Lubrication Method Research Articles

Surfactant free enhancement to thermophysical and tribological performance of bio-degradable lubricant with nano-friction modifier for sustainable end milling of Incoloy 925

An efficient method of lubrication and cooling for green machining is nanofluid minimum quantity lubrication (NMQL). Compared to other vegetable-based oils, coconut oil has the highest viscosity index, lubricity, and oxidative characteristics, making it a popular trending lubricant for decreasing friction. However, its performance at higher temperatures degrades owing to higher saponification value. In order to improve its performance, the solid nano-friction modifier (hBN) is dispersed in it, and the colloid is called a nanofluid. UV–Vis–NIR spectrophotometer, HR-TEM, and FTIR spectroscopy characterize nanofluid. The stability of nanofluid at 0.3 vol% of hBN has been observed to be the highest compared to other volume fractions. Compared to coconut oil, prepared nanofluid is superior in terms of increased thermal conductivity, thermal stability, and viscosity for all the tested temperature ranges. Nanofluid shows increased viscosity index (VI) by 20%, reduced contact angle by 45%, and lower coefficient of friction (COF) by 32% compared to coconut oil. Further performance of this modified biodegradable nanofluid under Minimum quantity lubrication (MQL) on end milling of Incoloy 925 has been studied. In order to compare the machining performance under different cutting environments, cutting temperature, cutting force, specific cutting energy, power consumption, carbon emission, chip morphology, surface topology/topography, and tool wear were evaluated. Finally, sustainability assessments for different cutting environments have been performed. Biodegradable oil-based NMQL-assisted machining has performed better than dry and MQL-assisted machining.

Tribological Characterisation and Modelling for the Fused Deposition Modelling of Polymeric Structures under Lubrication Conditions.

In recent years, additive manufacturing technology, particularly in plastic component fabrication, has gained prominence. However, fundamental modelling of the influence of materials like ABS, PC, and PLA on tribological properties in fused deposition modeling (FDM) remains scarce, particularly in non-lubricated, oil-lubricated, and grease-lubricated modes. This experimental study systematically investigates the effects of material type, lubrication method, layer thickness, and infill density on FDM component tribology. A tribology analysis is conducted using a TRB3 tribometer. The results indicate a coefficient of friction (CoF) range between 0.04 and 0.2, generally increasing and decreasing with layer thickness and filler density. The lubrication impact hinges on the material surface texture. The study models the intricate relationships between these variables via full-factor analysis, showing a strong alignment between the modelled and measured friction coefficients (an average error of 3.83%). Validation tests on different materials affirm the model's reliability and applicability.

Analyzing the Effects of Lubrication Techniques on CNC Spindle Bearing Heat: An Experimental Investigation

The machining ability and accuracy of a machine are determined by parameters such as the stiffness and load capacity of its spindle unit. In addition, the effectiveness and technique of lubrication and cooling can significantly affect the operational characteristics of the machine spindle. The current study investigated the effects of two different lubrication methods, grease and air-oil mixture, on the temperature which is generated at the spindle bearings of a Computer Numerical Control (CNC) machine. The temperature distribution and rise rate of the bearings were measured using a thermal imaging camera and thermocouples. The results indicated that the air-oil mixture method was more effective in dissipating heat and reducing the temperature of the bearings than the grease method, due to the direct cooling provided by the air-oil mixture to the bearing balls, resulting in improved lubrication efficiency and heat exchange with the environment. Compared to the grease lubrication method, the temperature of the bearings was lower by 7°C to 9°C depending on the position of the bearing on the CNC spindle. Therefore, it is recommended to use the air-oil mixture lubrication method, especially for high-speed processing on CNC machines. However, the discharge of oil particles from the ventilation system should be carefully controlled. Overall, the findings offer valuable insights into optimizing lubrication methods for CNC machines to enhance processing quality and reduce the impact of temperature on the bearing performance.

Introducing new green machining technology to enhance process performance and reduce environmental pollution in the metal processing industry.

