Minimum Quantity Lubrication Method Research Articles

Study on Tool Deterioration in Machining with Minimum Quantity Lubrication (MQL) Condition

This study aims to observe the tool deterioration following application of minimum quantity lubrication method (MQL). The designed MQL system is completed with an Arduino controller system which was able to be either manually-controlled or automatically-controlled. The tool used in this study is DCMT 11 insert type. The Taguchi method using the Orthogonal Array L9 design was used to compile the design of experiments with variations in depth of cut, coolant composition, and cooling fluid application methods. Each variable consists of three levels. Tool deterioration evaluated by observing it under an optic microscope from three sides of the tool. There are four levels of tool deterioration. The value of tool deterioration of each tool is the accumulation of each side view. ANOVA analysis found that depth of cut, cutting tool composition and method of applying coolant influence tool deterioration in percentage by 32.69%, 17.30 % and 12.82% respectively. Moreover, the minimum tool deterioration would be achieved when using the parameter combination of depth of cut of 1.6 mm; mixture composition of 3:7; and using the temperature-controlled MQL.

Cutting tool wear in turning 316L stainless steel in the conditions of minimized lubrication

316L stainless steel has emerged as one of the most used material in design and manufacturing for automotive, aerospace, marine, civil nuclear to produce critical components (valves, seats, pipes etc.). Despite, their huge application, during the machining of 316L stainless steel numerous challenges arise in terms of tool wear that are very detrimental for the surface of machined part. To obtain an extended life of tool used for machining commonly 316L stainless steel two different methods of cooling based on minimum lubrication condition, namely Minimum Quantity Lubrication (MQL) method and Minimum Quantity Cooling Lubrication (MQCL) with the addition of extreme pressure and anti-wear (EP/AW) method, respectively were settled. The use of the MQL method resulted in a reduction of the cutting tool wear by approximately 9% compared to the MQCL + EP/AW method and by approximately 21% compared to dry machining. Further, the highest values of wear indices were achieved during dry machining and the lowest ones in the method of minimized lubrication which validate the minimum lubrication as beneficial for reducing the wear progress.

Quality in turning of Inconel X-750 superalloy

This study has been conducted to analyse the effects of turning the Inconel X-750 superalloy, which is a member of a nickel-based superalloy family that is frequently preferred in the aerospace and nuclear energy industries in particular, under minimum quantity lubrication (MQL), cryogenic liquid nitrogen (LN2) and carbon dioxide gas (CO2) cooling/lubrication conditions, with different cutting speeds (V c = 65, 95, 125 and 155 m/min) and constant feed rate (f = 0.1 mm/revolution) and cutting depth (a = 0.5 mm) parameters, on the processability of Inconel X-750, hence on the surface integrity. In this context, the results obtained from the tests have been comparatively examined through surface roughness, tool wear and chip formation. Comparison results show that the cryogenic carbon dioxide method has generally provided the best surface roughness and tool wear values. The MQL method has provided the best chip formation.

An Experimental Investigation on Thermal Conductivity and Viscosity of Graphene doped CNTs /TiO2 Nanofluid

This paper presents the findings of the stability, thermal conductivity and viscosity of CNTs (doped with 10 wt% graphene)- TiO2 hybrid nanofluids under various concentrations. While the usage of cutting fluid in machining operation is necessary for removing the heat generated at the cutting zone, the excessive use of it could lead to environmental and health issue to the operators. Therefore, the minimum quantity lubrication (MQL) to replace the conventional flooding was introduced. The MQL method minimises the usage of cutting fluid as a step to achieve a cleaner environment and sustainable machining. However, the low thermal conductivity of the base fluid in the MQL system caused the insufficient removal of heat generated in the cutting zone. Addition of nanoparticles to the base fluid was then introduced to enhance the performance of cutting fluids. The ethylene glycol used as the base fluid, titanium dioxide (TiO2) and carbon nanotubes (CNTs) nanoparticle mixed to produce nanofluids with concentrations of 0.02 to 0.1 wt.% with an interval of 0.02 wt%. The mixing ratio of TiO2: CNTs was 90:10 and ratio of SDBS (surfactant): CNTs was 10:1. The stability of nanofluid checked using observation method and zeta potential analysis. The thermal conductivity and viscosity of suspension were measured at a temperature range between 30˚C to 70˚C (with increment of 10˚C) to determine the relationship between concentration and temperature on nanofluid’s thermal physical properties. Based on the results obtained, zeta potential value for nanofluid range from -50 to -70 mV indicates a good stability of the suspension. Thermal conductivity of nanofluid increases as an increase of temperature and enhancement ratio is within the range of 1.51 to 4.53 compared to the base fluid. Meanwhile, the viscosity of nanofluid shows decrements with an increase of the temperature remarks significant advantage in pumping power. The developed nanofluid in this study found to be stable with enhanced thermal conductivity and decrease in viscosity, which at once make it possible to be use as nanolubricant in machining operation.

