Minimum Quantity Lubrication Technique Research Articles

An Experimental Investigation of the Effects MQL Using Nanofluids on Surface Roughness of Hard Milling Process

High cutting force and cutting heat are challenging problems that need to be overcome for the hard milling process. Minimum quantity lubrication (MQL) has been shown to be effective and suitable for use in hard milling due to the improving lubrication in the cutting zone. The content presented in this article is to investigate MQL using emulsion cutting oil with/without Al2O3 nanoparticles for hard milling of 60Si2Mn steel (50-52 HRC) using carbide tools. Factorial experimental design is used to evaluate the cooling condition, cutting speed and feed rate on surface roughness. Experimental results show that feed rate has the greatest influence on surface roughness among the parameters investigated, followed by cooling mode and cutting speed. MQL technique using nano cutting oil gives better machined surface quality than MQL using pure cutting oil, which has proven that the additives of Al2O3 nanoparticles to the base cutting oil has improved cooling and lubrication capability. Furthermore, the applicability of MQL method is expanded to apply for hard milling.

Enhancing machining efficiency of Ti-6Al-4V through multi-axial ultrasonic vibration-assisted machining and hybrid nanofluid minimum quantity lubrication

Ti-6Al-4V offers a balance of good strength with lightweight properties. Yet, Ti-6Al-4V poses machining challenges, including low thermal conductivity, chemical adhesion to cutting tools, and chip removal difficulties. To improve machining efficiency, Ultrasonic Vibration-Assisted Machining (UVAM) has emerged as a promising approach. UVAM has demonstrated reduced tool wear, cutting forces, and improved surface quality compared to Conventional Machining (CM). Additionally, Minimum Quantity Lubrication (MQL) methods offer sustainable coolant alternatives, with recent research focusing on Nanofluid-MQL (NMQL) and Hybrid Nanofluid-MQL (HNMQL) for enhanced performance. Although there exists a body of literature showcasing the promising effects of UVAM and MQL methods individually, comprehensive investigations into the synergistic effects of these methodologies remain limited. This study addresses these critical research gaps by conducting a systematic examination of combined application of multi-axial UVAM and HNMQL. Specifically, it delves into the comparison of different vibration directions within UVAM, evaluates the effectiveness of UVAM when combined with cutting fluids incorporating Al2O3 and CuO nanoparticles in NMQLs and HNMQLs, and contrasts these novel approaches with conventional machining methods. The study unfolds in three distinct stages. The first stage examines the ultrasonic cutting mechanism and its combined application with the MQL technique. In the second stage, the study investigates the physical properties of the cutting fluids, including contact angle and surface tension. The final stage encompasses slot milling operations, where an array of parameters such as cutting forces, surface roughness, surface topography, surface texture, and the occurrence of burr formations are rigorously analyzed. The results demonstrate that the combination of multi-axial UVAM with HNMQL yields substantial advantages over traditional machining methods. Notably, it leads to a remarkable reduction in cutting forces (up to 37.6 %) and surface roughness (up to 37.4 %). Additionally, this combination engenders the production of highly homogeneous and uniform surface textures, characterized by minimal surface defects and a significantly diminished occurrence of burr formations. These findings underscore the potential of multi-axial UVAM combined with HNMQL as a promising approach in enhancing the machining of Ti-6Al-4V, thus offering a pathway to enhance the efficiency and precision of aerospace component manufacturing processes.

Minimum Quantity Lubrication (MQL) Supply through Internal Cooling Channels in Drilling Processes

Minimum quantity lubrication (MQL) technologies possess great potential for improving the sustainability of manufacturing processes, which can reduce the absolute quantity of metalworking fluid (MWF) and also enable near-dry chips that are easier to recycle. During drilling in particular, the MWF is transported to the contact zone through internal cooling channels of the drilling tool. The MWF supply and its associated flow behaviour in the transfer from the outlet of the cooling channels to the contact zone have not been sufficiently investigated yet. Great potential is seen in the proper delivery of the MQL into the contact zone. This work aims to visualize and quantify the cooling lubricant supply into the cutting zone using the MQL technique. The visualization of the MQL application is made possible by high-speed shadowgraphic imaging. Detailed image processing is used to evaluate the resulting images. The developed evaluation routine allows for the assessment of the impact of the main process parameters such as the varying pressure of the aerosol generator and the cooling channel diameter. It is found that the oil leaves the cooling channels at the tip of the drill bit in the form of ligaments. An increase in pressure and cooling channel diameter leads to an increase in the frequency of oil ligament separation. Three main flow regimes are identified with different separation frequencies. Low inlet pressures result in intermittently dispersed droplets. The most upper pressure levels lead to an almost continuous dispersion of the oil. At the same time, the air and oil mass flow rates also increase.