The pursuit of enhanced cooling and lubrication methods for machining processes that are energy-efficient, environmentally friendly, and cost-effective is receiving significant attention from both academia and industry. The reduction of CO2 emissions is closely tied to electrical and embodied energy consumption. This study introduces a novel LN2 oil-on-water (LNOoW) cooling/lubrication (lubricooling) approach for the machining of Ti-6Al-4V alloy. Machinability aspects, energy-related aspects, environmental-related aspects, and economic aspects are measured and compared. More specifically, surface quality, electrical energy, cutting forces, and tool wear were measured in machinability aspects. Similarly, specific total energy and specific cumulative Energy Demand (S_CED), specific carbon emission, and production costs were measured to investigate the energy and environmental and economic aspects, respectively. The LNOoW provided the best machinability results compared with other approaches. Result found that LNOoW produced 37.5% better surface quality, removed 159.17% more material, and reduced 50.56% specific cutting energy and 53.63% specific costs as compared to traditional dry cutting conditions. The 39% increment in specific carbon emissions observed in the LN2 oil-on-water (LNOoW) approach in comparison to the dry-cutting method can be mitigated through the implementation of sustainable practices in the production of liquid nitrogen (LN2). The information provided in this study serves as a valuable resource for the development of environmentally friendly machining processes. The study also helps get the sustainable development goals (SDGs) of the United Nations.

Effect of magnetic field on the lubricating performance of nano magnetorheological grease at different temperatures

PurposeThe adverse effects of temperature on the lubricating properties of nano magnetorheological grease are reduced by applying of a magnetic field.Design/methodology/approachNano magnetorheological grease was prepared via a thermal water bath with stirring. The lubricating properties of the grease were investigated at different temperatures. Then the lubricity of the prepared nano magnetorheological grease was investigated under the effect of thermomagnetic coupling.FindingsAs the temperature rises, the coefficient of friction of grease lubrication gradually increases, surface wear gradually increases and lubrication performance gradually decreases. Compared with grease, magnetorheological grease has a decreased coefficient of friction and enhanced lubrication effect under the action of a magnetic field at different temperatures.Originality/valueA lubrication method using a magnetic field to reduce the effect of temperature is established, thereby providing new ideas for lubrication design under a wide range of temperature conditions.

Single-grain scratching of SiCf/SiC composite under minimum quantity lubrication: Force and material removal mechanism study

As one of the most novel fiber-reinforced ceramic matrix composites, SiCf/SiC composites are difficult to be processed machine materials. On top of that, the underlying material removal mechanism not yet completely understood. Along these lines, in this work, single-grain scratching orthogonal tests with different MQL methods were carried out to systematically analyze the influence of the different processing directions and lubrication methods on the material removal lubrication mechanism and the scratching force in the scratched surfaces. From the acquired results, it was demonstrated that the scratch force was the smallest when the processing direction is was 0° to the fiber direction. In addition, the utilization of MQL from vegetable oil can effectively reduce the cutting force. Diamond indenter caused significant damage to the surface of SiCf/SiC composites when the machining direction was 90° to the fiber direction, while narrow but deep grooves on the surface were observed when the angle was 0°. The dominant mode of material removal of SiCf/SiC composites was a brittle fracture, and the damage features mainly included direct fiber breakage, matrix fragmentation, fiber pullout, and fiber outcropping. The increase of the processing ratio of 0° and implementation of vegetable oil for MQL was proven as one of the best methods.

Study on the Effect of Hull Attitude on the Resistance Reduction of SWATH with Airflow Injection

With the development of the green ship concept in design and construction, how to reduce the resistance to reduce fuel consumption has become a focus of ship research. As an important drag reduction method, the air lubrication method has been applied to various ship types, but it is still a new method in the study of SWATH (small waterplane area twin hull) drag reduction. In this paper, the air lubrication method is applied to a SWATH model with an overall length of 2.5 m to numerically study the influence of the hull attitude on the air coverage and resistance reduction. The grid is verified by the grid independence and the experiment results. Then, the resistance of the SWATH model under different trim angles and drafts is calculated, and the air coverage on the surface is observed. The drag reduction rates of different areas, including the strut, underwater body, and fins, are analyzed, too. The results show that the slight trim by the head is more conducive to the resistance reduction of the SWATH model, and the resistance reduction rate can reach 39.11%. The draft mainly affects the resistance reduction of the strut, and the difference is more than 10%.