A Study of Chip Formation on Turning with Minimum Quantity Lubrication Method (MQL)

The cutting fluid is one of the essential factors in machining to increase machinability. The issuance of ISO 14000 about reducing the use of cutting fluid for its danger for operator and environment has encouraged many researchers to find ways to minimize its use. The Minimum Quantity Lubrication (MQL) is an answer to it. To further reduce the use of cutting fluid, a device that complies with MQL criteria for controlling the spray based on the tool temperature has successfully designed. This paper is discussing the effect of applying this device to the chips formation. The experiments were on turning of AISI 4340 using carbide tools. The Taguchi method L9 used to design the experiments. The variations made on the method of applying the cutting fluid, depth of cut, and cutting fluid composition. The chips formation was calculated based on the value of the degree of serration. Analysis of the S/N ratio, followed by ANOVA, revealed that the cutting fluids application method is the least factor affecting the chips formation. In contrast, the depth of cut influences the chips formation by 75 per cent more. The highest degree of serration achieved when applying the combination of depth of cut of 1.8 mm, the composition of 5:5, and flood method of applying cutting fluid.

Experimental Studies on the Centrifugal MQL-CCA Method of Applying Coolant during the Internal Cylindrical Grinding Process.

This paper presents the results of experimental research concerning the possibility of supporting the cooling function during internal cylindrical grinding using the minimum quantity lubrication (MQL) method by additional delivery of a compressed cooled air (CCL) stream. The article presents a description of a hybrid method of cooling and lubrication of the grinding zone integrating centrifugal (through a grinding wheel) lubrication with the minimum quantity of lubricant and cooling with a compressed cooled air stream generated by a cold air gun (CAG). The methodology and results of experimental studies are also presented in detail, with the aim of determining the influence of the application of the hybrid method of cooling and lubrication of the machining zone on the course and results of the internal cylindrical grinding process of 100Cr6 steel in comparison with other methods of cooling and lubrication, as well as compared with dry grinding. The research results obtained using the described hybrid method of cooling and lubrication of the grinding zone are related to the results obtained under the conditions of centrifugal MQL method, cooling with a stream of CCA, cooling and lubrication with a stream of oil-in-water emulsion delivered using the flood method, and dry grinding. The efficiency of the grinding process is evaluated (based on the average grinding power Pav, grinding wheel volumetric wear Vs, material removal Vw, and grinding ratio G), along with the thermal conditions of the process (based on the analysis of thermograms recorded by infrared thermal imaging method), the textures of machined surfaces (based on microtopography measured by contact profilometry), the state of residual stress in the surface layers of workpieces (determined by X-ray diffraction method), and the state of the grinding wheels’ active surfaces after grinding (based on microtopography measured by laser triangulation and images recorded with a digital measuring microscope). The obtained results of the analyses show that the application of the hybrid method allows for the longest wheel life among the five compared grinding methods, which is about 2.7 times the life of grinding wheels working under the flood cooling and centrifugal MQL methods, and as much as 8 times the life of grinding wheels working under the conditions of CCA only and dry grinding.