Effect of Minimum Quantity of Lubricant on Carbide Tools and Surface Integrity in the Machining of Titanium Aluminides

Titanium aluminides are being explored as potential materials for the aeronautical sector. However, their application is limited by the high costs of processing and their difficulties in machining. This research evaluates the effectiveness of the minimum quantity lubrication technique (MQL) on the turning process of Ti48Al2Cr2Nb aluminide in terms of tool wear, tool life, cutting forces, surface integrity, and temperature. It was found that MQL conditions can improve the process efficiency, reducing the thermally induced wear mechanisms and enlarging the tool life compared to dry machining. Furthermore, it allows the cutting speed to be incremented, leading to lower processing times. However, MQL seems to not be effective in the reduction of the strain-hardening effect near the machined surface and, although the number of microcracks is reduced, defect-free surfaces cannot be obtained. Moreover, similar microstructural alterations as for dry cutting were detected. The best cutting conditions in terms of surface quality were assessed using the central composite face (CCF) design and surface response methodology. Optimization of the surface roughness under industrially viable cutting conditions was achieved with an average surface roughness value, Ra, of 0.29 µm (feed rate of 0.05 mm/rev, a cutting speed of 54.6 m/min and a depth of cut of 0.125 mm).

Experimental investigations on the performance of ductile cast iron with palm oil during turning process using MQL technique

This project focuses on turning of ductile cast iron using the MQL (Minimum Quantity Lubrication) technique. Vegetable oil is used as a substitute cutting fluid, and the results are compared with dry conditions to demonstrate the benefits of turning the material under MQL environment. Three process parameters, namely cuttingspeed (V), feed (F), and depth of cut (D), are varied to obtain the responses like cutting force (Fc) and surface roughness (Ra). In wet turning edible vegetable palm oil is misted onto the tool-workpiece contact. The cutting force and surface roughness are tabulated for both dry and wet machining. Based on these data, Taguchi optimization is performed using L27 design for both wet and dry conditions. The optimization of the process parameters is done for both dry and wet turning. There is a significant difference with respect to cutting force and surface roughness is appreciated to demonstrate the effectiveness of MQL turning over dry turning of ductile cast iron. The cutting force during wet turning is reduced, from 5.89 kgf to 4.91 kgf and surface roughness is reduced from 0.832 µm to 0.629 µm compared with dry turning. The optimized parameters are included in the conclusion of this paper.

Economic analysis of eco-friendly lubrication strategies for the machining of Ti48Al2Cr2Nb aluminide

Titanium aluminides have been identified as potential materials in the aeronautical sector. However, the high processing costs and their low machinability limit their application. This research evaluates the effectiveness of minimum quantity lubrication technique (MQL) and cryogenic lubrication on the turning process of Ti48Al2Cr2Nb aluminide from an economic and industrial productivity point of view, with the aim of determining the optimum cutting conditions to reduce manufacturing costs and maximize the production rate. To this end, a preliminary experimental analysis will be carried out, determining the tool life as a function of the cutting speed for each lubrication condition (dry, MQL and LN2). The results show that, although both MQL and LN2 conditions allow the tool wear to be reduced, the MQL technique stands out for its higher efficiency and for the possibility of reaching a higher cutting speed. In addition, the high cost of liquid nitrogen implies a 47% additional cost. Consequently, this research finds out that the turning process should be carried out in the cutting speed range of 70–76 m/min under MQL conditions to obtain the highest profit rate.

Evaluation of palm kernel oil as lubricants in cylindrical turning of AISI 304 austenitic stainless steel using Taguchi-grey relational methodology