Comparison study on effect of different lubrication methods on tool wear and surface roughness during end milling of die tool steel

Among all the parameters of machinability evaluation, Surface roughness and chips are one the important parameters, which can influence the functionality and durability of the product machined. Previous research in the domain indicates that machining under dry and minimum quantity lubrication can be a sustainable alternative to the use of conventional flooded coolants. Also, it can minimize the negative impacts of chemical based flooded coolant on Environment, with satisfactory level of performance. This paper compares surface roughness and chips characteristics of Die tool steel material under Dry, Flooded and Micro Lubrication using uncoated carbide inserts. For attainable surface finish, quantification of contribution of input variables such as cutting speed, feed and lubrication mode, statistical method Analysis of Variance (ANOVA) is used. Surface roughness and Flank wear values under Micro-lubrication method significantly reduced compared to dry machining for machining length of 16,800 mm.

Design Optimization Methods for Forced Lubrication System Used in Automotive Transmissions

<div>Lubrication has been a major area of interest in engineering. Especially in vehicle transmissions, lubrication plays a very crucial role because gears and bearings are constantly subjected to heavy loads. Proper lubrication is essential for maintaining system performance and ensuring endurance life. Insufficient lubrication can lead to excessive wear, increased friction, and eventually, failures in the transmission components. However, excess lubrication can result in power losses due to the resistance offered by the excessive lubricant. Therefore, achieving effective lubrication using optimized lubrication system design is vital for ensuring the longevity and efficiency of the transmission system.</div> <div>Majorly, two types of lubrication methods are used in transmissions: splash lubrication and forced lubrication. This article focuses on forced lubrication, where the lubrication system actively delivers the required flow of lubricant to specific locations within the transmission. Pump outflow, orifice diameters, and channel dimensions are a few of the critical design parameters of the forced lubrication system. This article presents two design optimization methods: one using ANSYS DX (3D) and the other using GT-Suite (1D) tool. In the 3D method, ANSYS Fluent is used for CFD (computational fluid dynamics) simulations and subsequently ANSYS DesignXplorer (DX) is leveraged for design optimization. Predictions from CFD simulations are validated against physical test data and show good agreement (>90% match for flow rate). GT-SUITE is used in the 1D method, which is validated with predictions from 3D CFD method. The optimized designs obtained from both methods are effective in achieving the desired flow rate distribution, demonstrating their reliability. The ANSYS DX method provides an advantage in terms of reduced overall turnaround time (50% less) for the optimization. On the other hand, co-simulation (CFD+1D) approach can prove beneficial if it is required to perform minor routing changes on the lube system layout.</div>

Effect of Turning Parameter and Fiber Pullout on Machinability of Unidirectional EGFRP under Cryogenic Condition

The non-homogeneous and anisotropic nature of composites poses challenges during machining, requiring the use of specialized cutting tools. GFRP materials were selected for their excellent elasticity, corrosion resistance, and high strength, making them ideal for applications in the aerospace and automotive industries. In this work, the surface quality of UD-GFRP composite bars during CNC machining in diverse machining conditions (dry, wet, and cryogenic) was investigated while considering the fiber-pullout issue. The UD-EGFRP composite materials have been machined with a polycrystalline diamond tool. The Taguchi-L9 orthogonal-array technique is used to investigate and further analysis. Three independent-variables feed rate, rotational speed or cutting speed, and depth of cut have been taken into account for their optimal design to get better machinability of EGFRP. This study also investigates the delamination criterion in composites and establishes the correlation between its input parameters and output responses. The findings revealed that cryogenic machining led to a notable improvement of 25.21% in surface roughness compared to the other lubrication methods. Also, the reduction from 84 µm to 34 µm in fiber-pullout signifies that cryogenic cooling effectively mitigated the occurrence of fiber-pullout.