Rancang Bangun dan Uji Performa Sistem Kendali Pemberian Fluida Permesinan MQL Berbasis Arduino

In machining excessive use of cutting fluid can have a negative impact to the enviroment. An alternative to overcome this problem is by using the minimum quantity lubrication method (MQL). In MQL method the cutting fluid is flowed by compressed air. This research aim to design and implement an Arduino-based controller for further minimize the use of cutting fluid in MQL system. It was programmed that the pump would only work when the tool temperature beyond 70 oC and vice versa. Observation shows that the controller work accordingly. Other experiments were carried out to check the fluid consumption with Taguchi method. It was proof that applying the controller was able to reduce the fluid consumption.

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.

Effects of Minimum Quantity Lubrication (MQL) on cutting temperature, tool wear and surface roughness in turning AISI-1045 material

The effects of cutting fluids to health, environment, productivity, and quality in machining operations have been discussed. MQL is a green technology that is gradually applied in mechanical processing. The article has introduced about MQL cooling lubrication method in mechanical processing. Some previous research results have been made to clarify the meaning of this method. In addition, the comparison of the outputs of MQL, dry, and wet methods has also been shown to show the effectiveness of the MQL method. Then, based on the MQL equipment being used at Tran Dai Nghia University, the authors designed the experiment to evaluate the impact of MQL parameters on the process outputs. Machining and optimization of that parameter. This paper presents the MQL parameters optimization approach in which the multi-response outputs based on Taguchi's L9 orthogonal array method is used. During the turning AISI-1045 steel, the cutting temperature, the maximum of tool wear, and the surface roughness were measured. The MQL parameters, which are the ratio of soluble lubricant and water, pressure of spray head, the flow volume of the emulsion was simultaneously optimized by taking the multi-response outputs using Taguchi based grey relational analysis (GRA) into consideration. In turning experiments, three different flow volume of emulsion Q (40, 60, 80 ml/h), three different levels pressure of spray head P (3, 5, 7 bar) and three different levels ratio of soluble lubricant and water R (4, 6, 8%) were used. Here, three mathematical models were created using response surface regression methodology. The experiments had been done to investigate the effect of the MQL parameters to the turning process. As a result, the set of optimal MQL parameters had been pointed out to simultaneously minimize the cutting temperature, the tool wear, and surface roughness. The Flow volume of emulsion 80 ml/h, Pressure of spray head 7 bar, Ratio of soluble lubricant, and water 6% was observed to be the most effective.

Evaluation of turning with different cooling-lubricating techniques in terms of surface integrity and tribologic properties

This research presents the analysis of metrologic and tribologic aspects of machined surfaces obtained after turning with the application of various cooling/lubricating methods. The thoroughly conducted machining tests are: dry machining, minimum quantity cooling lubrication (MQCL); minimum quantity cooling lubrication with EP/AW modifications (MQCL+EP/AW) and minimum quantity lubrication (MQL). The phosphate ester based modification in the MQCL+EP/AW method is employed in order to increase the lubricating properties of the emulsion. The surface topography, responsible for the tribological properties of mating parts, is measured. The smallest values of the surface roughness are obtained after turning under MQCL+EP/AW conditions, while the highest values of parameters responsible for oil retention in mating parts are obtained after machining with the MQL method.

Grinding hardened steel using MQL associated with cleaning system and cBN wheel

The minimum quantity lubrication (MQL) is one of the most promising alternative techniques to replace the conventional application of cutting fluids. However, its use in grinding is still a challenge, as overheating and wheel clogging occur, leading to workpiece quality worsening. This work investigates a wheel cleaning jet associated with the MQL (MQL+WCJ) at three flow rates in grinding of AISI 4340 hardened steel with a cBN wheel, comparing the results with MQL and conventional methods. The output parameters assessed were workpiece surface roughness, roundness deviation, and microhardness, diametrical wheel wear, acoustic emission, and grinding power, and the machined surfaces were analyzed through microscopy techniques (optical, scanning electron, and confocal). The MQL+WCJ outperformed MQL in all the tested conditions. The application of the wheel cleaning jet reduced by up to 73% the wheel wear, 69% the surface roughness, 45% the roundness deviation, 60% the acoustic emission, and 24% the grinding power, regarding MQL without wheel cleaning, contributing to a more environmentally friendly and efficient grinding.

