Lubrication Machining Research Articles

Cutting force prediction in ultrasonic-assisted milling of Ti–6Al–4V with different machining conditions using artificial neural network

AbstractTi–6Al–4V alloy has superior material properties such as high strength-to-weight ratio, good corrosion resistance, and excellent fracture toughness. Therefore, it is widely used in aerospace, medical, and automotive industries where machining is an essential process for these industries. However, machining of Ti–6Al–4V is a material with extremely low machinability characteristics; thus, conventional machining methods are not appropriate to machine such materials. Ultrasonic-assisted machining (UAM) is a novel hybrid machining method which has numerous advantages over conventional machining processes. In addition, minimum quantity lubrication (MQL) is an alternative type of metal cutting fluid application that is being used instead of conventional lubrication in machining. One of the parameters which could be used to measure the performance of the machining process is the amount of cutting force. Nevertheless, there is a number of limited studies to compare the changes in cutting forces by using UAM and MQL together which are time-consuming and not cost-effective. Artificial neural network (ANN) is an alternative method that may eliminate the limitations mentioned above by estimating the outputs with the limited number of data. In this study, a model was developed and coded in Python programming environment in order to predict cutting forces using ANN. The results showed that experimental cutting forces were estimated with a successful prediction rate of 0.99 with mean absolute percentage error and mean squared error of 1.85% and 13.1, respectively. Moreover, considering too limited experimental data, ANN provided acceptable results in a cost- and time-effective way.

Effect of nanoparticles in cutting fluid for structural machining of Inconel 718

ABSTRACT Recently nanofluids have pinpricked a tremendous research interest among the institutions and manufacturing industries because of a good coefficient of conductive heat transfer and a high impact of lubrication in machining. In this study, nanofluids of powders (Al2O3 and TiO2) each with concentrations of 0.5 and 1 gm in 100 ml of ACTIV 4T SAE20W40 engine oil were prepared and compared with dry and lubricant condition for the turning of Inconel 718 superalloy using MQL methodology. Turning was being done in MTAB CNC lathe machine with 200, 300 and 400 rpm speed keeping a constant feed of 0.05 mm/rev and constant depth of cut 0.5 mm by using carbide insert with a positive rake angle of 15 degrees. Machining characterisation through SEM was carried out. The experimental results show that the surface roughness, chip thickness and chip morphology are more suitable at a speed of 400 rpm for machining of Inconel 718 for a concentration 1 gm of Al2O3. The influence of cutting parameter and nanoparticle concentration was also being analysed with ANOVA. The machining results obtained for every concentration are analysed so that the optimisation of different parameters is to be obtained for the structured machining of Inconel 718.

Characterization and experimental investigation of rheological behavior of oxide nanolubricants

Nanolubricants are nano fluid, colloidal nanoparticle suspension, which are specially used for machine lubrication of the engine. Nanolubricants exhibit special tribological properties that have potential applications in mainly automotive industries. Performance of an engine is a function of the lubricant being used. A study of rheological behaviors of nanolubricants has been beneficial in understanding the influence of nanolubricants on shear rate and shear stress. This study is concerned with characterization and rheological behavioral studies of five nanolubricants, i.e., SnO2, TiO2, Fe3O4, CuO and ZnO mixed with engine oil at 1% volume by weight concentration. In this study, the result showed that the shear rate was independent of viscosity confirming the Newtonian behavior of these nanolubricants. Non-linear decrease in the shear viscosity, with the rise of the temperature, was observed as well from the result. This non-linear behavior observed in these nanolubricants open up the potential for high-temperature application of these nanolubricants which would greatly benefit automotive industries.