A sustained release lubrication method of agarose-sodium hyaluronate hydrogels for artificial joint.

The artificial joint prosthesis's surface is subjected to wear due to the destruction of the joint lubrication environment after surgery. In this study, an agarose-sodium hyaluronate hydrogel was used as lubricant additive in order to supply and preserve the lubricating fluid of artificial joint prostheses. A ball on disc experiment was conducted using this hydrogel to evaluate the lubrication efficiency and release rate under various frequencies. The results showed that this hydrogel could release lubricant under pressure and then absorb the released fluid after decompression. Furthermore, the agarose-sodium hyaluronate hydrogel acted as an effective transport mechanism to release sodium hyaluronate lubricant into the metal-on-polymer friction interface. Compared with pure water lubrication, the friction coefficient and wear volume were reduced by up to 62.9%, and 86.9% respectively. Moreover, the proposed lubrication method provided a long-term lubrication on artificial hip joints.

Optimization Control Method of Intelligent Cooling and Lubrication for a Geared Spindle

Optimization Control Method of Intelligent Cooling and Lubrication for a Geared Spindle

Mechanism and enhanced grindability of cryogenic air combined with biolubricant grinding titanium alloy

Grinding is an essential method for ensuring the machining accuracy and surface quality of difficult materials, such as aerospace titanium alloys. However, the deterioration of workpiece surface integrity due to thermal damage is the technical bottleneck of titanium alloy grinding. Therefore, a new enabling grinding technology for cryogenic air combined with a biolubricant is proposed. The introduction of cryogenic air leads to fundamental changes in the physical properties and lubrication mechanism in the grinding zone. On this basis, the formulas between the cryogenic air temperature and biolubricant temperature, kinematic viscosity, and surface tension coefficient are established. Under the same grinding parameters, compared with dry grinding, the normal force, tangential force, specific grinding energy, friction coefficient, temperature, and surface roughness value of cryogenic air minimum quantity lubrication decrease by 47.6%, 44.3%, 45.1%, 19.8%, 43.9%, and 46.3%, respectively. Then, the influence law of single and multiple factors on the grinding effect is discussed. When the peripheral speed, feed speed, and grinding depth are 30 m/s, 6 mm/s, and 30 µm, the optimal combination of factor parameters is a cryogenic air temperature of − 50 °C, an air pressure of 0.4 MPa, and nozzle inclination angle of 16°. Furthermore, on the basis of the multifactor orthogonal experiment, the quantitative mapping relationship between different grinding and influence factors is investigated to achieve optimal workpiece surface quality. This research provides a new effective method for improving the high surface integrity of grinding titanium alloys by using the cryogenic air minimum quantity lubrication method.

Comparative Cutting Fluid Study on Optimum Grinding Parameters of Ti-6Al-4V Alloy Using Flood, Minimum Quantity Lubrication (MQL), and Nanofluid MQL (NMQL)

Titanium alloys have been of paramount interest to the aerospace industry due to their attractive characteristics. However, these alloys are difficult to machine and require grinding post-processes for quality assurance of the products. Conventional grinding takes a long time and uses a flood coolant-lubrication technique, which is not cost effective nor environmentally friendly. Several studies have been performed to prove the viability and benefit of using Minimum Quantity Lubrication (MQL) with vegetable or synthetic-ester fluids. This work aims to find the optimum grinding parameters of creep feed grinding Ti-6Al-4V with a green silicon carbide wheel, using a flood lubrication system with water-soluble synthetic oil, MQL with ester oil, and nano-MQL (NMQL) using alumina-nanopowder homogeneously dispersed within an ester oil. It is concluded that at 0.635 mm and 1.27 mm infeeds, the three lubrication methods performed similarly. At an infeed of 1.905 mm, MQL did not provide desirable quality, though NMQL and flood lubrication performed practically identically. At a cross feed of 0.254 mm, an infeed of 1.27 mm, and a table feed rate of 6.7 m/min, these grinding parameters provide a material removal rate of 2163 mm3/min with a surface roughness across (Ra) of 0.515 µm. These parameters provide the quickest material removal rate while still maintaining industrial quality. This conclusion is based on environmental, economic, and qualitative results.