Slot milling of titanium alloy with hexagonal boron nitride and minimum quantity lubrication and multi-objective process optimization for energy efficiency

The implementation of sustainable manufacturing techniques to make machining processes more eco-friendly is a challenging topic that has attracted significant attention from the industrial sector for many years. As one of the dominant manufacturing processes, machining can have a considerable impact in terms of ecology, society, and economics. In certain areas, this impact is a result of using certain cutting fluids, especially during the machining of difficult-to-cut alloys such as titanium, where a large amount of cutting fluid is wasted to ease the cutting process. In such scenarios, identifying suitable machining conditions to supply cutting fluids using eco-friendly techniques is currently a major focus of academic and industrial sector research. In this study, effects of minimum quantity lubrication with different concentrations of hexagonal boron nitride nanoparticles on the surface roughness and cutting force of slot-milled titanium alloy is investigated using analysis of variance and response surface methodology. The results reveal that all responses are sensitive to changes in the feed per tooth, cutting depth, and cutting fluid flow rate. The regression functions generated were combined with particle swarm optimization in order to improve energy-efficiency, as well. Possible sectorial scenarios were generated for wider industrial adoption. With this study, it was proven that utilizing minimum quantity lubrication with hexagonal boron nitride nanoparticles can reduce both cutting force and surface roughness, which makes it to be a promising alternative as a nanoparticle augmented minimum quantity lubrication method for machining titanium alloys.

Grinding performance of bearing steel using MQL under different dilutions and wheel cleaning for green manufacture

Cutting fluids have a fundamental role in machining, especially in grinding, since they are responsible for lubrication and refrigeration of the cutting region. On the other hand, they may cause damage to the environment and to the health of the operators. Thermal damage, geometric inaccuracies and degradation of the surface integrity of the workpiece are diminished with the use of cutting fluids. While in the conventional application of cutting fluid a large amount of oil or emulsion of oil with water is used, in the minimum quantity lubrication (MQL) technique a small amount of oil is applied via a jet of compressed air reaching, in many cases, results comparable to the conventional method. However, the lower cooling capacity of MQL and the clogging of the wheel pores caused by the hot chips are obstacles to be overcome. This work evaluates the addition of water to the MQL method in the external cylindrical plunge grinding of AISI 52100 steel to improve the deficiencies of this technique. The results analyzed include surface roughness (Ra), workpiece surface damages, roundness deviation, grinding wheel wear, grinding power, acoustic emission, workpiece subsurface microhardness and microstructure for conventional method, MQL with pure oil (1:0) and MQL with water in 1:1, 1:3 and 1:5 oil-water proportions with and without grinding wheel cleaning (a jet of compressed air towards the wheel surface to remove the chips which clog the wheel pores). MQL with pure oil produced the worst results in this work, but dilution of oil in water benefited this lubricant-refrigerant technique. In addition, the diluted MQL 1:5 associated with wheel cleaning jet (WCJ) was the alternative method that most closely approximated the results of the conventional technique, indicating the potential for using MQL with WCJ widely in the industry. However, it is necessary to continue researching this technique in order it could even outperform the conventional method in all its output variables.

The influence of grinding conditions on surface roughness parameters of 20MnCr5 steel vacuum-carburised by single-piece flow method

The purpose of the experimental tests described in the article was to determine the effect of selected abrasive machining conditions on the value of surface roughness of 20MnCr5 steel samples. The samples were subjected to vacuum carburising (LPC) using the ‘single-piece flow’ method and high-pressure gas quenching (HPGQ) in a 4D Quenching chamber to obtain an effective case depth (ECD) of 0.4 mm. Next, the samples were ground with a Norton Vortex corundum grinding wheel. Cooling and lubricating fluid was delivered to the grinding zone using the flooding method (WET) and with the minimum quantity lubrication method (MQL). The samples were ground in one pass of the grinding wheel using two grinding depths – ae = 0.01 mm and ae = 0.02 mm. For each grinding test, surface roughness measurements were made using a stationary laboratory profilometer T8000 from Hommel Werke. These measurements enabled the determination of the 2D and 3D roughness parameters. Analysis of the measurement results showed that for the adopted test conditions, the use of the MQL method resulted in a decrease in surface roughness compared to the surface ground using the WET method. This property applies to both tested grinding depths.

