Papers by Keyword: Minimum Quantity Lubrication

Abstract: In this study, dry, minimum quantity lubrication (MQL) using vegetable-based oil and multi-walled carbon nanotube-reinforced nanofluid-assisted MQL (N-MQL) burnishing conditions and various burnishing speed and depth of burnishing values were used in the sustainable roller burnishing of additively manufactured AlSi10Mg alloy which is widely used in the aviation and automotive industries due to its superior mechanical properties, and burnishing performance was investigated in terms of surface roughness and power consumption. Then, experimental results were evaluated statistically using Taguchi and variance analysis. N-MQL with a burnishing speed of 10 m/min was shown to be the optimum burnishing condition for both surface roughness and power consumption. The optimum burnishing depth was 0.02 mm for power usage and 0.06 mm for surface roughness.

Abstract: This research explores the feasibility of utilising supercritical carbon dioxide (scCO₂) as a coolant coupled with minimum quantity lubrication (MQL) as a lubricant, to replace conventional coolant and lubricating fluids (CLF’s) in small diameter deep hole drilling (DHD) of austenitic stainless steel (AISI 304L). The study investigates the impact of scCO₂+MQL on hole quality, surface roughness, and tool wear parameters in comparison to high-pressure soluble oil cutting fluid (HPC). The motivation stems from the need to supply sustainable and environmentally conscious CLF alternatives within the machining industry, specifically addressing the reduction of dependence on traditional HPC’s.ScCO₂+MQL offers significant advantages under specific conditions, particularly with mid-range feed rates and higher cutting speeds. On average, drilling under scCO₂+MQL conditions achieved a success rate 71% as effective as when drilling with HPC, however the difference can be attributed to the set of cutting conditions optimised primarily for HPC, not for scCO2. The results indicate the viability of scCO₂+MQL and its ability to produce results comparable to HPC. It also emphasises the complexities of transitioning from traditional CLFs to sustainable alternatives like scCO₂+MQL in DHD processes. The outcomes present an encouraging case for the environmental and cost benefits associated with scCO₂+MQL. However, it also highlights the need for further investigation and optimisation, particularly in tool design, to enhance performance and address the existing challenges.

Abstract: Minimum Quantity Lubrication (MQL) has been proved to be an efficient lubricant technique in machining that increases tool life, improves surface roughness, facilitates the recycling of the resulting chips, brings more sustainable practices in terms of minimum use of lubricants, and reduces the operators’ exposures to toxic particles with respect to conventional cooling practices. In order to increase the performance of MQL, nanoparticles of Al₂O₃, MoS₂, SiO₂ graphite and graphene among others have been recently introduced into MQL lubricants. This new approach, called nanoMinimum Quantity Lubrication (NMQL), has been proved to provide better thermal conductivity and lower friction coefficients during cutting, which in turns means higher cutting tool life and lower cutting forces. In this paper, a stable SiO₂ -based nanolubricant was produced and characterized. A tribological analysis was conducted on SiO₂ nanolubricants to be used on MQL operations. Operational issues related to particles deposition along time, loss of nanolubricant properties when it comes from the MQL system and mist generation were also analyzed.

Abstract: Metal cutting is the way of processing the workpiece with tool having sharp cutting edges of different materials generating chips of different shapes and sizes. In present era of industry 4.0, metal machining should not be unrated during processing of hard grades metals and superalloys where large amount of cutting forces are generated. Also, the measurement of cutting forces provides the basic of economical machining and hence accurate evaluation in experimental and analytical manner has great importance. The traditional models of metal cutting have disagreement with experimental results due to missing of important mechanics terms. With the development of digital technology, the errors in calculation of cutting force have also been shortened due to consideration of terms absent in conventional models. In present investigation, the cutting forces have been evaluated experimentally using dynamometer and analytically with Astakhov’s methodology during turning of EN-31 steel. The results revealed that 12.9% observations have deviation more than 20%, whereas 16.67 % has zero deviation. Further, the feed rate has more influence on cutting forces as compared to speed and nose radius. In addition, the minimum quantity lubrication (MQL) of vegetable oil has lowered the cutting forces appreciably compared to dry machining.