The disadvantages of the conventional cutting fluids such as mineral oil have prompted the search for eco-friendly cutting fluids. Vegetable oils have often been recommended as environmentally friendly substitutes for traditional mineral oil. The current study examined the performance of palm kernel oil (PKO) and its mineral oil during the turning of AISI 304 steel using the minimum quantity lubrication (MQL) technique. Six litres of crude PKO were extracted from palm kernel seeds through a mechanical extraction technique. Taguchi L9 (3)3 orthogonal array was considered for the experiment. The depth of cut (DC), feed rate (FR), and spindle speed (SS) are the cutting parameters while cutting temperature (CT) and surface roughness (SR) are the response characteristics. Experimental results showed that the mineral oil outperformed the PKO in terms of SR with an improvement of 48.2%. The improvement of PKO over mineral oil is approximately 0.89% in terms of cutting temperature. The highest turning temperature of mineral oil was 67.333 °C, while that of PKO was 67.8 °C. In general, the performance of PKO shows it can be a good replacement for mineral oil if produced industrially with adequate additives. The grey relational analysis (GRA) showed that the optimum DC, FR, and SS for palm kernel and mineral oils are 1.25 mm, 0.25 mm rev−1 and 870 rev min−1, and 1.25 mm, 0.10 mm rev−1, and 870 rev min−1, respectively. The results of this study demonstrated an experimental basis for the application of PKO minimal quantity lubrication turning and validated the efficacy of the integrated Taguchi-grey relational analysis (TGRA) optimization approach.

Performance assessment of vegetable-based additive enriched cutting fluid for eco-friendly machining environment.

The investigation focuses on determining the effects of canola oil-based cutting fluid with three different volume percentages of boric acid additives over the machining forces and surface roughness while turning hardened AISI 1018 mild steel. Experiments were carried out under Taguchi's design of the experiment concept. The minimum quantity lubrication (MQL) technique was followed to minimize the cutting fluid consumption. The homogeneity of the additives dispersed in the fluid has been validated through a zeta potential study. Machining forces and surface roughness were considered as chief machining objectives. The hybrid mathematical model, grey relational analysis (GRA)-artificial neural network (ANN), has been implemented to assess the performance of developed cutting fluid. The results explored that the canola oil cutting fluid with 5 wt% of boric acid additive exhibits lesser cutting forces and surface roughness. The optimal machining parameters identified by the hybrid modeling are 665rpm of cutting speed, 35mm/min of feed rate, and 0.3mm of depth of cut, along with 5 wt% of boric acid composition in cutting fluid. The results explore the 2.677 times improvement in machining objective in comparison with a non-optimal set of parameters. The implementation of hybrid modeling is considered to be a novel attempt to minimize the machining objectives. It has been recorded a negligible error percentage of 0.66% between GRA and ANN prediction.

An Experimental Investigation of the Effects of Dressing and Grinding Parameters on Sustainable Grinding of Inconel 738 Used for Automated Manufacturing

The significant effect of the dressing process on the surface of the grinding wheel (GW) and the need to provide an optimal dressing condition are the requirements of reduction machining time and energy consumption in the sustainable grinding process. In this study, for the first time, the results of changes in the parameters of the dressing process and changes in the topography of the grinding surface on the surface roughness of the Inconel 738 have been presented using single-edge and four-edge diamond dressers. The use of minimum quantity lubrication (MQL) and wet condition are other variables in this study to reduce the consumption of cutting fluid and prevent its destructive effects on the environment. The results indicate that the MQL technique increases the grinding performance of Inconel 738 by reducing ground workpiece surface roughness and decreasing the coolant–lubricant consumption comparing to the conventional wet grinding process. Additionally, it has been found from the experimental results that applying a single-edge dresser generates finer topography on the grinding wheel and, consequently, has a better surface finish in the grinding process compared to the multipoint diamond dressing tool with the same dressing and grinding parameters. In other words, increasing the dressing feed rate during dressing of the grinding wheel using a multipoint dresser makes a finer wheel surface topography and as a result decreases the surface roughness of the ground workpiece compared to a single-edge dresser. With multipoint diamond tools, the grinding performance during the life of the dressing tool also tends to remain more consistent, which is a definite advantage in automated production. Therefore, application of a multipoint dresser leads to a reduction in dressing time and increased production capability.

A review on minimum quantity lubrication (MQL) assisted machining processes using mono and hybrid nanofluids

