Conventional Minimum Quantity Lubrication Research Articles

Experimental investigation on performance of bubble-bursting atomization methods for minimum quantity lubrication in face milling tool steel

The metal cutting industry faces challenges in machining hard materials due to high forces and temperatures. This paper introduces bubble-bursting atomization minimum quantity lubrication (BBA-MQL), a novel MQL technique that generates fine biodegradable oil mists for cooling and lubrication. Although the initial results of BBA-MQL are promising, there has not been a comprehensive investigation into its use in machining hard materials, specifically tool steels. Therefore, this study focused on the applicability of BBA-MQL in face milling of AISI P20 + Ni tool steel in comparison with dry cutting and conventional MQL using commercial and vegetable oil. The machining tests were performed at three cutting speeds (50, 80, and 110 m/min), fixed cutting depth (0.2 mm), and feed rate (0.15 mm/tooth). The performance is evaluated by measuring the cutting force, surface quality, cutting temperature, and tool wear. It was found that BBA-MQL decreased cutting force and surface roughness considerably, with the average reductions being 23.2 % and 49.8 % compared with the conventional minimum quantity lubrication. The highest cutting speed of 110 m/min was preferred for achieving the lowest roughness value and cutting force when milling tool steel P20 + Ni. Furthermore, BBA-MQL with castor oil proved more effective compared to conventional MQL in reducing cutting force, showing improved surface finish, reduced cutting temperature, and delayed tool wear.

Exploratory data analysis & EDS analysis on tool chip adhesion under dry and nano minimum quantity lubrication machining environment

Adhesion, abrasion, plowing and transverse displacement are the major causes of origin of friction. During dry machining of ductile materials, chips are fused with the rake face of the cutting tool and contribute to the formation of the built up edge. Built up edge protects the rake face of the tool from wear, but makes the machined surface rough. To improve the tribological properties and to decrease the tool-chip adhesion, cutting fluids are used. Cutting fluids are added to the machining zone to minimise cutting temperature and friction, but they result in environmental and health degradation. Surface texturing of tools is a potential way to modify the tribological properties of mating surfaces in order to increase the tribological qualities and decrease the tool-chip adhesion. The performance of surface textured tools depends upon orientation, dimple depth, width and pattern. Under lubrication regime, microholes in surface textured tools acts both as lubrication reservoir and traps wear debris to reduce abrasive wear. Nano Minimum Quantity Lubrication (nano-MQL) is an advanced lubrication technique used in machining processes, specifically designed to minimize the use of lubricants while maintaining effective lubrication. This method involves delivering an extremely small amount of high-performance lubricant directly to the cutting zone. The MoS2 lubricant with sunflower oil is typically in the form of nanodroplets, which are much smaller than conventional minimum quantity lubrication (MQL) droplets. The Exploratory Data Analysis (EDA) methodology enables the identification of patterns, trends, and outliers within the collected data, offering insights into the complex interplay of factors affecting the machining of Aluminium Alloy AA2024. At a spindle speed of 3500 rpm the feed force decreases by 37% under dry environment when compared with nano-MQL environment. Under dry environment average surface roughness reduces by 27% when compared with nano-MQL environment.

Experimental investigation of oxygen as carrier gas in minimum quantity lubrication milling of H11 die steel

Minimum quantity lubrication (MQL) is one of the promising green manufacturing technologies to meet the challenges in the dry machining of hardened die steels. The present work aims to show the effects of various machining environments like dry, MQL with compressed air and MQL with oxygen in the milling of H11 die steel. A biodegradable ester LRT 30 (24cSt at 40 °C) was used as a cutting fluid. The results showed that the MQL with an oxygen-enriched environment provided better results in terms of reduction in cutting force, surface roughness and tool wear. It was also found that the MQL with oxygen was more effective when the cutting velocity ranges between 125 and 150 m/min, as compared with conventional MQL with compressed air. The oxygen enriched MQL helps in retaining the tool's sharpness for a longer period due to the formation of hard oxide layer formation on the tool. The cutting tool under MQL with an oxygen environment removes 40% more material when compared to the conventional MQL with air for the same average flank wear width of 0.3 mm.