Effect of MWCNT on surface roughness and burr height in MQL milling of AISI 430 ferritic stainless steel

Stainless steel materials have been used in many fields such as automotive, aviation, medical industries, etc. In addition, these materials are classified as difficult-to-cut materials due to low thermal conductivity and work-hardening tendency. Therefore, studies on machining of these materials have been performed in order to understand the basic of the process. In this study, surface roughness and burr height were investigated in MQL (Minimum Quantity Lubrication) milling of AISI 430 ferritic stainless steel. In MQL milling, commercial vegetable cutting fluid and MWCNT (Multi Walled Carbon Nanotube) reinforced vegetable cutting fluid were used. The milling experiments were also conducted under dry condition. In the experiments, uncoated WC (Tungsten Carbide) and TiN (Titanium Nitride) coated WC cutting inserts were used. Based on the experimental results, MQL method reduced the surface roughness and burr heights and better surfaces were obtained by using nanofluids in MQL method.

Analysis of the effect of sustainable lubricants in the turning of AISI 304 stainless steel

The rising environmental concerns and threats of contamination and pollution have led to the quest for sustainable cutting fluids. In order to maximize the use and efficiency of cutting fluids, the knowledge about them is necessary. In this study, the suitability of various natural vegetable oils as sustainable lubricants in machining was investigated using the turning of AISI 304 stainless steel on Colechester Master 3250 lathe. Three different natural vegetable oils were used such as palm oil, sunflower oil and coconut oil. The oils were applied as virgin oil using the minimum quantity lubrication method (MQL). The Taguchi method of design of experiments was applied in the study. Cutting parameters such as cutting speed, feed rate and depth of cut were used as input parameters and chip compression ratio and surface finish were used as responses to evaluate the suitability of these oils in machining of AISI 304 stainless steel. The result showed that sunflower oil has a better performance as cutting fluid.

Effect of TiO2 and Al2O3-ethylene glycol-based nanofluids on cutting temperature and surface roughness during turning process of AISI 1018

This paper presents the effect of TiO2 and Al2O3-ethylene glycol based nanofluids on cutting temperature and surface roughness during turning process of AISI 1018. Minimum quantity lubrication (MQL) method has been recognized in minimizing the usage of cutting fluid, as a step to achieve cleaner environment and sustainable machining. However, the low thermal conductivity of base fluid in minimum quantity lubrication system caused the insufficient removal of heat generated in cutting zone. Addition of nanoparticles to the base fluid was then introduced to enhance the performance of cutting fluids. In this study, the machinability of AISI 1018 (mild steel) was investigated under dry machining and nanofluid minimum quantity lubrication method. Two types of nanofluids (TiO2 and Al2O3 nanofluid) with concentration 0.05, 0.15 and 0.3 wt.% were used in this study. The experiments were conducted on lathe machine, using tungsten carbide as cutting tool. Three cutting speed (350, 550 and 750 m/min), three depth of cut (0.5, 1.0 and 1.5 mm) and fixed minimum quantity lubrication system nozzle pressure (5 bar) were applied throughout turning operation. To determine the relationship between machining parameters and cutting temperature and surface roughness values were measured. Based on results obtained, the cutting temperature of workpieces with usage of nanofluids in MQL system gave lower value compared to dry machining. The surface roughness of machined parts was also improved under NFMQL methods. In conclusion, when the nanofluid-MQL method was employed, the amount of cutting fluid was reduced and machining performance improved.

PREPARATION ENVIRONMENTALLY FRIENDLY NANO HEXAGONAL BORON NITRIDE (H-BN) ADDED CUTTING FLUID AND INVESTIGATION OF THE EFFECT ON CUTTING PERFORMANCE IN MILLING PROCESS OF HARD TO CUT MATERIALS.