Approaches for Preventing Tool Wear in Sheet Metal Forming Processes

Sheet metal forming processes, the purpose of which is to give the shaped material appropriate mechanical, dimensional and shape properties, are characterised by different values of unit pressures and lubrication conditions. Increasing the efficiency of tool work by increasing their durability, efficiency and reliability is still one of the main indicators of increasing production efficiency. Tool wear in metal forming technologies significantly differs from the character of wear in other methods of metalworking, such as machining. This article presents the characteristics of tool wear mechanisms used in sheet metal forming. Possibilities of increasing the durability of tools by applying coatings produced by laser techniques, chemical vapour deposition and chemical vapour deposition are also discussed. Great emphasis is placed on self-lubricating and functional materials and coatings. Current trends in lubricants and lubrication methods in sheet forming, including tool texturing, are also presented.

Bearing Inner Ring Raceway Low-Temperature Aerosol Cooling Lubrication Grinding

A low-temperature aerosol cooling and lubrication grinding test bench was built to evaluate the cooling and lubrication performance of the low-temperature aerosol. The mechanism of grinding residual stresses in the inner ring raceway under the coupling effect of grinding force and grinding heat was studied, and the effects of the grinding process parameters and cooling and lubrication conditions on the distribution state of the grinding residual stresses in the surface layer of the inner ring raceway were revealed. The results showed that reducing the initial temperature of the grinding fluid could reduce the residual tensile stresses on the raceway surface. The results also showed that the low-temperature aerosol cooling lubrication method is conducive to the generation of the axial residual compressive stress of −500 MPa and tangential residual compressive stress of −300 MPa in the inner ring raceway surface layer of the bearing. Compared with the convective heat transfer coefficient, the effect of the initial temperature of the grinding fluid is smaller.

Enhanced grindability and mechanism in the magnetic traction nanolubricant grinding of Ti-6Al-4 V

Minimum quantity lubrication with nanolubricants is an efficient and environmentally friendly lubrication method with the greatest potential to replace traditional metal grinding with fluids. However, it faces the technical challenge of insufficient infiltration capacity in complex grinding zones, leading to the deterioration of tribological properties and surface integrity, especially in the large contact length grinding (LCLG) of difficult-to-machine aerospace materials. In this paper, we present a novel magnetic traction nano-lubrication (MTN) method, wherein a magnetic-assisted device is used to generate traction energy for increasing the infiltration capacity of magnetic nanolubricants in grinding. However, the effectiveness and mechanism of MTN grinding have not been studied. First, our results showed that in general grinding, the Fe3O4/graphene nanolubricant showed better cooling and lubrication performance than palm oil, Fe3O4 nanolubricants, and graphene nanolubricants. In MTN grinding, grinding force and grinding temperature had reduced by 35.8% and 66.4%, respectively, with the arithmetical mean height Sa decreasing by 27.5%. Plastic uplift and debris adhesion on the workpiece surface were also eliminated. Second, the improvement in infiltration performance under magnetic field traction was further verified by the LCLG experiment. Finally, the unique infiltration and antifriction mechanism of MTN were analyzed. The MTN technology solves the technical bottleneck of poor surface integrity and provides a solution for the LCLG of materials with high hardness and toughness and low thermal conductivity.