Modeling of tool wear in machining of AISI 52100 steel using artificial neural networks

Machining is an arduous process for both the cutting tool and workpiece material. Conducting a series of machining tests involves a lot of money and time. It is important to prevent time consuming runs and prioritize technology. Hence, in this investigation, artificial neural network (ANN) approach is employed to estimate the cutting tool wear. From the experimentally obtained values, the input variables chosen for ANN modeling are cutting speed, feed and depth of cut corresponding to the output variable tool wear. The ANN modeling comprises Levenberg-Marquardt (trainlm) and tangent sigmoid (tansig) as training and testing functions respectively. Optimum architecture 3–6-6–1 is obtained based on the mean sum squared error (MSE) and average error (AE) of input data. Tool flank wear is assessed in three different machining environments such as dry machining, wet machining (flood cooling) and minimum quantity lubrication (MQL) machining. The emulsifier oil based cutting fluid is used as cutting fluid in wet and MQL machining. ANN model predicted values are compared with experimental results. Based on the correlation coefficient factor, it was observed that the prediction of ANN is high, showing a significant harmony between predicted response and experimental output.

Kinematic Viscosity Prediction of Nanolubricants Employed in Heavy Earth Moving Machinery Using Machine Learning Techniques

Recent researchers widely used nanoparticle additives for improving thermal and rheological properties of machine lubricant. In present study the effect of Al2O3 and CeO2 nanoparticles on transmission oil (SAE30), hydraulic oil (HYDREX100) and gear oil (EP90) of heavy earth moving machinery is investigated. Nano-lubricant samples are prepared in 0.01–4% nanoparticle volume fraction range. Four machine learning techniques namely decision tree (DT), random forest (RF), generalized linear models and neural network (NN) have been used to predict the kinematic viscosity for Al2O3 and CeO2 nanolubricants. Further, multi-criteria decision-making technique named technique for order of preference by similarity to ideal solution have been used to find the best predictive method in each category of the nanolubricants. DT, RF and NN methods are found to be most accurate in kinematic viscosity prediction of transmission oil (R2 = 0.861), hydraulic oil (R2 = 0.971) and gear oil (R2 = 0.973), respectively.

High-speed machining of aluminium alloy using vegetable oil based small quantity lubrication

In an attempt to investigate the effectiveness of vegetable oil based small quantity lubrication in high-speed machining of aluminium, this study finds that its usefulness is more significant in an intermittent cutting process like end milling than in turning, where continuous cutting happens. The investigation was carried out using small quantity lubrication aerosol, produced by air atomization of sunflower oil at the rate of 100 ml/h for each cutting zone. In the high-speed turning operations, uncoated and polycrystalline diamond–tipped WC inserts were used. 5%–20% reduction of cutting force could be realized by small quantity lubrication application, compared to dry environment. The highest order of reduction was observed when the cutting velocity was increased from 700 to 1000 m/min. At lower velocities, small quantity lubrication effect was almost insignificant. However, high-speed end milling operations received substantially superior benefit by small quantity lubrication application. The reduction of feed force was 30% or more among different cutting speeds. The beneficial effect of small quantity lubrication application was significantly more in machining commercially pure 1050 grade of aluminium than 7075 alloy. The required prevalence of the thick-film lubrication at the interface of chip and tool rake for arresting any possible diffusion of aluminium to tool material was significant in the intermittent cutting since every cutting edge drew in fresh micro-droplets of lubricant before resuming cutting in its next cycle of engagement with workpiece. Interestingly, the end milling performance of small quantity lubrication–assisted uncoated carbide was so good that diamond-coated tools were not necessary. Surface roughness profiles, chip morphology and traces of built up edge formation were critically investigated and the results clearly indicated the predominantly more favourable outcome of small quantity lubrication application in end milling, compared to turning.

In-house development of eco-friendly lubrication techniques (EMQL, Nanoparticles+EMQL and EL) for improving machining performance of 15–5 PHSS

Emulsion based cutting fluids are traditionally used to extract the heat in cutting zone but are found non-sustainable due to adverse impact on environment and worker's health. To provide a superior machining performance with lower consumption of cutting oil, indigenously developed electrostatic minimum quantity lubrication (EMQL), hybrid NPs immersed EMQL (HNEMQL) and electrostatic lubrication (EL) machining techniques are proposed for the practical range of cutting parameters. Overall, 10.75%, 4.88% and 2.25% lower values of power consumption are found in HNEMQL as compared to dry, EL and EMQL respectively for turning 15–5 precipitation-hardened stainless steel (PHSS). The better results of surface roughness and chip reduction coefficient are found for EL and HNEMQL techniques respectively as compared to other cutting fluid strategies.

