Abstract. In recent years, minimum quantity lubrication (MQL) machining is regarded as a promising method for reducing machining cost and cutting fluid, while improving cutting performance. However the effectiveness and the working principle of MQL are still questionable with very few explanations provided. The aim of this study is to determine the optimum distance between the nozzle and tool tip and appropriate flow pattern of the mist flow for minimum quantity lubricant using Particle Image Velocimetry (PIV) and Computer Fluid Dynamic (CFD) for optimizing the spraying conditions thus reducing the lubricant consumption. The spray from the nozzle with outlet diameter of 2.5 mm is analysed using Particle Image Velocimetry (PIV) to measure the mist flow velocity and identify the flow pattern. The input pressure of 0.2, 0.3 and 0.4 MPa will be discharged throughout the experiment. Higher pressure produce more mass flow rate which helps in reducing the cutting force and cutting temperature efficiently and prolong tool life. Thus the appropriate distance can reduce lubricant consumption and increase the cooling and lubricating ability with best nozzle position. The applied distance increases the efficiencies of MQL applied during machining process.
IntroductionDue to serious concern about ecological and economical and most importantly occupational pressure, many machining industry are turning towards dry machining to eliminate the usage of metal working fluids. Multitude researches have been conducted to replace wet machining.[1] Wet machining are not highly desirable due to its affects that causes respiration and skin problems to the workers who are highly exposed during machining process.[2] Meanwhile, in dry machining metal working fluids are not used thus leaving a dry and easy to clean workplace. Despite the advantages of the dry machining, there are some limitations in dry machining that leads to the usage of metal working fluids. Dry machining can be less effective when higher machining efficiency, better surface finish quality and severer cutting conditions are required. By taking into consideration of the ecological and economical problems, implementing near dry machining or minimal quantity lubrication (MQL) would be the best technique to control or to reduce the metal working fluid consumption. Based on studies done using MQL technique have shown reduction in friction coefficient and cutting temperature compare with dry and wet machining. [3] In MQL cutting, a small amount of biodegradable oil, which is mixed with compressed air to form oil mist, generated using a process called atomization is applied to the cutting point instead of the flood supply of water-miscible or water-immiscible cutting fluids to lubricate, reduce temperature and to enhance the tool life during the machining process [4]. For example, it was assumed that the oil can penetrate the tool-workpiece interface due to high pressure of the compressed air that serves as a vehicle for the oil droplets [5,6]. No comparison was made between the...