Study on Lubricating Performance of the Bubbly Oil Under High Shear Rate—Part 1: Generation Method and Viscosity Measurement of the Bubbly Oil

Abstract Bubbly oil lubrication is a type of lubrication method that has a high potential for application. However, the lubricating performance of the bubbly oil has not been thoroughly considered. This paper aims to investigate the lubricating performance of the bubbly oil including the generation of the bubbly oil, viscosity characteristics of the bubbly oil, and the application study of the bubbly oil lubrication. Due to space limitation, the work is divided into two parts. Part 1 focuses on the generation method of the bubbly oil, observation of the bubbly oil, and the measurement of viscosity characteristics under a high shear rate. Part 2 focuses on the application study of the bubbly oil lubrication in high-speed bearing. A generation method for the bubbly oil was proposed by a combination of the dispersed-air method and the pressurized dissolution one. An experiment setup for generating the bubbly oil, an observation system for the bubbly oil, and a specially-designed viscometer for the bubbly oil were developed. The research results show that the generation method for the bubbly oil is of high efficiency and stability and the observation system is operational.

An investigation on performance of castor oil and Pongamia oil based cutting fluid in MQL milling of aluminium alloy 6061

The expense of coolant in milling processes accounts for such a significant portion of overall production costs, research efforts are presently concentrated on finding ways to reduce or do away with the need for lubrication. The environment, the performance of the machining, and the prices of the machining can all benefit from the decrease or elimination of traditional fluid. By employing the Minimum Quantity Lubrication Method, one is able to cut down on lubrication costs while also lowering the potential danger to the health of workers. While end milling aluminium 6061 with a SINOMILL VMC300 and an HSS end mill tool at three distinct spindle speeds (1000, 1500, and 2000 rpm), three distinct doc(0.25, 0.5, and 0.75 mm), and three distinct feed(100,150,200 mm/min), surface roughness (Ra) was measured in dry milling, MQL with base fluid (Pongamia oil, castor oil), conditions. The reduction in Ra is reported as a 12.89% with base fluid (Pongamia oil), in comparison to dry milling. When compared to dry milling, the reduction in Ra that was recorded when using base fluid (castor oil) was 33.72%. In this experiment it was carried out by the Drop shape analyzer (which was manufactured by Kruss), it was found that the contact angle in castor oil is superior to the contact angle in pongamia oil, and the values of contact angle are 43.4 and 47.8 respectively.

Dry and MQL Milling of AISI 1045 Steel with Vegetable and Mineral-Based Fluids

The use of mineral-based cutting fluids in machining has the drawback of affecting the environment and industries are under pressures to reduce its use in favor of cleaner productions. In this regard, the vegetal-based cutting fluids can be a superior alternative, provided they improve the technical outcomes. In the milling process, dry cutting is commonly performed, however, the application of cutting fluids using the minimum quantity of lubricant (MQL) method has proven advantageous when compared with dry machining. Furthermore, in the midst of the availability of several cutting fluids in the market, the testing of their individual performance can ascertain their potential and effectiveness for a particular application. This study examined the performances of two vegetable-based and one mineral-based oils applied by the MQL method, followed by their comparison with dry cutting amid end milling of AISI 1045 steel with TiAlN-coated cemented carbide inserts. The cutting temperature, machining forces, power consumption, workpiece surface roughness, tool life, and tool wear mechanisms were chosen as the output parameters. The experiments were conducted using two cutting speeds (150 and 200 m/min) and feed rates (0.07 and 0.14 mm/tooth), and constant axial (1 mm) and radial depths of the cut (25 mm). The temperature was measured using a K-type thermocouple soldered to the part and an infrared camera. The power was monitored with a Fluke 435 energy analyzer, and the machining force components with a Kistler dynamometer. The worn inserts were inspected under a scanning electron microscope (SEM) to analyze the tool wear mechanism. The MQL-assisted application of the cutting fluids notably lowered the cutting temperature and increased the tools’ lives. However, the cutting fluids did not reflect any significant effect on the machining force, power consumption, or surface roughness. Among all the analyzed cutting conditions, the abrasive wear mechanism dominated, damaging the cutting edges, flank, and rake surfaces of the cutting tools. In addition, adhesive and diffusion wear mechanisms were also observed.