Lubrication Method Research Articles

Recent Advances on Coated Milling Tool Technology—A Comprehensive Review

The milling process is one of the most used processes in the manufacturing industry. Milling, as a process, as evolved, with new machines and methods being employed, in order to obtain the best results consistently. Milling tools have also seen quite an evolution, from the uncoated high-speed steel tool, to the now vastly used, coated tools. Information on the use of these coated tools in recent scientific researches was collected. The coatings that are currently being researched are going to be presented, highlighting some novel advances in the nanocomposite and diamond coatings area, as these coatings are seeing a growing use in the industry, with very satisfactory results, with performance and tool-life increase. Wear mechanism of various types of coatings are also a popular topic on recent research, as the cutting behavior of these coated tools provides valuable information on the tool’s-life. Furthermore, analysis of these mechanisms enables for the selection of the best coating type for the correct application. Recently, the employment of coated tools paired with sustainable lubrication methods as seen some use. As this presents the opportunity to enhance the coated tool’s and the process’s performance, obtaining better results, in terms of better tool-life and better surface finish quality, in a more sustainable fashion.

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.

Effect of roughness on meshing power loss of planetary gear set considering elasto-hydrodynamic lubrication

Meshing power loss is one of the most important parts in power loss calculation of planetary gear set. However, most of the conventional methods assumed the friction coefficient between gears as a constant value in the meshing power loss calculation, and most importantly, the influence of gear tooth surface geometry is usually ignored, for example, roughness. Therefore, a new meshing power loss calculation model for planetary gear set that considers tooth surface roughness is proposed on the basis of elasto-hydrodynamic lubrication method. With the proposed model, a planetary gear set dynamic model that considers friction force between gears is first established to study the time-varying meshing forces, sliding speeds, and curvature radii of the gear pairs. Then, an elasto-hydrodynamic lubrication model of the gear pair contact interface is constructed to investigate and modify the friction force distribution in the gear meshing process of the dynamic model iteratively until the meshing forces converge to stable values. Furthermore, the relationship between the tooth surface roughness and film thickness is studied in the elasto-hydrodynamic lubrication model. After that, the meshing power loss is calculated based on the obtained meshing forces, friction coefficients, sliding speeds, and so on. The results show that there is a sudden growth of the meshing power loss at the end of the meshing cycle, which has a good agreement with the meshing force impact. And, it is found that tooth surface roughness has a direct influence on the meshing power loss of sun–planet gear pair, which yields an increasing tendency as the surface roughness growing.

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.

Investigation on the angular contact ball bearings under low speed and heavy load with coupled mixed lubrication and quasi‐dynamic analysis

AbstractIn this paper, the angular contact ball bearings under low‐speed and heavy‐load conditions is studied with a coupled numerical method of mixed elastohydrodynamic lubrication (EHL) and quasi‐dynamic analysis. Compared with the quasi‐dynamic analysis without consideration of the mixed lubrication characteristics, the present coupled method reveals a smaller minimum film thickness and a larger frictional coefficient in ball‐race contact interface, leading to increases in the normal contact load, slide‐to‐roll ratio, and relative sliding velocity. Effects of operation condition (eg, rotational speed) and structural parameter (eg, inner raceway curvature coefficient and initial contact angle) on the contact and lubrication performances are discussed. The results show that a larger inner raceway curvature coefficient results in a smaller average film thickness and film thickness ratio, a larger frictional coefficient, and maximum contact pressure, while the increase in the initial contact angle has an opposite effect on these parameters.

Time-varying reliability analysis method for micropolar fluid elastohydrodynamic lubrication

Reliable lubrication of a bearing means that the roller and bearing are separated by the oil film, resulting in less wear and longer life. During the bearing lubrication process, some particles are produced due to wear and other reasons. Generally, the particle size in the micropolar fluid gradually increases with time. Moreover, velocity and load of the bearing are uncertain. It is very important to consider the time-varying reliability of bearing lubrication. In this paper, a time-varying reliability analysis method for micropolar fluid elastohydrodynamic lubrication is proposed based on response surface method and first passage method. The response surface method is applied to construct the response function of minimum oil film thickness, and the reliability model of lubrication is developed by the film thickness ratio. Then, the reliability of lubrication is calculated by first passage method. The numerical results show that both the accuracy and efficiency of the proposed method are high.