A COMPREHENSIVE REVIEW ON MINIMUM QUANTITY LUBRICATION IN TURNING PROCESS

The physical health of human beings and the environment will be negatively influenced by the improper use of cutting fluid, which is an important factor for achieving sustainable machining. Turning is a basic process of all machining operations. Using a minimum quantity lubrication (MQL) system is the best way for achieving sustainable turning process. Improvements made in the MQL system to achieve better performance of the turning process have been discussed in this paper. Search categories that have been used to carry out the study are MQL system with the conventional cutting fluid, MQL system with nano-fluid, MQL system with cryogenics and restructured MQL system. The advancements in MQL turning process published over a span of four most recent years from 2018 to 2021 have been chosen for this review. In this study, the details of experimentation such as materials used for the workpiece, cutting tool materials, environments for lubrication, machining parameters, MQL fluids and performance parameters such as surface roughness, tool wear, cutting force, cutting temperature, etc. have been critically considered. Results investigated from various articles mostly show that advanced MQL systems such as MQL system with nano-fluid, MQL system with cryogenics and restructured MQL system are better than the conventional MQL system in terms of producing better output performance.

Theoretical and experimental study of the chatter vibration in wet and MQL machining conditions in turning process

Turning is one of the most commonly used cutting processes for manufacturing components in production engineering. The turning process, in some cases, is accompanied by intense relative movements between tool and workpiece, which is called chatter vibrations. Chatter has been identified as a detrimental problem that adversely impacts surface finish, tool life, process productivity, and dimensional accuracy of the machined part. Cooling/Lubrication in the turning process is normally done for some reasons, including friction and force reduction, temperature decrement, and surface finish improvement. Wet cooling is a traditional cooling/lubrication process that has been used in machining since the past. Besides, a variety of new cooling and lubricating approaches have been developed in recent years, such as the minimum quantity lubrication (MQL), cryogenic cooling, nanolubrication, etc., due to ecological issues. Despite the importance of cooling/lubrication in machining, there is a lack of research on chatter stability in the presence of cutting fluid in cutting processes. In this study, the chatter vibration in turning process for two cooling/lubrication conditions of conventional wet and MQL is investigated. An integrated theoretical model is used to predict both the metal cutting force and the chatter stability lobe diagram (SLD) in turning process. This model involves deriving a math equation for predicting metal cutting force for both wet and MQL conditions using experimental training force data and a Genetic Expression Programming (GEP)-based regression model. Also, the traditional single degree of freedom chatter model is used here for predicting the SLDs. The chatter model is discussed and verified with experimental tests. Then, the experimental results of the tool's acceleration signal, work surface texture, surface roughness, chip shape, and tool wear are presented and compared for wet and MQL conditions. The results of this study show that the cooling/lubrication systems such as wet or MQL have a considerable effect on the SLDs. Also, the predicted results of metal cutting force and SLD for both wet and MQL techniques are in good agreement with the experimental data. Therefore, it is recommended that for each lubrication condition including wet, or MQL, the SLD be determined to achieve higher machinability.

A novel approach to improve environmentally friendly machining processes using ultrasonic nozzle–minimum quantity lubrication system

In minimum quantity lubrication (MQL) machining, a small quantity of cutting fluid is air-atomized to generate fine liquid droplets, and they are injected into the machining zone. The effectiveness of the MQL system depends on the droplet size/distribution, spray shape, spray velocity, and area fraction covered by the droplets. In the present study, for the first time, a novel MQL nozzle has been designed and manufactured applying ultrasonic vibrations using piezoelectric discs tighten on the nozzle between the mechanical amplifying element and a support element. Ultrasonic vibrations can be used to effectively atomize the cutting fluid into fine and uniform-sized droplets and smaller spray angle with a larger spray deposition distance. Ultrasonic nozzle–minimum quantity lubrication (UN-MQL) system generates a mist-like uniform spray. The ultrasonic nozzle was designed and analyzed using the SolidWorks and Ansys Workbench software. Image processing techniques have been used to characterize the droplet sizes, and the droplet distribution after the oil has been sprayed onto a polished lead-coated plate by UN-MQL system as well as better understanding in the application of the ultrasonic nozzle for its effective use in practical industrial applications. A set of experiments have been conducted on AISI 304L stainless steel during turning with the developed setup, and the results have been compared with dry, wet, and conventional MQL turning processes. The fine droplets produced by the UN-MQL system penetrate effectively into the machining zone and consequently enhance the cooling-lubrication characteristic in the cutting zone. Spray angle of UN-MQL in comparison to conventional MQL systems decreased about 40% and 30% in air pressure of 6 and 3 bar, respectively. The rising inclination of the area fraction covered by droplets in variable air pressures has improved approximately 70% among the oil flow rates of 16 to 110 ml/h in the UN-MQL case as opposed to the conventional MQL system. The greatest quantity of decrement in mean droplet diameter which transpired in air pressure of 1 bar, reached nearly 63% for the oil flow rates of 16 ml/h, 30 ml/h, and 43 ml/h. Overall, the results obtained during UN-MQL turning experiments show that the surface roughness has been improved compared to dry, flood, and conventional MQL turning processes.

