Minimum Quantity Lubrication Research Articles

Assessing the performance of ionic liquid-assisted minimum quantity lubrication during machining of biomedical-grade stainless steel with recently developed AlTiN/TiSiXN-coated carbide tool

Assessing the performance of ionic liquid-assisted minimum quantity lubrication during machining of biomedical-grade stainless steel with recently developed AlTiN/TiSiXN-coated carbide tool

Vegetable oils in minimum quantity lubrication: a comparative analysis of properties and performance

Vegetable oils in minimum quantity lubrication: a comparative analysis of properties and performance

Performance assessment of the multi-nozzle injection MQL system for cleaner machining of hardened AISI D2 steel concerning power consumption

ABSTRACT Sustainable hard machining is a pressing need in manufacturing industries for techno-social, economic and environmental benefits to machine difficult-to-cut materials. Thus the present study investigates finish turning of hardened AISI D2 steel using a MTCVD coated carbide insert (TiN-TiCN-Al2O3) with geometry CNMG120408FW and grade WK05CT under a multi-nozzle MQL system using LRT 30 mineral oil (50 ml/hr flow rate, 6 bar compressed air pressure, 30 mm nozzle distance from tool tip) for minimal quantity lubrication at both the rake and flank zones for assessment of machinability. Flank wear lies between 0.79 and 0.155 mm and within the failure criterion limit of 0.2 mm. Arithmetic surface roughness trials have been within 0.361–0.877 microns and within the 1.6 microns acceptable range. The cutting temperature has been between 80.7°C and 226.9°C and even below 200°C in the majority of runs. The cutting power lies within 0.432kW–0.804kW. The optimal parametric combination has been found to be d=0.1 mm, f=0.05 mm/rev and v=80 m/min respectively and improvement has been observed over dry cutting. RSM models are found to be statistically significant. Application of multi-nozzle MQL in machining of hardened steel outperformed through machinability assessment and may be adopted in shopfloor for sustainability..

Combination of minimum quantity lubrication (MQL) with solid lubricant (SL): challenges, predictions and implications for sustainability

This literature review explores minimum quantity lubrication (MQL) machining, emphasizing its benefits over traditional dry and flooded cooling methods. MQL is vital in manufacturing, enhancing productivity and sustainability. Adding solid lubricants (SL) amplifies MQL’s advantages. This article identifies challenges in MQL + SL machining and outlines future research opportunities. A comprehensive four-step review was conducted: identifying research gaps, determining databases and search terms, defining paper selection methods and performing bibliometric analysis. The review abstracted information from selected articles, offering in-depth discussions. Challenges in MQL machining involve forces, temperature, tool wear, roughness and lubricant performance. Studies show incorporating SL into base fluids mitigates these issues. Sustainability is a core focus in modern manufacturing, and MQL’s eco-friendly reputation is deserved. MQL with SL, often in nanoparticle form, provides benefits like reduced friction, enhanced tool life, lower energy consumption and improved material disposal. In conclusion, MQL + SL machining offers a promising path to balance productivity and sustainability. Continued research and development are essential to overcome challenges and unlock its full potential. As manufacturing evolves, MQL + SL machining exemplifies innovation and sustainability, poised to reshape the industry’s future.

Graphene nanoplatelets-water nanofluids: A sustainable approach to enhancing Ti-6Al-4V grinding performance through minimum quantity lubrication

This study introduces a stable, water-based graphene nanoplatelets (GNPs) nanofluid as a sustainable cutting fluid for grinding Ti-6Al-4V alloy under minimum quantity lubrication (MQL). Using ethanol and sodium deoxycholate (SDOC) surfactant, the dispersion stability of GNPs in water was remarkably extended from 1 h to 57 days. This novel nanofluid formulation enhances wettability, thermal conductivity, and tribological properties. Grinding tests showed a 0.35 mg/mL water-GNPs concentration reduced grinding forces by 74.44 % and 33.37 % compared to dry and conventional flood lubrication, respectively, while improving surface roughness. Raman spectroscopy confirmed graphene's presence on the machined surface, highlighting the potential of water-GNPs nanofluids as an eco-friendly alternative to traditional metalworking fluids, enhancing sustainability in manufacturing.