New approach for cooling and lubrication in dry machining on the example of internal cylindrical grinding of bearing rings

This paper describes a new method of hybrid cooling and lubrication of the machining zone conducted in dry conditions on the example of internal cylindrical grinding of bearing rings. The idea of the method consists in simultaneous application of a cooling agent in the form of compressed cooled air generated by the cold air gun (CAG) nozzle and a solid antiadhesive and lubricating agent fed to the grinding zone in the form of an impregnate in grinding wheel. Hexagonal boron nitride hBN was used as impregnate. The method of hybrid supply of cooling and lubricating agents configured in such a way allows for dry machining process (without the use of liquid coolants), simultaneously performing the cooling and lubricating functions of liquid coolants in a different, more environmentally friendly form. The article presents the characteristics of a new hybrid method of cooling and lubrication of the machining zone, the results of simulation studies on the flow of compressed cooled air (CCA) and heat exchange in the grinding zone, as well as the results of experimental studies on the process of internal cylindrical grinding of 100Cr6 steel bearing rings using the described method. The conducted simulation tests made it possible to determine the most advantageous conditions of feeding the CCA stream into the grinding zone by means of a two outlet supply line for effective cooling of the grinding zone. The most important result of the experimental research was to demonstrate the possibility of five times longer wheel life in the dry grinding process by using the proposed hybrid method of cooling and lubricating in relation to grinding with a non-impregnated wheel without the application of cooling and lubricating agents. The application of the proposed hybrid method of cooling and lubrication significantly reduced the grinding wheel volumetric wear Vs and made it possible to carry out the machining in stable conditions with more than 4 times higher value of grinding ratio G. Proposed method show its advantages also in relation to workpiece and grinding wheel temperature as well as reduction of grinding wheel cloggings.

EXPERIMENTAL ANALYSIS AND OPTIMIZATION OF THE CONTROLLABLE PARAMETERS IN TURNING OF EN AW-2011 ALLOY; DRY MACHINING AND ALTERNATIVE COOLING TECHNIQUES

The latest trends in machining research show that great efforts are being made to understand the impact of different cooling and lubrication techniques as well as cutting parameters on machining performances. This paper presents the investigation results of different cutting parameters and different cutting environments such as dry machining, minimum quantity lubrication (MQL) and minimum quantity lubrication with compressed cold air (MQL+CCA) on average surface roughness, cutting force and material removal rate. The experiments were designed based on three input parameters and three different cutting environments when turning of EN AW-2011 alloy. Taguchi-based grey relational analysis was used to identify the optimal process parameters by which minimum values of surface roughness, minimum value of cutting force and maximum value of material removal rate will be achieved. The results showed that minimum quantity lubrication in the stream of compressed cold air, in comparison to dry and minimum quantity lubrication machining, gives the best machining performances. Therefore, the use of MQL + CCA method, which reduces the amount of lubricant may represent in the described extent of turning operations an alternative to turning processes most often carried out by wet method that causes considerable costs for purchasing, maintaining and using cutting fluids.

Sustainable Turning of Biocompatible Materials Using Eco Nano-Mist Technique

In today’s industrial scenario, the requisite for elevated efficiency, better economic viability and higher quality asks for immense improvements in the cutting process stability. Such machining at higher cutting speeds and cutting depths causes an immense amount of heat generation at the work tool interface. The industry makes utilization of cooling techniques to contravene these ill-effects. These techniques make utilization of chemical coolants which are non-biodegradable in nature and consumed in immense quantities. In this study the role of minimum quantity lubrication (MQL) or green machining was experimentally evaluated when utilizing nanoparticle enriched coolants. The effect on the wear and roughness values while turning commercially pure Titanium (Grade 3) was analyzed. Experimentation was performed in two phases. In the first phase, the comparison in dry, flood and MQL process was made. The experimental design was composed factorially and 16 experiments were performed. Analysis was carried out utilizing ANOVA and the results were compared. In the second phase, a graphical cognation was established between the coolant application rate with both surface roughness and flank wear values. It was concluded that the nanoparticle enriched coolant i.e. the “eco nanomist”technique was more efficacious when machining the biocompatible Titanium grade 3.