Machining Performance of Inconel 718 Under Dry, MQL, and Nanofluid MQL Conditions: Application of Coconut Oil (Base Fluid) and Multi-walled Carbon Nanotubes as Additives

The present work intends to investigate the application potential of coconut oil, as cutting fluid, during metal machining of a nickel-based superalloy. In doing so, machining performance of difficult-to-cut aerospace superalloy Inconel 718 is studied under dry, minimum quantity lubrication (MQL), and nanofluid MQL (NFMQL) using uncoated WC–Co tool, operated at varied cutting speeds. MQL environment is created by supplying air-oil mist in which commercially available coconut oil is used as cutting fluid. On the other hand, nanofluid is prepared by dispersing a specific concentration of multi-walled carbon nanotubes within coconut oil. Machining performance as observed in MQL and NFMQL is compared to that of dry machining. The following machining performance indicators are considered herein: cutting force magnitude, tool-tip temperature, and width of flank wear progression. In addition, studies on dominant modes and mechanisms of cutting tool wear, chip morphology (macro/micro), and surface roughness of the machined work part are also carried out. In the purview of machined surface roughness, it is concluded that NFMQL performs better than dry machining and conventional MQL. Flank wear is witnessed more severe during dry machining than MQL/NFMQL. However, beyond 83 m/min cutting speed, conventional MQL outperforms NFMQL (with 0.2 wt% nano-additives concentration) machining, from the viewpoint of flank wear width.

Studies on chip morphology and modes of tool wear during machining of Ti-6Al-4V using uncoated carbide tool: application of multi-walled carbon nanotubes added rice bran oil as nanocutting fluid

In this work, machining performance of Ti-6Al-4V is studied in consideration with cutting force, tool-tip temperature, tool wear mechanisms, chip morphology and roughness of the machined surface. Machining experiments are carried out by varying cutting speed (Vc) with constant feed and depth-of-cut. Uncoated WC-Co insert is used as cutting tool. Multi-walled carbon nanotubes (MWCNTs) added rice bran oil is utilized to produce nanofluid minimum quantity lubrication (MQL) environment. Chip morphology along with measurable geometrical parameters including chip-tool contact length, equivalent chip thickness (H ch), segmentation spacing, segmentation frequency, shear band width, shear angle, chip hardness, etc. are studied in detail. Effects of Vc on cutting force, tool-tip temperature, depth of flank wear, and area of crater wear are discussed. Different tool wear mechanisms are identified as well. It is experienced that nanofluid MQL (NFMQL) outperforms traditional dry cutting as well as conventional MQL in purview of improved process performance.

Dry, MQL, and Nanofluid MQL Machining of Ti–6Al–4V Using Uncoated WC–Co Insert: Application of Jatropha Oil as Base Cutting Fluid and Graphene Nanoplatelets as Additives

Nanocutting fluids are very popular due to their excellent thermo-physical and tribological properties which provide adequate cooling and lubrication during metal cutting. Conventional dry machining of difficult-to-cut superalloy Ti–6Al–4V faces several challenges. To overcome this, application of cutting fluid is indeed a necessity. However, performance of conventional minimum quantity lubrication (MQL) system, in which air–oil mist is sprayed into cutting zone, is somewhat limited due to inadequate penetration into tool–work and tool–chip interfacial regions, especially at high cutting speeds. MQL performance can further be enhanced by applying nanocutting fluid in which nano-sized additives are dispersed into the base cutting fluid; this is known as nanofluid MQL (NFMQL). In order to take care of several alarming issues related to environmental protection and occupational health hazards, the present study explores application feasibility of biodegradable Jatropha oil added with graphene nanoplatelets as nanocutting fluid. Machinability of Ti–6Al–4V is assessed under NFMQL; results are compared to that of dry and conventional MQL machining. Cutting force magnitude, tool-tip temperature, morphology of worn-out insert, chip’s macro/micro-morphology and surface roughness of the machined work part, etc., are studied in detail. For MQL and NFMQL, tool wear morphology detects existence of ‘unaffected zones’ which indicates sustenance of strong hydrodynamic tribo-film of cutting fluid, thus protecting the insert against wear. Up to 82 m/min cutting speed, NFMQL causes lower tool flank wear than dry and conventional MQL. On the other hand, superior machined surface finish is obtained under NFMQL up to 106 m/min cutting speed.