Research on Tool Wear and Machining Characteristics of TC6 Titanium Alloy with Cryogenic Minimum Quantity Lubrication (CMQL) Technology

Titanium alloys are crucial in precision manufacturing due to their exceptional properties, but traditional machining methods lead to tool wear, deformation, and high costs. Conventional cooling fluids reduce heat but cause environmental issues, necessitating more sustainable solutions. Cryogenic Minimum Quantity Lubrication (CMQL) technology, using liquid nitrogen or carbon dioxide with minimal amounts of cutting fluid, offers an eco-friendly alternative that reduces machining temperatures and friction. This study tested the TC6 titanium alloy under conventional and CMQL conditions, focusing on tool wear, surface quality, and machining efficiency. Results showed that CMQL significantly decreased tool wear and surface roughness, with a 42% reduction in surface roughness during drilling and a 20–30% efficiency increase. The findings highlight CMQL’s potential to improve machining quality and efficiency while promoting environmentally friendly practices in the industry.

A Review of High-Speed Turning of AISI 4340 Steel with Minimum Quantity Lubrication (MQL)

AISI 4340 is a medium-carbon low-alloy steel that has gained distinctive attention due to its advanced properties including high strength, high toughness, and heat resistance. This has led to its commercial usage in a wide variety of industries such as construction, automotive, and aerospace. AISI 4340 is usually machined in a hardened state through a hard-turning process, which results in high heat generation, accelerated tool wear, low productivity, and poor surface quality. The application of high-speed machining helps improve the material removal rate and surface finish quality, yet the elevated temperature at the cutting zone still poses problems to the tool’s lifespan. Apart from using advanced cutting tool materials, which is costly, researchers have also explored various cooling methods to tackle the heat problem. This paper presents a review of a sustainable cooling method known as minimum quantity lubrication (MQL) for its application in the high-speed turning of AISI 4340 steel. This study is centered on high-speed turning and the application of MQL systems in machining AISI 4340 steel. It has been observed that the hard part turning of materials with a hardness exceeding 45 HRC offers advantages such as improved accuracy and tighter tolerances compared to traditional grinding methods. However, this process leads to increased temperatures, and MQL proves to be a viable alternative to dry conditions. Challenges in optimizing MQL performance include fluid penetration and lubrication effectiveness.

Machining and Sustainability Performance Comparison for the Milling Process of Al6082 Alloy Under Various Minimum Quantity Lubrication Conditions

Machining and Sustainability Performance Comparison for the Milling Process of Al6082 Alloy Under Various Minimum Quantity Lubrication Conditions

Preparation and cutting performance of (W,Ti,Ta)C/CaF2 nano-self-lubricating cermet tool material via spark plasma sintering

To improve the machining surface integrity of HT250 gray cast iron, (W,Ti,Ta)C based nano-self-lubricating cermet tools containing nano CaF2 were successfully prepared by spark plasma sintering (SPS). When the content of nano CaF2 was 5 vol%, the flexural strength, hardness, and fracture toughness of (W,Ti,Ta)C/CaF2 nano-self-lubricating cermet tool were 1134 ± 39 MPa, 18.97 ± 0.22 GPa and 8.52 ± 0.33 MPa·m1/2, respectively. The cutting experiments were carried out by minimum quantity lubrication (MQL), and the effects of nano CaF2 content and MQL on cutting performance were studied. The cermet tool with 5 vol% nano CaF2 had the optimized cutting performance under MQL conditions, with cutting forces FX, FY, and FZ reduced by 20.5%, 37.9%, and 33.3%, respectively, cutting temperature decreased by 34.8%, and tool life increased by 16.7%. The solid-liquid dual lubrication cutting method combined with the solid lubrication CaF2 and MQL effectively reduced the thickness and oxidation degree of the work hardening layer. The optimized surface roughness of the workpiece after machining was 0.89 ± 0.05 μm, which is 27.6% lower than that of dry cutting.