Investigations on machinability aspects of AISI 52100 with minimum quantity solid lubrication

Sustainability has been a major concern of today’s manufacturing industries. Various efforts have been made to improve the productivity and performance of machining. It is always aimed to reduce the heat generated during machining by various cooling and lubrication approaches. In the present work, efforts have been made to assess the effectiveness of minimum quantity lubrication and solid lubricants in machining. Experiments have been performed under MQL and MQSL environment with selected flow rate (300 ml/hr), 20 wt% of calcium fluoride (CaF2) and 10µm particle size of solid lubricant and results are compared with dry and flood cooling environment. The process performance is observed by measuring surface roughness produced, tool flank wear, the microhardness of machined workpiece, and forms of the chip produced. Results revealed the superiority of lubricant mixture applied in form of MQSL due to enhanced lubricating properties imparted by solid lubricant added with MQL.

Experimental investigations on the applicability of solid lubricants in processing of AISI 4140 steel

Machining of material is the most versatile and precise process because of its various application in manufacturing industries. As the result of shear deformation of workpiece, lot of heat is generated in machining. Cutting fluids are used to reduce the effects of heat generated during machining. However, at very high temperature and pressure conditions liquid become volatile and losses its properties. Also, these cutting fluids are not eco-friendly and these are hazardous to health. Solid lubricants having ability to with stand very high pressure and temperature can be utilized to improve the machining by reducing the friction co-efficient at tool-work interface. Hence, present study aims to investigate the applicability of solid lubricant in machining of AISI 4140 steel. An experimental setup has been developed to supply the solid lubricant in machining and machining performance is studied under dry, flood cooling and solid lubricant assisted machining. Comparison of results showed considerable improvement in surface quality, decrease in power requirement and also reduction in tangential force with solid lubricants compared to dry and wet machining process.

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.

Istraživanje mikrostrukture, mehaničkih svojstava i obradljivosti hibridnog nanokompozita na bazi Al7075/SiC/h i BN proizvedenog livenjem istiskivanjem uz pomoć ultrazvuka

The present research article deals with the microstructure, mechanical properties and machinability investigation of squeeze-cast Al7075 and Al7075/SiC/h-BN hybrid nanocomposite. The Al7075 alloy nanocomposite has been reinforced by micro-size SiC (1 wt.%) particles and h-BN (0.5 wt.%) nanoparticles, prepared via ultrasonic-assisted melt-stirring approach. In order to achieve the better mixing of reinforcements, diminish the agglomeration effect of nanoparticles and improved wettability of the particles in the melt, SiC and h-BN powders have been ball-milled for the duration of 4 h. The microstructural investigation of the prepared nanocomposite was carried out by using optical microscopy (OM), scanning electron microscopy (SEM) and x-ray mapping analysis. The x-ray mapping and optical microscopic analysis show good dispersion uniformity of reinforcements and refinement in the grain sizes. The investigation of mechanical properties of hybrid nanocomposite shows the significant improvement of about 35.33 %, 21.69 %, 13.87 % and 12.27 % in the offset yield strength, ultimate tensile strength, Rockwell hardness and microhardness (Vickers), respectively. Furthermore, the machinability analysis has been performed to examine the influence of several machining parameters such as cutting speed, feed rate and depth of cut on the surface roughness, cutting force and chips length of the squeeze-cast hybrid nanocomposites under dry and minimum quantity lubrication (MQL) machining conditions. The outcomes of the machinability analysis for hybrid nanocomposites are compared with the Al7075 specimen and discussed.

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

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

MQL machining of high strength steel: A case study on surface quality characteristic

The present paper highlights investigation on hard turning of high strength EN24 steel using multilayer coated carbide insert (TiN/TiCN/Al2O3/ZrCN) under minimum quantity lubrication environment for surface roughness. Measured surface values are found to be less than 1 µm which is much below the surface roughness criteria of 1.6 µm. It indicates that quality components can be obtained during MQL assisted machining of high strength EN 24 steel. This indicates proper cooling and lubrication of machining zone occurred due to application of pressurized oil mist. Developed regression model has been found to be significant because determination coefficient i.e. R2 close to unity (0.9) and p-value is less than 0.05 at 95% confidence level. Hence, environmental friendly minimum quantity lubrication machining can be effectively utilized for production of quality components in industrial shop floors for ecological and economical benefits.

