| Description |
Cutting fluid costs represent a large and ever rising portion of the machining process. These costs include acquisition, filtration, separation, disposal, and records keeping for regulatory requirements. Furthermore, coolant disposal cost is higher than the initial coolant cost. Because of these issues, an alternative machining with Minimum Quantity Lubricant (MQL) and Minimum Quantity Cutting Fluid (MQCF) has gained traction as a cost saving and environmentally friendly option compared to wet machining. MQL provides coolant cost reductions, while protecting the environment and worker health. It also reduces cutting temperature and cutting forces. Moreover, MQL improves tool life, surface finish, and chip removal from the cutting zone. Theoretically, an MQL system is designed to deliver a precise amount of coolant and lubricant as an aerosol. That is, the droplet diameter is sustained to provide optimum wetting and lubrication properties. This study of the MQL technique investigates fluid droplet formation as a function of pressure, type of fluid, and distance from the surface with consequent effects on cutting forces and chip formation. The MQL nozzle distance and cutting fluid parameters (nozzle spray angle and droplet distribution) are factors that can provide optimum machining performance in terms of cutting forces and chip size. Experiments were conducted with two cutting fluids and three nozzle distances selected from experimental measurement of the wetting areas of droplet distribution. Flow rate and air iv pressure were selected from experimental results of measuring spray angles. The machining process was evaluated under constant cutting speed, feed rate, and depth of cut when machining AISI 1045 steel. Cutting forces were measured using a dynamometer equipped with a data acquisition system. The experimental results obtained show significant reductions in cutting forces and chip size for vegetable oil at 5 cm nozzle distance, 210 ml/hr, and 0.0551 MPa air pressure. The results also show that minimum cutting forces and chip size for CimTech 310 occurred at 10 cm nozzle distance, 300 ml/hr, and 0.0551 MPa air pressure. The findings herein suggest that complex droplet development, varying fluid properties and composition, and different modes of fluid delivery significantly affect cutting fluid effectiveness during machining operations |
