Search Results (204)

The presence of a minimum quantity lubrication (MQL) under the conditions of a burnishing process can contribute to an improvement in the process performance by reducing the heights of the resulting surface asperities, by decreasing the temperature values, and by diminishing the size of the burnishing force components. On the other hand, there are situations in which it is possible to increase the service life of the parts made of EN AW-2007 aluminum alloy by applying a burnishing process. To verify how the results of applying a burnishing process applied to cylindrical specimens in the aluminum alloy when using and not using a minimum quantity lubrication, an experimental research based on a planned variation between certain limits of the values of the peripheral speed and the feed rate has been conceived and materialized. The experimental results were processed mathematically. It has been found that by using the minimum quantity of mineral oil type Valona MS7023 HC, it was possible to reduce the value of the Sa roughness parameter by up to 18%, a decrease in temperature by about 20 °C, and the size of the burnishing force by up to 45%. Full article

The present study aims to investigate the effects of cutting parameters (cutting speed, Vc: 60–90–120 m/min; feed rate, f: 0.055–0.085–0.115 mm/rev), cutting tool coatings (CVD: TiN/TiCN/Al₂O₃ and PVD: TiAlN), and machining conditions (dry, air, and MQL) on cutting force (Fc), specific energy consumption (SEC), surface roughness (Ra), cutting temperature (T), and tool wear (Vb) during the milling of Ti6Al4V alloy. As a result, it was observed that all machining tests conducted with the Al₂O₃-coated cutting tool showed improvements of 4.7%, 10.75%, 3.8%, and 6.3% in Fc, SEC, Ra, and T, respectively, compared to the tests performed with the TiAlN-coated cutting tool. Under dry machining conditions, the average Fc, SEC, Ra, and T values were 302.82 N, 4.88 j/mm³, 0.653 µm, and 241.06 °C, respectively. Compared to dry machining conditions, the air and MQL machining conditions demonstrated improvements in the average Fc by 5.15% and 6.3%, SEC by 10.27% and 17.79%, Ra by 6.23% and 11.17%, and T by 8.9% and 19.68%, respectively. The lowest Fc and Ra values for the Al₂O₃-coated cutting tool were measured at 228.33 N and 0.402 µm, respectively, under the MQL machining condition, at a cutting speed of 120 m/min and a feed rate of 0.055 mm/rev. The lowest SEC value (2.694 J/mm³) was also obtained using the Al₂O₃-coated tool under MQL conditions at a cutting speed of 120 m/min and a feed rate of 0.115 mm/rev. Similarly, the lowest cutting temperature (129 °C) was achieved with the Al₂O₃-coated tool under MQL conditions at a cutting speed of 60 m/min and a feed rate of 0.055 mm/rev. The wear performance of the Al₂O₃-coated cutting tool was observed to be superior to that of the TiAlN-coated tool. Full article

The increasing use of carbon fiber reinforced polymer (CFRP) composites in industries such as aerospace, due to its high strength-to-weight ratio, durability, and resistance to corrosion has led to a growing demand for more efficient machining processes. However, the multilayered structure of CFRP composites, composed of densely packed fibers, presents significant challenges during machining. Additionally, when cutting fluids are used to improve effective cooling and lubrication, the material tends to absorb the fluid, causing damage and leading to problem of weaking of composite structure. To address these issues, this study compares ultrasonic-assisted drilling (UAD) and minimum quantity lubrication (MQL) techniques with conventional drilling (CD) and dry cutting to improve the performance of CFRP composite drilling. The results show that using UAD and MQL together reduced thrust force by up to 27%, improved surface roughness inside the holes by up to 31%, reduced improved hole diameter, cylindricity, roundness, and delamination. Full article