Time-varying reliability analysis method for micropolar fluid elastohydrodynamic lubrication

Reliable lubrication of a bearing means that the roller and bearing are separated by the oil film, resulting in less wear and longer life. During the bearing lubrication process, some particles are produced due to wear and other reasons. Generally, the particle size in the micropolar fluid gradually increases with time. Moreover, velocity and load of the bearing are uncertain. It is very important to consider the time-varying reliability of bearing lubrication. In this paper, a time-varying reliability analysis method for micropolar fluid elastohydrodynamic lubrication is proposed based on response surface method and first passage method. The response surface method is applied to construct the response function of minimum oil film thickness, and the reliability model of lubrication is developed by the film thickness ratio. Then, the reliability of lubrication is calculated by first passage method. The numerical results show that both the accuracy and efficiency of the proposed method are high.

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.

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.

A review on localised and multi-point aerosol application in minimum quantity lubrication machining

The minimum quantity lubrication (MQL) is prominent among the environmentally friendly machining techniques. Localised cooling and lubrication at multiple locations in the cutting zone is the latest development to improve efficacy and further trim down the consumption of metalworking fluid. The paper consolidates the strategies to use the MQL cutting fluids at the specific locations, vis-a-vis rake face, flank face and back of the chip. A critical analysis is made on cutting fluids, cooling strategies, process parameters, and their effect on quality. The latest developments and future directions in the framework of the hybrid lubrication method, hybrid cutting fluid and numerical modelling are presented.

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.

A Review On Green Machining Techniques

Industrial revolutions from Industry 1.0 to Industry 4.0 have drastically transformed human life. Industrialization with high productivity, zero-defect quality, improved efficiency, significant time saving and much better connectivity are some major benefits, but on the cost of environmental degradation. To overcome this challenge, globally sustainable manufacturing interventions are being given considerable importance. The term Sustainability is the ability of the processes, systems, products, or services to perform efficiently without affecting environment. From raw material processing to supplying final products, sustainability interventions are in place. Sustainability interventions incorporate various strategies and techniques to conserve natural resources and protect environment. Machining is an important segment in manufacturing sector to produce engineered parts and components for capital and consumer goods with the help of typical processes. These processes eventually result out in high environmental-footprints. It necessitated the development of green machining techniques such as hybrid machining, green lubrication methods, dry-cutting, energy-efficient and assisted machining processes etc. This paper discusses some of the green machining techniques developed in conventional and non-conventional machining domain for clean, green and safe environment. It is hoped that green machining techniques would greatly assist towards the success of industrial revolutions. The main objective of this paper is to facilitate researchers and academics by providing useful information in order to establish the field further.

Effects of Parameters of Machining on Cutting Force and Roughness when Machining AZ31 Magnesium Alloy

This project was done to learn the effects of cutting parameters on cutting force and roughness (surface roughnes) of AZ31 magnesium (Mg) alloy. Machining parameters involved in this project are cutting speed, feed rate, and lubrication methods. Deckel Maho DMU 50 eVolution high speed milling machine was using and uncoated carbide button insert was used as the cutting tool. Cutting force was measured during the milling process and roughness was measured after that and cleaning process to ensure no interference that would conflicted the results. The best machining parameters identified when feed rate at 0.05 mm per tooth, cutting speed are at 600 m per min, and minimum quantity lubrication was applied during the machining process. From analysis of variance (ANOVA) table generated by Minitab software, this project can conclude that feed rate, cutting speed, and lubrication methods are significant to cutting force and roughness when machining AZ31 Mg Alloy Therefore, the relationship of surface roughness and cutting force should be taken as a major key point in machining processes. In the automotive field, magnesium was used to fabricate an engine that place at front body due to reduce the weight of vehicle. This design can increase performance and balancing of weight [1].