Development and Performance Evaluation of Eco-Friendly POSS-Containing MQL Oil Coolant for Drilling Processes

Drilling work on Inconel, a well-known super-heat-resistant alloy, requires a significant quantity of cutting oil to prevent heat-induced abrasion and damage to the cutting tool, caused by the strength and toughness of the alloy. This high requirement of cutting oil, however, negatively affects the processing environment; therefore, minimum-quantity lubrication (MQL), an eco-friendly cutting-oil-supply method, is attracting attention. The conventional MQL method, however, has the disadvantage that an oil-mist is produced along with high-pressure air; hence, the mist is scattered in the air, making the application of the oil to the cutting point inefficient and rendering the cooling effect to be less than that in wet processing. In this study, therefore, an eco-friendly compound, polyhedral oligomeric silsesquioxane (POSS)—a nanostructured organic–inorganic hybrid material that exhibits better adhesion to materials than conventional MQL-specific oil and is resistant to the heat generated during drilling—was developed by adding POSS to the conventional MQL-specific oil, and the effects were verified.

Initial investigation on Surface Integrity when Machining Inconel 718 with Conventional and Electrostatic Lubrication

Inconel 718 is largely used in high-temperature applications where high hot strength and hardness are required, such as in aerospace and oil & gas industries. The majority of parts made from Inconel718, especially in the aerospace industries, are safety-critical components where surface quality is of significant importance. In industrial practice, the development of satisfactory surface integrity for high-performance applications of Inconel 718 is still a difficult process when machining parts with conventional cutting fluid. However, a potential alternative to conventional cooling is Minimum Quantity Lubrication (MQL), since it avoids large amounts of cutting fluid, and enhances the functional behaviour of machined components through superior surface quality. In addition, further improvements can be achieved with electrostatic lubrication (EL). With EL, the lubricant is electrosprayed increasing penetrability, atomization, deposition and wettability in the machining area. In this paper, a nozzle designed for electrostatic spraying using MQL is presented. The effects of EL on surface integrity are discussed in comparison with conventional MQL and Flood strategies. Machining experiments have been carried out in line with finishing conditions analogous to those adopted in industry for the milling of nickel-based super alloys. For these experiments, MQL and EL are supplied with the same setup, except for charging conditions. Surface integrity characteristics such as roughness, hardness and surface defects are investigated together with power consumption and tool life.

The influence of single-channel liquid CO2 and MQL delivery on surface integrity in machining of Inconel 718

Sustainable machining of difficult-to-cut materials requires effective cooling and lubrication techniques. To substitute conventional flood cooling and lubrication, different techniques such as cryogenic cooling and/or minimum quantity lubrication (MQL) can be used. Liquid carbon dioxide (LCO2) can be pre-mixed with different lubricants before its delivery to the cutting zone. This article investigates the influence of this recently developed cooling and lubrication method on surface integrity characteristics in milling of Inconel 718. Surface roughness, surface topography and microstructure were evaluated for flood lubrication, dry cutting and LCO2 machining using a single-channel LCO2 and MQL strategy. Moreover, two different lubricants were evaluated for MQL: (i) conventional MQL oil and (ii) solid lubricant molybdenum di-sulphide (MoS2). In addition to being environmentally friendly, MoS2 lubricated LCO2 showed comparable surface characteristics to flood lubrication. Also, the use of lubricated LCO2 resulted in higher part surface cleanliness compared to flood lubrication.

Machining characteristics based life cycle assessment in eco-benign turning of pure titanium alloy