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.

Investigation of surface roughness and chip morphology of aluminum alloy in dry and minimum quantity lubrication machining

Aluminum alloys are used in different sectors due to their lightness, high strength ratio, corrosion resistance, and heat conduction, and electrical conduction, non-magnetic and non-toxic properties. Despite these properties, determination of surface quality is a critical factor for improving the functional properties of aluminum alloys such as high fatigue strength, corrosion behavior, and wear resistance. In this study, the effect of high-speed machining of Al7075-T6 aluminum alloy on the surface quality of Al7075-T6 alloy was investigated. Besides, the effect of different conditions on-chip formation was studied. The experiments were carried out in three different cutting parameters in dry and minimum quantity lubrication (MQL) conditions. It was found the surface quality of the Al7075-T6 alloy workpiece was improved when the test results performed in the MQL condition were compared to the dry condition. When the chip structure is examined, longer chip formation occurs in the MQL environment than a dry environment. It was observed that there was no significant difference in surface quality and chip morphology of the Al7075-T6 workpiece at different cutting speeds.

A study of viscosity and thermal conductivity of vegetable oils as base cutting fluids for minimum quantity lubrication machining of difficult-to-cut metals

The properties of environmentally friendly, sustainable, and renewable cutting fluids are very important to effective machining of difficult-to-cut materials under minimum quantity lubrication (MQL). This paper presents the experimental investigation of viscosity and thermal conductivity of three vegetable oils for use as base cutting fluids: modified high oleic soybean oil (HOSO), refined low oleic soybean oil (LOSO), acculube LB2000 (LB2000) oil, and mineral oil–based emulsion cutting fluid (EC) as benchmark and at temperature from 25 to 70 °C. The results show that viscosity of all vegetable oils decreases exponentially with temperature, and are significantly higher than that of EC. HOSO shows an enhanced viscosity of 6.03% compared to LB2000, 25.69% compared to LOSO, and 4688.30% compared to EC at 30 °C temperature. Thermal conductivity of soybean oils and LB2000 is similar, decreases gradually from 0.192 to 0.179 W/mK, not significantly affected by temperature and very low compared to EC. EC increases from 0.698 to 1.857 W/mK between 25 and 50 °C and decreases from 1.857 to 0.762 W/mK between 50 and 70 °C. Critical temperature of EC is around 50 °C. Shear stress–shear rate plots of vegetable oils show linear relation typical of Newtonian fluids. The R-square of HOSO was greater than 0.99 at all investigated temperature and better than the observed values for LB2000, LOSO, and EC. HOSO with higher oleic fatty acid composition shows the most significant viscosity enhancement and oxidation stability, and is recommended as alternative to EC and based-cutting fluid for MQL machining.

Performance comparison of dry, flood and vegetable oil based minimum quantity lubrication environments during CNC milling of Aluminium 6061

Abstract The minimum quantity lubrication in machining has been emerged as the sustainable manufacturing techniques and being widely explored for industrial applications since last few years. The aim of this paper is to explore the CNC milling performance while machining Aluminium 6061 under three different environments viz. dry, flood and vegetable oil based minimum quantity lubrication (MQL) technique. Taguchi L9 array was used to design the experiments, for three machining input parameters viz. cutting speed, feed rate and depth of cut; considering the efficient use of limited resources. A fresh TiAlN coated carbide PVD insert was used in end milling of Aluminium 6061T6 for each experimental run. A total of 27 experiments were performed for dry, flood and MQL environments. Average surface roughness was analysed for each experiment and machining parameters for better surface finish were optimized. It was observed that MQL provides the best surface finish out of all three cooling environments. Tool wear was also found to be reduced significantly in MQL environment as compared to dry and flood techniques. It was concluded that MQL cooling technique can be used as a better alternative to dry or flood cooling method.