PurposeBecause many cutting fluids contain hazardous chemical constituents, industries and researchers are looking for alternative methods to reduce the consumption of cutting fluids in machining operations due to growing awareness of ecological and health issues, government strict environmental regulations and economic pressures. Therefore, the purpose of this study is to raise awareness of the minimum quantity lubrication (MQL) technique as a potential substitute for environmental restricted wet (flooded) machining situations.Design/methodology/approachThe methodology adopted for conducting a review in this study includes four sections: establishment of MQL technique and review of MQL machining performance comparison with dry and wet (flooded) environments; analysis of the past literature to examine MQL turning performance under mono nanofluids (M-NF); MQL turning performance evaluation under hybrid nanofluids (H-NF); and MQL milling, drilling and grinding performance assessment under M-NF and H-NF.FindingsFrom the extensive review, it has been found that MQL results in lower cutting zone temperature, reduction in cutting forces, enhanced tool life and better machined surface quality compared to dry and wet cutting conditions. Also, MQL under H-NF discloses notably improved tribo-performance due to the synergistic effect caused by the physical encapsulation of spherical nanoparticles between the nanosheets of lamellar structured nanoparticles when compared with M-NF. The findings of this study recommend that MQL with nanofluids can replace dry and flood lubrication conditions for superior machining performance.Practical implicationsMachining under the MQL regime provides a dry, clean, healthy and pollution-free working area, thereby resulting the machining of materials green and environmentally friendly.Originality/valueThis paper describes the suitability of MQL for different machining operations using M-NF and H-NF.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2023-0131/

EFFECTS OF VIBRATION CONDITIONS ON MACHINABILITY OF AISI 52100 BEARING STEEL

This study focused on determining the effects of the cooling condition in the conventional and ultrasonic-assisted turning of AISI 52100 steel. AISI 52100 steel has been widely used in the bearing, mold, and automotive industries because of its superior wear resistance and mechanical properties. However, its high wear resistance caused poor machinability in conventional machining methods. Low surface quality, rapid tool wear, high cutting temperature, and high cutting force are the main difficulties in the conventional machining of AISI 52100 steel. On the other hand, ultrasonic-assisted machining has become widely used in the past decades for the machining of materials that have low machinability in conventional methods. Conventional turning and ultrasonic-assisted turning were selected as machining methods. Ultrasonic-assisted turning experiments were conducted under 20 and 30 kHz vibration frequencies. Cubic Boron Nitride (CBN) cutting tools were used in machining experiments. In machining operations 50, 100, and 150 m/min cutting speeds were selected, and feed rate (0.1 mm/rev) and depth of cut (0.5 mm) were kept constant in experiments. Minimum quantity lubrication technique which used 1% Al2O3 nanoparticle additives cutting fluid and dry cooling methods were used. CBN insert was used as a cutting tool. The effects of cutting speed, cutting method, and cooling condition on surface quality, cutting force, cutting zone temperature, and cutting tool wear were studied experimentally. Analysis of Variance (ANOVA) was carried out to determine the significance of the effects of input variables on process outputs. As a result of this study, it is determined that combined UAT and nanoMQL have significant effects on the process outputs.

Dry machining of alloy steels – A review

Dry machining has been used as an alternative method in place of the conventional machining process as the usage of cutting fluid has many side effects and adds more cost to the manufacturing process. Handling and recycling of chips is the main feature of the dry machining process. The heat generated and the tool life are the major concerns in dry machining. There is an alternative method called the minimum quantity lubrication technique where the cutting fluid is sprayed in the form of a mist. Alloy steels are extensively used for the manufacturing of various components in automobile, aircraft, military, and medical industries. It’s crucial to study the dry machining of alloy steels to achieve high-quality finished products at economical costs. In turning operation cutting speed, feed rate, depth of cut and cutting environment are the controllable machining parameters which affect the outputs like surface roughness, tool wear, tool life, MRR, power consumption, etc. In practice when machining is done there are some desired characteristics for the output parameters, that can’t be achieved with some random input parameters combination, the combination of input parameters where desired characteristic of output parameters is achieved is called optimal parameter condition. Optimal conditions for the machining process can be found using the Taguchi technique based on means method or S/N ratio method and ANOVA is used to find the significance of input dimension on outputs. This optimal condition can be found for each individual output parameter or else for all output parameters at once which is called multi-objective optimization. Machine learning model can be developed using experimental data for prediction. The model will be trained based on the training data that has been provided to it. Machine learning models can avoid the waste of time of manual experimentation and directly predict the values.