Abstract Minimum quantity lubrication (MQL) is considered as an eco-benign, greener, and socio-economic alternative to dry cutting. Nevertheless, its effectiveness is limited to mild cutting materials owing to less generation of heat during machining. In order to address this challenge regarding hard-to-cut materials, energy requirement, and material flow, Ranque-Hilsch Vortex Tube assisted Minimum Quantity Cutting Fluids (RHVT-MQCF) has been practiced in the turning of pure titanium and compared its effectiveness with conventional MQL cooling techniques. The turning experiments were performed on pure titanium alloy by varying the cutting speed (250–300 m/min), feed rate (0.05–0.13 mm/rev), and depth of cut (0.3–0.5 mm), respectively. In addition, a statistical modeling technique and desirability function approach was used to analyze and optimize the sustainable indicators for the machining process associated with the cutting force, power consumption, specific cutting energy, chips morphology, material removal rate, and surface quality (i.e. surface roughness). Regarding sustainability performance, Life Cycle Assessment (LCA) model was applied using Simapro 8.3 software connected to EPS 2000 and ReCiPe Endpoint v1.12 databases. Findings have depicted the high performance of RHVT-MQCF conditions regarding machining characteristics compared to MQL under same conditions. In-depth analysis has shown that RHVT-MQCF is a sustainable and useful alternative to the manufacturing sector.

Development of an ultrasonic vibration assisted minimum quantity lubrication system for Ti-6Al-4V grinding

Minimum quantity lubrication (MQL) is widely used in machining/grinding as a competent cooling-lubrication technique owing to its advantages in terms of better cooling, lubrication, and lower coolant consumption. Ultrasonic vibration can be used to enhance the efficiency of MQL system by atomising the cutting fluid into fine and uniform droplets. In this study, an ultrasonic vibration assisted MQL (UAV-MQL) system is indigenously developed to effectively atomise the cutting fluid using the ultrasonic vibration of a suitably designed horn. To check the effectiveness of the developed UAV-MQL system, a set of experiments have been conducted on Ti-6Al-4V alloy during surface grinding operation, and the results have been compared with dry, flood and air-assisted conventional MQL grinding process using soluble oil as a cutting fluid.

Application of minimum quantity lubrication with addition of water in the grinding of alumina

Among the alternatives to reduce the application of cutting fluid in machining industry, minimum quantity lubrication (MQL) technique has been promising, although it can impair cooling properties and the ability of the fluid to penetrate the cutting region. In order to further reduce the quantity of oil and to improve the characteristics of the cooling lubrication method, this work aims to compare the effect of MQL with different ratios of oil/water (1:1, 1:3, and 1:5) on the performance of plunge cylindrical grinding of alumina. Lubricating effect and effective penetration of fluid in the cutting zone are considered the most relevant factors. The lowest surface roughness value was obtained with the application of conventional flood cooling, followed by MQL 1:1. In comparison to conventional MQL technique, reduced surface roughness and grinding wheel wear could be obtained by applying MQL with water.

Effects of Machining and Oil Mist Parameters on Electrostatic Minimum Quantity Lubrication–EMQL Turning Process

A cost-effective and eco-friendly alternative to conventional flood cooling-lubrication and minimum quantity lubrication (MQL) is electrostatic minimum quantity lubrication (EMQL). EMQL, which is a novel green machining technology that utilizes the synergetic effects between electrostatic spraying (ES) and MQL, has been successfully shown a potential in milling process. However, the effective application of EMQL is not only connected with machining parameters, such as cutting speed and feed rate, but also related to oil mist parameters including charging voltage, lubricant flow rate, air pressure, and nozzle position and distance. This paper investigated the effect of the above parameters on the cutting performance of EMQL turning stainless steels in comparison with completely dry and conventional wet and MQL cutting. The results suggested that cutting speed and voltage were important factors affecting the effectiveness of EMQL, and found that there were the optimum air pressure and nozzle position and distance when EMQL turning AISI 304 stainless steel. Properly selecting these parameters, a viable alternative to wet and MQL cutting could be achieved by promoting lubricants into cutting interface to reduce friction and adhesion of work-piece materials on the interface.

Experimental evaluation on the effect of electrostatic minimum quantity lubrication (EMQL) in end milling of stainless steels

ABSTRACTThe machining of stainless steels is very challenging owing to their high toughness and low thermal conductivity, causing high cutting temperatures and rapid tool wear. Conventionally, metalworking fluids in flood form are used during the process to improve surface quality and tool life; however, their use raises issues including environmental pollution and economic concerns. Therefore, an electrostatic minimal quantity lubrication (EMQL) technology was developed to reduce the consumption of metalworking fluids. EMQL is a near-dry machining technology utilizing the synergetic effects between electrostatic spraying and minimum quantity lubrication (MQL), wherein the lubricant is to apply in a form of fine, uniform and highly penetrable and wettable mist droplets directly to the cutting zone. This study investigates the effect of EMQL in end milling of AISI 304 stainless steel in comparison with dry, wet and MQL machining. The results suggest that EMQL reduces tool wear and cutting force, prolongs tool life considerably and enhances surface finish compared with conventional wet and MQL machining. scanning electron microscopy and Energy-dispersive X-ray spectroscopy analyses show that EMQL considerably reduces adhesive and abrasive wear on the flank face because of the lower friction and heat generation resulting from more efficient entry of the lubricant into the cutting interfaces.