Optimization of cutting parameters using response surface methodology (RSM) in milling Inconel 718 superalloy using Borax-added nanofluid in (MQL) system

PurposeThe need for materials with superior mechanical and physical properties has recently increased. Inconel 718, one of these superalloys, is frequently used in the aviation and space industry. However, during Inconel 718 superalloy machining, cutting tools and cutting fluid were excessively consumed. This study aims to investigate using an innovative and environmentally friendly cutting fluid in milling the Inconel 718 superalloy.Design/methodology/approachIn this study, a Borax- (BX-)added cutting nanofluid was prepared and used for the first time as a coolant in the minimum quantity lubrication (MQL) system of Inconel 718’s face milling process. Response surface methodology (RSM) was used to determine the effect of the BX element on cutting performance. Face milling operations were carried out by adding BX elements at 1.5% and 3% at two different rates.FindingsAs the BX additive ratio in the cutting fluid used in the MQL system increased, the cutting force values decreased. The lowest cutting force value was measured in the tests with cutting fluid containing 1.5% BX. In addition, a smoother surface was obtained by adding 1.5% BX to the cutting fluid. Furthermore, cutting tool life increased by 20% compared to 0% by 3% BX nanofluid concentration.Originality/valueThe study is innovative regarding the material processed, the cutting fluid used and the method used for the aerospace industry.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2024-0191/

A comprehensive investigation on eco-benign grindability improvement of Inconel 625 using nano-MQL

This work uses an alumina wheel to investigate the eco-benign grinding for better surface integrity of Inconel 625 (IN 625). To achieve this, applying nanofluids (NFs) with the minimum quantity lubrication (MQL) principle has been adopted, aiming at eco-benign grinding practices. In this work, MoS2 NFs, MWCNTs NFs and hybrid NFs (prepared by mixing MoS2 and MWCNTs in a 1:1 ratio) prepared using deionized water as the base fluid have been used. An in-house developed MQL setup is used to aim the NFs inside the grinding zone. The first attempt has been made to grind IN 625 in these environments. The characterisation of NFs in terms of nanofluid stability, dynamic viscosity, thermal conductivity and surface wettability have been performed before their utilization in grinding operations. A comparison has been made between the results obtained from NFs grinding and those from dry and soluble oil-based MQL grinding. It has been found that hybrid NFs provide excellent lubrication and cooling effects, reducing grinding forces and improving surface quality. Moreover, scanning electron microscopy, energy-dispersive spectroscopy and X-ray photon spectroscopy are applied to investigate the ground surfaces under different grinding conditions. Also, residual stress (with the help of X-ray diffraction and electron backscattered diffraction) and microhardness have been determined to gain further insights into the grinding behaviour. The wheel and chip morphology analyses have been performed to support the findings. The findings from this investigation lead to the conclusion that applying nano-MQL improves grinding effectiveness and promotes cleaner grinding outcomes. Hybrid NFs prove especially effective, as the physical synergistic effect enhances and safeguards the surface integrity of the produced ground components.

Formation mechanism of blade surface integrity based on hybrid process of cryogenic minimum quantity lubrication and ultrasonic rolling strengthening process

This study proposes a hybrid process method based on Cryogenic Minimum Quantity Lubrication and Ultrasonic Rolling Strengthening Process (CMQL-URSP) to improve the surface integrity and enhance the mechanical properties of blade surface. First, the principle of the CMQL-URSP hybrid process was described. Second, the TEM experiments were conducted to clarify the influence of the CMQL-URSP hybrid process on aircraft engine blades. Finally, the blade processing experiments were performed to demonstrate the effectiveness of the CMQL-URSP hybrid process on the blade surface micro-morphology, micro-hardness and residual stress. The results indicate that the CMQL-URSP hybrid process effectively overcomes the limitations inherent to the solitary application of URSP. The CMQL process inhibits work hardening, thereby allowing the URSP to achieve better low-plastic surface improvement. Grain refinement governed by the continuous dynamic recrystallization mechanism leads to the formation of nanocrystals, which significantly improves mechanical properties of blade surface. The CMQL-URSP hybrid process results in a reduction in surface roughness from Ra 2.644 μm to Ra 0.055 μm, an increase in surface residual compressive stress from 321 MPa to 657 MPa, and the formation of a reinforced layer with a depth of 3.7 mm on the blade, thereby enhancing the surface integrity of the blade.