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.

Effect of Nanofluid on Cutting Temperature in Turning of Inconel 625 with Ceramic Tools

Inconel 625 is used extensively in critical parts of aircraft, especially gas turbine engines. However, the high strength, which is one of the reasons of choice, considerably reduces the workability of this material. In such a case, the most preferred method is the use of cutting fluid. On the other hand, the fact that conventional cutting fluids adversely affect the environment, worker health and production costs concerns the enterprises. Recently, researchers and businesses have been working hard to reduce the amount of coolant without reducing production efficiency. In this study, some cooling/lubrication strategies have been tried to serve this purpose. In other words, the Minimum Quantity Lubrication (MQL) method and the MQL method containing 0.5% by volume nano Al2O3 additive were compared to dry processing. In addition, three different cutting speeds (120, 160, 200 m/min) and three different feeds (0.05, 0.1, 0.15 mm/rev) were chosen, as the behavior of the cooling / lubrication method under different cutting parameters was wondered. The Taguchi L9 vertical index was preferred for determining the number of experiments. Signal/Noise (S/N) ratio was effective in determining the optimum parameters. In addition, ANOVA analysis was performed to determine the effect levels of the parameters. In order to guide similar studies in the future, an estimation model was established through regression analysis. After the analysis of the test results, the optimum cutting temperature was obtained with a combination of vegetable cutting oil containing 0.5% Al2O3 by volume, cutting fluid of 120 m/min and feed rate of 0.05 mm/rev.

An investigation of carbon nanofluid minimum quantity lubrication for grinding unidirectional carbon fibre-reinforced ceramic matrix composites

Grinding is the most effective processing method for carbon fibre-reinforced ceramic matrix (Cf/SiC) composites (Liu et al., 2018). The effects of dry, flood, minimum quantity lubrication (MQL) and carbon nanofluid MQL conditions on grinding performance were studied in this research. Moreover, a method for effectively dispersing carbon nanoparticles was proposed. The experimental results showed that carbon nanofluid MQL conditions can provide significantly higher surface quality and lower grinding forces than the dry, flood and MQL conditions. In addition, the nanofluid poses a negligible threat to the environment and to workers, which means that carbon nanofluid has good application prospects in grinding processes. The influences of the nanoparticle concentration, air pressure, flow rate, nozzle distance and nozzle position on the grinding forces and surface quality were also investigated in this paper. According to the experimental results, the optimum parameters can be concluded as follows: the nanoparticle concentration was 5 g/L, the air pressure was 7 bar, the fluid flow rate was 80 mL/h, and the nozzle distance was 60 mm. According to the ground surface microtopography, matrix cracking, fibre pullout and fibre outcrop were the primary defect forms. In the grinding process, the debonding depth between the matrix and the carbon fibre depended on the sharpness and lubrication state of the abrasive grains. Long fibre debris, short fibre debris, fibre microparticles and SiC particles were the basic components of the grinding debris according to scanning electron microscopy (SEM) micrographs of the typical grinding chips from the Cf/SiC composites. This research is expected to investigate the application potential of carbon nanofluid MQL and propose a greener and more efficient lubrication method.

Effect of lubrication technique in tube drawing

Cold drawing process is widely used in steel tube manufacturing industry as it offers advantages like close dimensional tolerances, superior surface finish, flexibility in achieving different sizes and manipulated mechanical properties. This process needs to control friction parameters and lubrication extensively in order to obtain acceptable quality tubes and generally a phosphate and stearate coating has been the conventional approach to achieve this objective. Off late, some alternatives have emerged and a recently developed alternative lubrication system based on micro-porous lubricant carrierlayer generated on steel tube substrate by electroplating an alloy and selectively etching out one component of the alloy has been specifically taken up for detailed study. The porous layer is to trap the lubricant and act as lubricant reservoir in the metal deformation zone under the extreme pressures of cold drawing process. The attempt has been made to practically investigate the effectiveness of this alternative lubrication system for cold drawing process in tube manufacturing from an industrial perspective. Energy Dispersive Spectroscopy (EDS) and Scanning Electron Microscope (SEM) has been used in the analysis to verify that the aimed chemical composition and uniform distribution and to visualize the generated porous layer. Experimental investigations were carried out by subjecting the tube specimens (with lubricated porous layer) to the cold drawing process carried through a special drawing die attachment mounted on Universal Testing Machine (UTM). Comparison of the results with the conventional phosphate and stearate film based lubrication method has been made. The results show 10% of reduction in draw load and about 40% of improvement in surface roughness.