A Review of Minimum Quantity Lubrication Technique with Nanofluids Application in Metal Cutting Operations

Minimum quantity lubrication (MQL) technique did not only serve as a better alternative to flood cooling during machining but enhance better surface finish, minimizes the cost, reduces the impact loads on the environment and health hazards on the operation personnel. However, the coolant or lubrication media used in MQL technique posed certain restrictions especially at very high cutting speeds where the lubricating oil tends to evaporates as it strikes the already heated cutting tool at elevated temperature. Desire to compensate for the shortcomings of the lubricating media in the MQL technique led to the introduction of nanoparticles in the cutting fluids for use in the MQL lubrication process. Nanoparticles have much higher and stronger temperature-dependent thermal conductivity and enhanced heat transfer coefficient at very low particle concentration, which are key parameters for their enhanced performance in many of the machining applications. Optimizing the nanoparticles concentration leads to efficiency in most of their application. Their ball bearing effect lubrication at the cutting zone through formation of film layer which reduces friction between the contact surfaces thereby reducing cutting force, temperature and tool wear. It has been reported in various studies that nanoparticles introduction in cutting fluids led to excellent machining performance in reduction of cutting forces, reduced tool wear, reduced cutting temperature and improved surface finish of the work piece thereby increasing productivity and reduction of hazards to the health of personnel and the environment better than the pure or conventional MQL process. Thus, the application of various nanoparticles and its performances in metal cutting operations with respect to the cutting forces, surface finish, tool wear and temperature at the cutting zone are evaluated and highlighted.

A study on process parameters in end milling of AISI-304 stainless steel under electrostatic minimum quantity lubrication conditions

Effective lubrication and cooling are very critical to control friction and heat generation in metal-cutting processes. Conventionally, cutting fluids in flood form are employed during the processes; however, their usage is frequently seen to raise major environmental, economic, and employees’ health concerns. All these factors have urged researchers to search for alternatives to minimize or even eliminate cutting fluid usage. To serve that purpose, a new near-dry machining technique called “electrostatic minimum quantity lubrication” (EMQL) has been innovated and developed. EMQL is a technique using the synergetic effects between electrostatic spraying (ES) and minimum quantity lubrication (MQL), wherein a very small amount of lubricant, negatively charged by the electrostatically contact charged method, is directed into the machining area in the form of a fine, uniform, and highly penetrable and wettable oil mist. The focus of this study is to evaluate the performance of EMQL in end milling of AISI-304 stainless steel in terms of tool wear, cutting force, tool life, and surface roughness. The influence of EMQL process parameters such as charging voltage, air pressure, lubricant flow rate, and cutting speed is determined based on an experimental study. A comparison with the results obtained in completely dry, wet, and MQL machining is also provided. The experimental results show the effectiveness of EMQL as a viable alternative to conventional wet and MQL machining through the reduction in the friction at the tool–chip interface. It is found that the charging voltage is an important factor influencing the effective application of EMQL oil mist. EMQL with −5 kV voltage is recommended because it provides not only lower tool wear and cutting force but also higher tool life and better surface finish. In addition, it is found that there are the optimum lubricant flow rate and air pressure in end milling of AISI-304 stainless steel with EMQL. The proper selection of the above parameters can lead to a low-cost and eco-friendly machining.

Experimental investigation of machining parameter under MQL milling of SS304

Minimum quantity lubrication (MQL) or near dry machining has been recognized by many researchers and industrialist in order to move one step ahead towards the green manufacturing. MQL assisted machining reduces the harmful environmental impact caused by flood coolant and machining cost. In this paper an attempt has been made to study the impact of oxygen as a carrier gas in MQL during end milling of austenitic stainless steel grade SS304. Also, the machining performance under conventional MQL with air and dry machining have been studied. The evaluation was done on tool wear, surface roughness and cutting forces under two distinct cutting speeds i.e. 75 m/min and 100 m/min. Investigation brings to light that presence of oxygen is susceptible in the case of machining of SS304, it provides extra protective oxide layer near the tool chip interface. Consequently, increased tool life, reduced surface roughness and cutting forces when compared to conventional MQL assisted milling.