Experimental research on sustainable drilling of Hastelloy X superalloy: Impact of hBN, GNP, LN2 and hybrid eco-friendly cooling/lubrication strategies

In this study, the effect of sustainable cooling and lubrication strategies such as MQL, LN2, LN2 +MQL, LN2 +hBN/GA, LN2 +GNP/GA, LN2 +hBN-GNP/GA on drilling nickel-based Hastelloy X alloy was examined. The environmental impacts and health risks of traditional petroleum-based cutting fluids used in drilling operations have led researchers to look for ecological alternatives. In this context, combinations of nanofluids enriched with minimum quantity lubrication (MQL), liquid nitrogen (LN2), and nanosized hBN and GNP particles have been tested. The experiments were carried out at cutting speeds of 20 and 30 m/min and feed rates of 0.04 and 0.06 mm/rev. Nanofluids characteristics i.e., viscosity, Ph, thermal conductivity and wettability, and drilling performance were evaluated with criteria such as cutting force, surface roughness, hole quality and tool wear. The results obtained showed that the hybrid methods combining LN2 and nanofluid-based MQL provided superior performance in terms of both cooling and lubrication, and the condition directly positively affected the processing outputs. This study contributes to the literature by revealing the potential of ecological cooling/lubrication methods in the sustainable production of difficult-to-machine materials such as Hastelloy X.

Comparison of sustainable cooling/lubrication strategies for drilling of wire arc additively manufactured Inconel 625

Machining Inconel presents significant challenges due to the material's high strength, hardness, and heat resistance. These properties often result in accelerated tool wear, modest surface finish, and increased energy consumption during machining processes. Despite its widespread use in industries, the machining of Inconel alloys remains a persistent bottleneck in manufacturing operations. In this study, we focus on drilling rather than milling of Inconel 625, a commonly used nickel-based superalloy, due to its specific relevance in various industrial applications. Drilling operations are critical in numerous contexts, including the fabrication of aerospace components, where precision, hole quality, and efficiency are paramount. Therefore, this study aims to improve machinability of wire arc additively manufactured Inconel 625 by fabricating it with two different travel speeds, 175 mm/min and 185 mm/min as well as by drilling the fabricated Inconel 625 using recently developed sustainable lubrication/cooling strategies, i.e. electrostatic minimum quantity lubrication (EMQL) and cryogenic LCO2. The results show that the sample built with 185 mm/min produces less tool wear, surface roughness, thrust force and power consumption. The use of LCO2 results in approximately 35 % less tool wear, 27 % less surface roughness, 15 % less thrust force, and 4 % lower power consumption compared to EMQL for the sample built at 185 mm/min.

OPTIMISATION OF A NEEM OIL BASED MINIMUM QUANTITY LUBRICATING (MQL) SYSTEM PARAMETERS FOR THE ORTHOGONAL MACHINING OF MILD STEEL

Cutting tools experience early failure and dimensional variation due to the high temperature developed during machining. Conventional cutting fluid applications do not successfully remove heat because they do not reach the chip-tool contact. Operators on the work floor may experience the adverse side effects of cutting fluids, such as skin and respiratory issues. As a result, a different lubricating method is necessary for machining without harming the tool-workpiece, which would also be advantageous for health and the economy. This research aims to develop and evaluate the efficiency and optimization of minimal use of Neem seed oils as lubrication for the Taguchi L9 array-based design for machining of mild steel. The Taguchi optimization technique was used to examine the impact of the neem oil based Minimum quantity lubrication (MQL) system (with flow rate, air pressure and nozzle diameter as factors) on the workpiece temperature and chip thickness ratio at cutting speeds of 260 rpm and 470 rpm. The outcome demonstrated that optimal settings at 260 rpm were a flow rate of 50 ml/hr, air pressure of 1.5 bars, and nozzle diameter of 0.8 mm for workpiece temperature, and a flow rate of 100 ml/hr, air pressure of 1 bar, and nozzle diameter of 0.8 mm for chip thickness ratio. At 470 rpm, optimal settings for workpiece temperature were a flow rate of 50 ml/hr, air pressure of 1.5 bars, and nozzle diameter of 0.5 mm, while chip thickness ratio optimization indicated a flow rate of 100 ml/hr, air pressure of 1 bar, and nozzle diameter of 0.5 mm.