Machinability investigation of Ti-6Al-4V titanium alloy under dry, flood, MQL and nanofluid-MQL techniques using textured tools

ABSTRACT While machining titanium alloys, using metalworking fluids (MWFs) helps improve the tribological properties. However, its usage is restricted considering the harmful effects on health and the environment under sustainable machining. Using minimum quantity lubrication (MQL) to improve machining performance without utilising an excessive amount of cutting fluid is becoming more prevalent. Pure-MQL, however, might not be adequate for machining titanium alloys. Due to their improved heat transfer capabilities, nanofluid-based lubricants are extremely popular for use in the machining of superalloys. In this direction, the efficacy of the MQL mixture can be improved by using vegetable-oil-based cutting fluid reinforced with nanoparticles. Therefore, this study compares dry, flood, MQL and nanofluid-MQL techniques while machining Ti-6Al-4V titanium alloy with textured tools. The Hexagonal Boron Nitride (hBN) nanoparticles are added to the base fluid to develop a nanofluid-MQL mixture. Machinability indicators are analysed, namely tool wear, surface roughness, power consumption, and specific cutting energy. The outcomes showcased the efficacy of nanofluid-MQL with lower surface roughness, tool wear, and specific energy requirements compared to other conditions. It is observed that combining vegetable oil and hBN nanoparticles in nanofluid-MQL reduced friction and improved cooling in the machining interfaces.

A review on minimum quantity lubrication technique application and challenges in grinding process using environment-friendly nanofluids

A review on minimum quantity lubrication technique application and challenges in grinding process using environment-friendly nanofluids

A novel cold air electrostatic minimum quantity lubrication (CAEMQL) technique for the machining of titanium alloys Ti–6Al–4 V

A novel cold air electrostatic minimum quantity lubrication (CAEMQL) technique for the machining of titanium alloys Ti–6Al–4 V

Sustainable Machining: MQL Technique Combined with the Vortex Tube Cooling When Turning Martensitic Stainless Steel X20Cr13

For the purpose of contributing to sustainable machining, the aim was to investigate the turning of martensitic stainless steel X20Cr13 under alternative cooling and lubrication techniques. The minimum quantity lubrication technique in combination with the vortex tube cooling, as the determined optimal cooling method using the Taguchi-based entropy weighted grey relational analysis (compared to emulsion and minimum quantity lubrication technique) in previous research when turning martensitic stainless steel X20Cr13, were applied in this research in accordance with the Box–Behnken design. The aim is to investigate, when applying the optimal cooling condition (minimum quantity lubrication + vortex) with the Box–Behnken design, which parameters have a significant influence on reducing the surface roughness parameters Ra and Rz and also on the tool life (T). The cutting speed (vc = 260, 290 and 320 m/min), feed rate (f = 0.3, 0.35 and 0.4 mm/rev) and depth of cut (ap = 1, 1.5 and 2 mm) were selected as cutting parameters. An exponential model for Ra, Rz and T was obtained. According to the ANOVA results, it can be seen that only the feed rate had a significant influence on Ra and Rz. For tool life, according to the ANOVA results, it can be seen that all three parameters (cutting speed, feed rate and depth of cut) have significant influence on the tool life (T). Experimental results were compared with the results of the exponential mathematical model and presented in diagrams. A new nozzle was designed for this research to allow micro-droplets from the MQL unit and chilled compressed air from the vortex tube to be connected in one stream (single-channel system) before entering the cutting zone, thus allowing for simultaneous lubrication and cooling. For the used vortex tube system with an air flow of 708 L/min and the inlet air pressure of 0.69 MPa, a temperature drop of −29 °C can be achieved in regard to the inlet air temperature of 21 °C. Therefore, the minimum quantity lubrication technique with vortex tube cooling can be recommended for turning of martensitic stainless steel X20Cr13.

Tribological mechanism of carbon group nanofluids on grinding interface under minimum quantity lubrication based on molecular dynamic simulation

Carbon group nanofluids can further improve the friction-reducing and anti-wear properties of minimum quantity lubrication (MQL). However, the formation mechanism of lubrication films generated by carbon group nanofluids on MQL grinding interfaces is not fully revealed due to lack of sufficient evidence. Here, molecular dynamic simulations for the abrasive grain/workpiece interface were conducted under nanofluid MQL, MQL, and dry grinding conditions. Three kinds of carbon group nanoparticles, i.e., nanodiamond (ND), carbon nanotube (CNT), and graphene nanosheet (GN), were taken as representative specimens. The [BMIM]BF4 ionic liquid was used as base fluid. The materials used as workpiece and abrasive grain were the single-crystal Ni-Fe-Cr series of Ni-based alloy and single-crystal cubic boron nitride (CBN), respectively. Tangential grinding force was used to evaluate the lubrication performance under the grinding conditions. The abrasive grain/workpiece contact states under the different grinding conditions were compared to reveal the formation mechanism of the lubrication film. Investigations showed the formation of a boundary lubrication film on the abrasive grain/workpiece interface under the MQL condition, with the ionic liquid molecules absorbing in the groove-like fractures on the grain wear’s flat face. The boundary lubrication film underwent a friction-reducing effect by reducing the abrasive grain/workpiece contact area. Under the nanofluid MQL condition, the carbon group nanoparticles further enhanced the tribological performance of the MQL technique that had benefited from their corresponding tribological behaviors on the abrasive grain/workpiece interface. The behaviors involved the rolling effect of ND, the rolling and sliding effects of CNT, and the interlayer shear effect of GN. Compared with the findings under the MQL condition, the tangential grinding forces could be further reduced by 8.5%, 12.0%, and 14.1% under the diamond, CNT, and graphene nanofluid MQL conditions, respectively.