In machining processes, MQL method is substantially preferred in terms of sustainable production because of lower usage of cutting fluid and better cutting performance in comparison with traditional techniques. On the other hand, it is also critical that the cutting fluid used is not hazardous to human and environmental health. In the present study, we aimed to investigate the cutting performance of AISI O2 steel in the presence of the cutting fluid containing various amounts of environmentally friendly Nano hexagonal boron nitride (Nano h-BN) based ethylene glycol (EG) by minimum quantity lubrication (MQL) method. Nano h-BN at 1% and 2% percentage by volume was added to the ethylene glycol and sonication was carried out for one hour for both prepared cutting fluids. Based on the experimental results using prepared cutting fluids, the highest cutting tool life was obtained in tests using 2% h-BN containing cutting fluid with 2.4 m cutting length. The improvement in tool life was approximately 46% using 2% h-BN containing cutting fluid compared to using 1% h-BN containing cutting fluid in milling tests. 2% h-BN containing cutting fluid compared to dry conditions in terms of tool life, the increase was approximately 78%. The improvement in surface roughness value measured on milled surface of workpiece material was approximately 60% using 2% h-BN containing cutting fluid compared to dry conditions. Compared to using 1% h-BN containing cutting fluid the improvement in surface roughness values was approximately 46%. A reduction in the cutting forces measured by the increased h-BN ratio in the prepared ethylene glycol based cutting fluid has occurred. As a result of SEM images and EDS analysis of worn tools, it was observed that the dominant wear mechanism was abrasion in all applied tests.

Selection of optimal cutting conditions and coolant flow rate (CFR) for enhancing surface finish in milling of aluminium alloy

Abstract Minimum quantity lubrication (MQL) is a traditional and worldwide accepted method for machining. To achieve better economy, environment and human wellness, MQL is preferred instead of flood cooling technique. In this study, the MQL method is applied during face milling of Al-6061using TiN coated carbide inserts. Coolant flow rate (CFR) along with cutting velocity and feed per revolution is selected as input process parameters to optimize the surface finish. In the design of experiments (DOE), Taguchi L9 orthogonal array is chosen for experimentation. Signal to noise (S/N) based on ‘smaller the better’ (surface finish) is calculated for each experiment. Analysis of means is applied to evaluate the optimum settings of input parameters. Significance and contribution of each parameter are evaluated by using analysis of variance (ANOVA). Results of ANOVA show that feed per revolution has a major contribution of 69.947% on surface finish.

Investigation on machining characteristics of TC4 alloy by simultaneous application of ultrasonic vibration assisted milling (UVAM) and economical-environmental MQL technology

Abstract The optimization of machining methods is one of important guiding principles for achieving high-quality, cost saving and environmental protection machining of difficult-to-machine materials in modern manufacturing. Considering the principles and advantages of ultrasonic machining (UM) method and minimum quantity lubrication (MQL) technique, the simultaneous application of UM and MQL methods is anticipated to further improve machining performance in terms of cutting force, surface quality and chip morphology. Theoretical analysis indicates that the MQL system in UVAM could provide enhanced lubrication and cooling performance because of the separate-type cutting mechanism, the surface acoustic and the cavitation phenomenon of resonant workpiece in UM. Conventional milling (CM) trials, general UVAM trials and combined UVAM&MQL trials were conducted to investigate the effect of UVAM and MQL methods on machining performance of TC4 alloy, where the results of CM and general UVAM could provide indispensable reference. Multifaceted comparisons are presented in machining results of CM, UVAM and UVAM&MQL trials in terms of time-domain analysis and frequency-domain analysis of milling force, average cutting force, surface topography, surface profile and surface roughness. The results show that cutting force features could be significantly affected under UVAM and UVAM&MQL condition compared with that in general milling due to intermittent cutting mechanism and the coupling effect of UVAM and MQL methods. The uniform micro-textured surfaces with improved profile fluctuations could be obtained when applying the UVAM&MQL strategy. Compared with surface roughness in CM and UVAM, the surface roughness in UVAM&MQL is improved by about 30–50% and about 20–30%, respectively. The excellent machining performance demonstrates the feasibility and effectiveness of simultaneously applying UVAM and MQL methods.