Improving the performance of cutting fluids by using ZnO and ZrO2 nanoparticles

Sustainability is nowadays a global research priority, especially in machining, where optimizing production processes for increased productivity, profits, and efficiency is key. Addressing this need, the adoption of nanofluids in minimum quantity lubrication machining has surged, aligning with environmental concerns and regulatory demands. In this study, sustainable zinc oxide (ZnO) and zirconium dioxide (ZrO2) nanoparticles fabricated using plant extracts have been incorporated into conventional cutting fluids to enhance their machinability performance under minimum quantity lubrication for turning process. The microstructural analysis confirms the successful synthesis of the targeted nanoparticles with excellent purity and size distribution. The addition of nanoparticles significantly enhanced thermal conductivity from 0.5916 W/(m⋅K) for the base fluid to 0.6286 W/(m⋅K) for ZnO and to 0.6242 W/(m⋅K) for ZrO2. Further, nanofluids exhibited an increased dynamic viscosity, 1.435 mPa.s for ZrO2 and 1.125 mPa.s for ZnO as compare to 0.7644 mPa.s of base fluid, attributed to the nanoparticle confinement effect whereas contact angle measurements indicated an improved wettability for all nanofluids. Machining experiments validate the efficacy of nanofluids, demonstrating reduced cutting temperatures and enhanced surface finish. Notably, ZrO2-based nanofluids exhibit improved tribological response, while ZnO-based nanofluids showcase exceptional heat transfer ability, offering promising solutions to key technical challenges in machining processes. In conclusion, this study underscores the potential of green, sustainable ZnO and ZrO2 nanoparticles as additives in cutting fluids, poised to revolutionize metalworking and manufacturing processes, thereby enhancing product quality and sustainability.

Comparison of VT-20 alloy drilling performance evaluation under dry, MQL, EMQL, and hybrid nanoparticle assisted EMQL ecological conditions

The potential of VT-20, a titanium (Ti) alloy in the aircraft industry, is increased as it has stronger thermal capabilities than other pseudo-α-Ti alloys. However, the alloy’s low heat conductivity and chemical reactivity make machining difficult and necessitate efficient cooling/lubrication. Cutting oils based on emulsion have been used to move heat from the cutting region; however, they are not sustainable due to their negative impacts on workers’ health and the environment. Therefore, this novel study investigates alternative lubricating approaches, such as drilling VT-20 alloy under dry, MQL, EMQL, and HNPEMQL conditions using SEM and line-scan EDS analysis. An indigenously developed electrostatic minimum quantity lubrication (EMQL) and hybrid nanoparticles (NPs) immersed in EMQL (HNPEMQL) techniques were utilized to improve drilling performance while reducing cutting oil consumption. Hybrid nanofluids for HNPEMQL application were developed using aluminium oxide (Al2O3) and plate-structured graphene nanoparticles using a two-step process. The surface quality of the drilled hole, tool wear, thrust force, power consumption, hole quality indicators, and microhardness are evaluated. The efficacy of HNPEMQL showed improved drilling efficiency compared to dry, MQL, and EMQL machining. HNPEMQL, EMQL, and MQL conditions reduced tool wear by 102 %, 53 %, and 19 %, respectively, to dry drilling. The HNPEMQL condition lowered the thrust force by 75.3 %, 28.69 %, and 18.02 %, respectively, compared to the dry, MQL, and EMQL. HNPEMQL demonstrated a 105 %, 41 %, and 22 % reduced variation in circularity values than dry, MQL, and EMQL for the same number of drilled holes. The findings show that HNPEMQL can be considered a promising cooling and lubricating strategy with improved drilling performance and quality.

Sustainable machining of Inconel 718 using minimum quantity lubrication: Artificial intelligence-based process modelling

