29 February 2018 INDUSTRIAL ENGINEERING JOURNAL Vol. XI & Issue No. 2 February - 2018 RECENT TRENDS IN THE EFFECTIVE UTILIZATION OF MINIMUM QUANTITY LUBRICATION (MQL) IN TURNING LOW CARBON STEELS Miriyala Veera BhadraRao Dr. Vasim A. Shaikh Dr. Bhushan T. Patil Abstract Researchers have identified machining as the most versatile manufacturing process as compared to metal forming process due to its ability to get close dimensional control, better surface finish and higher production rate. Minimum Quantity Lubrication (MQL) has been a replacement to conventional flood and dry machining due to optimal coolant usage, good heat dissipation at the cutting zone and ecological safety concerns. C15 steels which are low carbon steels find major applications in production from small pins to large axles and shafts. It has advantage over other materials due to its good strength, low cost, ease of heat treatment and machinability. Many researchers have discussed the economical, environmental and health effects of dry, flood and MQL machining during turning steels. This paper reviews the selection of optimum cutting parameters in turning of steels with dry, flood and MQL cooling with or without nano-material. Critical responses analyzed by some researchers during these studies were tool life, surface roughness, material removal rate, energy utilization, cutting forces and tool-work-piece interface temperature, effects of mist generated during machining, chip morphology, mist concentration analysis and improper disposal of cutting fluids. This paper also reviews tool-work interface temperature and cutting force measurement by computational fluid dynamics (CFD) techniques and finite element analysis (FEA) respectively. Finally, an overview of optimization tools such as response surface methodology (RSM), particle swarm optimization (PSO), Design of Experiments and Taguchi method are put forth to establish proper inter-relationship of factors, levels and responses to solve problems in machining especially, mist pollution, surface improvements and tool life enhancement. Keywords – Minimum Quantity Lubrication(MQL), Nano-Material, Optimization, Steels, Turning INTRODUCTION Metal machining processes such as turning, milling and drilling are very versatile and economical. These machining processes give shape to work-piece by removing the materials by the action of shear from the work piece surface using a hardened sharp edged tool and also establishes a relative motion between the workpiece and the cutting tool. The metal machining (i.e. chip forming) process is preferred over metal forming process due to its ability to achieve high precision in workpiece tolerances of up to 50 microns and a workpiece surface finish of up to 1 microns. The metal machining process is considered versatile to other manufacturing processes due to the fact that the machines are flexible to part-program for different free- form shapes, different size ranges and can be automated. Moreover, machining process requires least use of dies or moulds as compared to metal forming processes. Also, with the advancement of newer tool coating materials, better machinability, reduction of lead time and fast delivery of manufactured parts are at par with industry requirements in today's demanding customer-driven environment [1]. As far as machining operations are concerned, steel (eg. free machining steel – C15 steel) is majorly been a work material due to the large availability of iron ore deposits in the earth's crust. It has excellent mechanical properties such as strength, toughness and good machinability and it is easy to fabricate into different shapes. C15 steels find its applications majorly in the manufacture of large quantities of screwed components, shafts and different components of automobiles. Among the different machining operations, turning operation has been successful since 1960's for carrying out several operations on cylindrical objects with accuracy and speed. In this process, various experiments were conducted by researchers on improving the machining quality of work and improvement of cutting tools. It was found that major issues existed with this process especially in the area of health and safety of the workers and environmental impacts. Different research works have proved that machining using flood cooling is injurious to health and used coolant if not treated properly and disposed off in sewage harms the environment biotic things to a large scale. Avoiding flood cooling altogether (i.e. dry machining) also has many disadvantages, in terms of low tool life and bad surface quality of work. In this case, the use of cutting fluid which is inevitable and prime need for any machining has led to minimal use of coolant technology in machining called as “Minimum Quantity Lubrication – MQL” or also called as “Near – Dry Lubrication – NDL”. This technology has been advantageous to the machining sector due to the fact that chips after machining are almost dry and need no further drying and can be recycled again at economy. Lubricant in MQL system is forced into the cutting zone with compressed air up to 5 bar pressure with lubricant concentration of 0.2 to 500 ml/hr. The lubricant molecules evaporate quickly after leaving the machining zone leaving nothing to recycle back to the MQL system. This avoids disposal problems to a large extent. It is found by researchers that MQL system produces very less mist (aerosol) in atmosphere 3 (permissible exposure level –PEL) of up to 5 mg/m and 0.5 3 mg/m which are within the standards of air quality prescribed by OSHA (U.S.- Occupational Safety and Health Administration) and NIOSH (U.S.- National Institute for Occupational Safety and Health). Compared to this, flood DOI: 10.26488/IEJ.6.10.5 DOI: 10.26488/IEJ.6.10.5 DOI: 10.26488/IEJ.6.10.5 ISSN:2581-4915 ISSN:2581-4915 ISSN:2581-4915