oil volume on cooling rate is tested. Metal cutting tests are performed to evaluate the effect of heat transfer coefficient on workpiece temperature.Findings – Convective heat transfer coefficient for MQL increases with increasing air pressure. Oil volume has an indeterminate effect on the heat transfer coefficient; however, it is a dominant factor for controlling temperature during reaming.Practical implications – The results of the study can provide guidance to optimize the temperature controlling ability of MQL for production.Originality/value – There is limited information available in literature regarding the heat transfer coefficient of meta...

A comparison of two minimum quantity lubrication delivery systems

Purpose – The purpose of this paper is to compare the performance of single- and dual-channel minimum quantity lubrication (MQL) for reaming spool bores in an automotive transmission valve body. Design/methodology/approach – Machining experiments are conducted under various parameters for both single- and dual-channel MQL. Comparison metrics include part surface temperature, spindle power consumption and hole quality. Experimental data from traditional through-tool flood coolant are provided as a baseline for spindle power consumption and part quality. Findings – The results show that with proper tooling and machining parameters, dual-channel MQL can perform equivalently or better than flood coolant. Single-channel MQL was not deemed suitable for this machining application. Practical implications – The results of the study show that MQL can be successfully applied for precision reaming of aluminum and can provide guidance in developing an MQL system. Originality/value – Few studies have been performed for...

Cutting insert and work piece materials for minimum quantity lubrication

There is considerable interest in utilizing either dry or minimum quantity lubrication (MQL) as an alternative to flood cooling due to environmental concerns with flood coolant such as excessive misting and disposal of the used coolant. Dry machining can result in high tool wear and also built up edge problems on the cutting tool. The objective of this research was to study the effect of work piece material and tool material on the machining characteristics, in this case reaming, of aluminum using MQL. In particular, a high tin casting and three different tool materials: carbide, DLC and PCD were studied. The high tin casting was found to produce lower cutting temperature and lower spindle power. The PCD coated insert performed the best in terms of lowest temperature rise, lowest spindle power and highest part quality.