Modification of coolant fluid controller for minimum quantity lubrication (mql) methods with use of arduino uno-based control system

Coolant is important in the machining process. Excessive and uncontrolled use of coolant can cause high production costs, affect the human health and the waste of coolant polluting the environment. One method that has been used to reduce the amount of coolant is the limiting coolant distribution method or commonly called MQL (Minimum Quantity Lubrication). The MQL equipment which is available in the market has a relatively expensive, so a prototype of a coolant control system of MQL method has been designed and made. However, the prototype made not meet the desired specifications then a modified control system is added to the prototype. Prototype performance is compared before and after the control system being added. The duration of fluid drop and the output capacity of the fluid sprayed are measured to test the function of the device. It is found that with the addition of modified control systems, the performance of MQL cooling regulator is improved, but it is applied mostly for fluids which have viscosity ranging about viscosity of oil and cooking oil. For cooking oil fluid, the MQL tool performance increase as the capacity of the fluid decreases due to the control system being applied at all case of air valve openings for the diameter orifice of 2 mm. It is also found that at the aperture of the air valve of ¼, with a 10 second delay time and an orifice diameter of 2 mm, the capacity coolant sprayed is reduced from 107.348 ml/hr to 89.609 ml/hr when the modified control system is added. For the Bromus fluid, the capacity of the fluid decreases as the control system being applied. The MQL tool performance increase only occur in the smallest valve opening of ¼ that is about 9 to 26%. However, the capacity of Bromus types of fluid increase as the air valve openings increase.

Study on heavy-duty journal bearing lubrication based on Elasto-hydrodynamic lubrication method

Main bearing wear failure to become one of the main factors affecting the service-life of the engine, so it is necessary to form the effective analysis of the main bearing lubrication method, which is used in the design of main bearing lubrication and friction. In this paper, the model of substructure of V8 diesel engine is built based on flexible multi-body dynamics, the various nonlinear factors in the process of engine working process are considered, and the EHD of main bearings is analysed by the EXCITE software. On the basis of the V8 engine model, the bearing load and lubrication performances of different poly- condensation of main bearing are compared. The main bearing lubrication properties of the analysis results can be used for the engine lubrication system design and optimization.

A comprehensive investigation on the effect of flood and MQL coolant on the machinability and stress corrosion cracking of super duplex stainless steel

The poor machinability of super duplex stainless steels (SDSS) tends to generate detrimental tensile residual stresses that affect the service life of the component. Therefore, developing an efficient machining strategy to machine these components without any subsurface modifications is necessary. This work emphases on a detailed analysis of machinability and stress corrosion cracking resistance (SCC) of SDSS under different coolant environments (Dry, Flood, Minimum quantity lubrication). The cutting performance was evaluated using the machinability indicators such as tool wear, cutting force, surface finish, morphology of chips and residual stress. The chip morphology and residual stress results indicated that the thermally assisted deformation highly influences the machining of SDSS under all coolant environments. The overall machinability results revealed that MQL provided better performance than the other coolant and lubrication methods. To assess the SCC resistance, all the machined samples were subjected to SCC test under the chloride environment. The machined samples under MQL environment was observed with low surface crack density. This is due to presence of lower tensile residual stress with less surface defects. It was also observed that MQL samples exhibits lower localized corrosion (i.e) pit formation on the surface. These results clearly demonstrate that MQL is a recommended cooling and lubrication condition for the efficient machining of SDSS and to improve service life of the component.