A Study on the Effects of Hybridized Metal Oxide and Carbonaceous Nano-Cutting Fluids in the End Milling of AA6082 Aluminum Alloy

Finding an alternate solution for supplanting the existing conventional lubricant in machining is a challenge. This work narrows the search down to the use of nano-cutting fluids, as they exhibit excellent properties such as high thermal conductivity and good lubricity. A technical analysis of the performance of hybrid nano-cutting fluids in the end milling of AA6082 aluminium alloy in a constrained end milling condition is presented. Alumina and carbon nanotubes were chosen in this study for their better physical characteristics and compatibility during machining. Coconut oil was chosen as the base fluid (dispersal medium) as it provides good lubricity and better dispersion of nanoparticles due to its excellent rheological behaviour. The hybrid nanofluid was prepared by mixing alumina-based nanofluid with carbon nanotube nanoparticles in different volumetric concentrations. The thermo-physical properties of the prepared hybrid nanofluid were tested. Furthermore, they were tested for their spread-ability and other mechanical properties. Later, their performances as cutting fluid were studied with the minimum quantity lubrication (MQL) technique, wherein nanoparticle mist was formed and evaluated in the end milling of AA6082 aluminium to reduce the quantity of nanofluids’ usage during end milling. The controllable parameters of speed, feed rate, and type of cutting fluid were chosen, with the levels of cutting speeds and feed rate at 75–125 m/min, and 0.005–0.015 mm/tooth, respectively, and the response parameters studied were surface roughness and tool wear. The results show that better performance is achieved in hybridized nano-cutting fluid, with a sharp improvement of 20%, and 25% in tool wear and surface roughness when compared to the base fluid. This study has explored the concept of hybridization and the capability of nanofluids as cutting fluids that can be used as eco-friendly cutting fluids in manufacturing industries.

State-of-the-Art in Sustainable Machining of Different Materials Using Nano Minimum Quality Lubrication (NMQL)

In the manufacturing industry, during machining, the conventional cutting fluid plays a vital role; however, extravagant use of cutting fluids due to its disposal affects the environment badly. Nowadays, due to these advantages of conventional cutting fluids, alternative methods of conventional cutting fluids or alternative methods are preferred. One of the most preferred methods may be the minimum quantity lubrication technique with conventional or nanoparticle-enriched cutting fluids. The present paper has a compilation of the investigations based on MQL application in different machining processes such as turning, milling, grinding, and drilling. The machining also involves hard-to-machine alloys. The paper discusses cryogenic MQL in brief and opens the domain for work in future. The purpose of this paper is to provide a quick reference for researchers working on the practical use of MQL lubricants with nanopowders dissolved and their application in machining for different materials.

Influence of nano-minimum quantity lubrication with MoS2 and CuO nanoparticles on cutting forces and surface roughness during grinding of AISI D2 steel

Environmental side effects of machining lubricants are the main reasons for the progressive development of utilizing the minimum quantity lubrication (MQL) method instead of conventional methods. Owing to the high specific energy of cutting and generation of more heat in grinding, the MQL technique has a lower efficiency than conventional methods. However, by adding nanoparticles to the base oil, the lubrication efficiency in grinding can be enhanced. In this research, grinding of cold work tool steel AISI D2 was studied using a MQL technique by adding MoS2 and CuO nanoparticles to two types of vegetable-based oils: colza and soybean with different concentration percentages, and their effects were examined on the cutting forces (normal and tangential forces) and surface roughness. The results indicated that the values of normal force and tangential forces diminished by 19 and 35 % when using CuO nano powder in soybean base oil with a concentration of 4 % and MoS2 nano powder in soybean base oil with a concentration of 2 %, respectively. Furthermore, when using CuO nano powder in colza base oil and with a concentration of 2 %, the surface roughness had a significant reduction of 77 % in comparison with pure oil as a grinding fluid.