Governments and industries are developing aggressive policies to reduce carbon emissions and shift from fossil fuels to renewable energy. On the other hand, industries struggle to reduce energy consumption and depend on production lot sizes to control energy requirements. In this regard, energy-efficient processing through CNC machine tools can potentially influence energy demand and requires energy-aware power consumption strategies for machining processes. For manufacturing a single product, predicting energy demand can be decisive in determining parametric control and other factors. Previously analytical models have been largely used to model machining requirements and energy demand. However, these models largely depend on parameterization and do not facilitate the integration of external sub-systems. Therefore, in this paper, an artificial intelligence-based power reduction strategy is developed and implemented on single material (Inconel 718), four control parameters (cutting speed, feed rate, depth of cut and flow rate) and two sub-systems (minimum quantity lubrication (MQL) and nanofluids-based minimum quantity lubrication (NF-MQL)). The paper employs four machine learning algorithms,’ K-Nearest Neighbor’, ‘Gaussian Regression’, ‘Decision Tree’, and ‘Logistic Regression’, to evaluate their functionality in predicting power consumption (Pc) of CNC machining systems using a real experimental data set. As per evaluation based on five performance metrics (R-square, MSE, RMSE, MAE, and MedAE), ‘Decision Tree’ has achieved the most accurate power consumption predictions. The comparative results highlight ‘Decision Tree’ as the most better predictor with the optimal max_depth of 2 showing Pc MQL R2 of 0.915 and Pc NF-MQL R2 of 0.931.

In pursuit of sustainability in machining titanium alloys using phosphonium-based halogen-free ionic liquids as potential metalworking fluid additives

In recent years, researchers have investigated ionic liquids (ILs) as suitable metalworking fluids (MWFs) additive. Most commonly used ILs contain halogen anions, which creates issues related to corrosion and toxicity. However, phosphonium-based halogen-free ILs (HF-ILs) provide a safer alternate with enhanced biodegradability and minimal adverse effects on the environment. This research examines the potential of HF-ILs as an additive to canola oil. In this research two halogenated ILs [BMIM][PF6]- and [BMIM][BF4]- and one halogen-free IL ([P6,6,6,14][i(C8)2PO2]-) were added 1 % by volume in canola oil. First, the thermophysical properties of these synthesized MWFs were evaluated. Result concluded that the HF-ILs reduced contact angles on both the workpiece and the cutting tool surfaces by 12– 15 % compared to pure canola oil. Whereas, improved the thermal conductivity by 10.5 %. Furthermore, the machining operation was carried out at two cutting speeds (80 and 100 m/min) and feed (0.1 and 0.2 mm/rev) to analyse the effect of synthesized MWFs under the minimum quantity lubrication method. Findings concluded that phosphonium-based halogen-free IL showed better cutting performance, with reduction in tool wear, cutting temperature by 10–33 %, and surface roughness by 34−46 %. Additionally, this approach supports a "greener" and more sustainable work environment by lowering MWF consumption by using minimal quantity lubrication, reducing tool wear and surface roughness which helps in cost reduction and product rejection for any manufacturing industry.

Internally cooled tools: An eco-friendly approach to wear reduction in AISI 304 stainless steel machining

Austenitic stainless steel 304 is widely used in various applications due to its mechanical strength, toughness, and, most importantly, its corrosion resistance. However, machining this material presents significant challenges, primarily due to its high tendency for work hardening and generation of elevated temperatures. In the cutting process, this temperature rise can result in premature tool wear, leading to a reduction in their lifespan. To address these issues, cutting fluids are typically applied. Although this component offers advantages, it also contributes to environmental pollution, health risks, and significant costs, including disposal.Therefore, this study introduces an Internally Cooled Tool (ICT) method aimed at reducing the heat generated during machining. In this study, an analysis of tool life and wear was conducted to evaluate the effectiveness of ICTs compared to conventional machining methods during the turning of austenitic stainless steel 304 using double-coated tools (AlCrN on TiAlN, PVD (Physical Vapor Deposition)). Additionally, the use of ICTs in combination with lubrication (hybrid machining Minimum Quantity Lubrication (MQL) + ICT) was also investigated. The study covered five machining atmospheres (ICT, ICT + MQL, dry, wet, MQL). Cutting conditions were kept constant, including cutting speed (vc = 400 m/min), feed rate (f = 0.1 mm/rev), and depth of cut (ap = 0.5 mm). Scanning electron microscopy (SEM) analyses were conducted to examine the wear mechanisms and types present in each condition, along with statistical tests such as analysis of variance and Tukey tests to validate the experiments. The results indicated that ICTs (ICT and ICT + MQL) showed a longer tool life compared to dry machining and MQL techniques, while the wet machining method did not demonstrate significance compared to this technique. The observed wear mechanisms included abrasion, adhesion, and diffusion, with abrasion being the predominant mechanism. In summary, it was found that the durability of the inserts was directly related to coating adhesion, as coating detachment quickly led to the end of the insert's lifespan.