Abstract: This titanium material is very difficult to machine due to its low thermal conductivity resulting in heat generated when machining accumulates in the cutting zone. This causes the thermal effect to be absorbed in the drill tool so that the tool wears out quickly which affects the quality of the hole. This study aims to examine the effect of tool wear on the cutting force of hole quality under dry machining conditions and machining using the MQL method. The cutting force resulting from the process of drilling holes using MQL is smaller than drilling in dry conditions. The larger the feed (f), the greater the cutting force (N) that is generated during the drilling process in dry conditions and MQL conditions. The greater the cutting speed (v) used during the drilling process, the lower the cutting force generated

Abstract: This paper presents a prediction of cutting temperature in turning process, using a continuous cutting model of Johnson-Cook (J-C). An method to predict the temperature distribution in orthogonal cutting is based on the constituent model of various material and the mechanics of their cutting process. In this method, the average temperature at the primary shear zone (PSZ) and the secondary shear zone (SSZ) were determined for various materials, based on a constitutive model and a chip-formation model using measurements of cutting force and chip thicknes. The J-C model constants were taken from Hopkinson pressure bar tests. Cutting conditions, cutting forces and chip thickness were used to predict shear stress. Experimental cutting heat results with the same cutting parameters using the minimum lubrication method (MQL) were recorded through the Testo-871 thermal camera. The thermal distribution results between the two methods has a difference in value, as well as distribution. From the difference, we have analyzed some of the causes, finding the effect of the minimum quantity lubrication parameters on the difference.

Abstract: In this paper, experiments are conducted on drilling AISI 316L Austenitic Stainless Steel material using minimum quantity lubrication technique under formulated environmental friendly Pongam oil as cutting fluid. Cutting torque, Thrust force and Surface roughness and Chip formation are studied for the evaluation. The experimental results show that, the Cutting torque is dropped by 36 % under modified Pongam oil as cutting oil, compared to mineral oil base cutting fluid. About 34 % drop in Thrust force and Surface roughness values are noticed under formulated Pongam oil. Further, spiral and continuous form chips are seen under vegetable oil mode of lubrication compared discontinues spiral form under mineral oil based cutting fluid.

Abstract: This paper presents a study on minimum quantity lubrication wherein the metal working fluid is injected individually at multiple points in cutting zone, namely, rake face, back of chip and at flank face. A special attachment is developed for injecting aerosol at all possible combinations of one, two, or three forgoing points of injection. A case study on machining of Ti-6Al-4V showing effect of injection schemes on cutting force and surface roughness is presented. Comparison of multi-point injection with dry and flood cooling indicates reduction in cutting force and surface roughness while using different combinations of fluid injection.

Abstract: The prime rationale for designers to choose titanium in their designs for aerospace applications is its relative low weight for a given strength level and its relative resistance to high temperature. Excellent biocompatibility makes titanium as ideal material for many biomedical applications. Even though the titanium products are either sintered or cast into required shape, there is a need for machining in order to produce intricate shapes. However machining of titanium alloys poses many serious problems owing to the reactivity of titanium at high cutting temperatures and rapid tool wear. An alternative method to overcome this is by reducing the cutting zone temperature. This can be achieved by the addition of solid lubricants to regular cutting liquids and using it as minimum quantity lubrication (MQL) strategy. In this study, hexagonal boron nitride (hBN) powder with different concentrations (5, 10, 15 wt %) was mixed with water and used as a lubricant. Turning experiments were performed with TiAlN coated Tungsten carbide insert for a constant speed and variable feed rates. For comparison purpose, machining was carried out under dry conditions. Results indicate that the cutting zone temperature reduced drastically on addition of solid lubricant hBN with water. MQL conditions showed that cutting zone temperature decreased by several folds when compared to dry machining. However there was no significant decrease in temperature between 10 and 15 wt% hBN additions which indicates that 10% hBN addition proves to be optimal. This type of machining thereby paves way for sustainable manufacturing.

Abstract: This paper discusses the cutting temperature and cutting force in end milling difficult-to-cut materials cooled with several types of mists and low-temperature air. The cutting tool was a throwaway end mill with a carbide tip coated with titanium aluminum nitride. The Ti-6Al-4V titanium alloy and AISI D2 hardened steel were used as workpieces. The tool flank temperature and cutting force were measured simultaneously during side milling. The temperature was measured using a two-color pyrometer with an optical fiber. Oil mist and water mist from a mist generator were supplied to the cutting point along with cold air at approximately -27 °C. Compared with dry cutting, the cooling effects of supplying an oil mist and/or cold air were less than for other supply conditions in titanium alloy cutting. However, when water mist was added, the tool flank temperature clearly decreased. The cutting force increased for cases that included water mist. The adhesion of the titanium alloy to the cutting edge of the worn tool was significantly suppressed by supplying water and oil mist with cold air. Tool flank wear also decreased under those lubrication conditions.