In today’s industrial applications, cutting fluids have attained prime importance due to their all-round features, including increase of tool life by lubrication of the tool at the tool–workpiece interface. This study compares the effects of mango seed oil and pongamia oil on cutting force and surface morphology during the turning of AISI 304 steel. The design of experiments was applied using Taguchi’s method with an L9 array of experiments. During the experiment, it was discovered that mango seed and pongamia-based cutting fluid exhibited the lowest contact angles of 22.1° and 24.4°, respectively, at a 97:3 volumetric concentration of deionized water and eco-friendly oil. The use of mango seed oil as a cutting fluid with MQL (Minimum Quantity Lubrication) resulted in the lowest surface roughness of 0.809 µm, compared to 0.921 µm with pongamia-based cutting fluid. The cutting force was reduced by a maximum of 28.68% using mango seed-based cutting fluid, compared to pongamia-based cutting fluid. ANOVA analysis revealed that feed rate had the maximum influence on the optimization of output parameters for mango seed cutting fluid. For pongamia-based cutting fluid, feed rate had the maximum influence on cutting force, while the depth of cut had the strongest influence on surface roughness. Full article

This study explores the machinability of Incoloy 800HT (high temperature) under a sustainable lubrication approach, employing a twin-nozzle minimum quantity lubrication (MQL) system with groundnut oil as a green cutting fluid. The evaluation focuses on key performance indicators, including surface roughness, tool flank wear, power consumption, carbon emissions, and chip morphology. Groundnut oil, a biodegradable and nontoxic lubricant, was chosen to enhance environmental compatibility while maintaining effective cutting performance. The Taguchi L₁₆ orthogonal array (three factors and four levels) was utilized to conduct experimental trials to analyze machining characteristics. The best surface quality (surface roughness, Ra = 0.514 µm) was obtained at the lowest depth of cut (0.2 mm), modest feed (0.1 mm/rev), and moderate cutting speed (160 m/min). The higher ranges of flank wear are found under higher cutting speed conditions (320 and 240 m/min), while lower wear values (<0.09 mm) were observed under lower speed conditions (80 and 160 m/min). An entropy-integrated multi-response optimization using the MOORA (multi-objective optimization based on ratio analysis) method was employed to identify optimal machining parameters, considering the trade-offs among multiple conflicting objectives. The entropy method was used to assign weights to each response. The obtained optimal conditions are as follows: cutting speed = 160 m/min, feed = 0.1 mm/rev, and depth of cut = 0.2 mm. Optimized outcomes suggest that this green machining strategy offers a viable alternative for sustainable manufacturing of difficult-to-machine alloys like Incoloy 800 HT. Full article

Nickel-based superalloy Hastelloy C276 is widely used in high-performance industries due to its strength, corrosion resistance, and thermal stability. However, these same properties pose substantial challenges in machining, resulting in high tool wear, surface defects, and dimensional inaccuracies. This study investigates methods to enhance machining performance and surface quality by evaluating the tribological behavior of TiSiN/TiAlN-coated carbide inserts under six cooling and lubrication conditions: dry, MQL with coconut oil, Cryo-LN₂, Cryo-LCO₂, MQL–Cryo-LN₂, and MQL–Cryo-LCO₂. Open-slot finishing was performed at constant cutting parameters, and key indicators such as cutting zone temperature, tool wear, surface roughness, chip morphology, and microhardness were analyzed. The hybrid MQL–Cryo-LN₂ approach significantly outperformed other methods, reducing cutting zone temperature, tool wear, and surface roughness by 116.4%, 94.34%, and 76.11%, respectively, compared to dry machining. SEM and EDS analyses confirmed abrasive, oxidative, and adhesive wear as the dominant mechanisms. The MQL–Cryo-LN₂ strategy also lowered microhardness, in contrast to a 39.7% increase observed under dry conditions. These findings highlight the superior performance of hybrid MQL–Cryo-LN₂ in improving machinability, offering a promising solution for precision-driven applications. Full article

The widespread environmental dissemination of imidazole compounds necessitates robust analytical monitoring tools. This study developed a novel isotope-labeled surrogate-based high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) method for the simultaneous determination of 21 imidazoles in water, sediment, and soil. The optimized SPE protocol using Oasis HLB cartridges achieved high recoveries, with chromatographic separation completed in 25 min. Six isotope-labeled standards effectively corrected matrix effects (−57% to 8%), yielding MQLs < 1.0 ng·L⁻¹ (water) and <1.0 μg·kg⁻¹ (sediment/soil). Validation confirmed linearity (R² > 0.995), accuracy (60–120% recovery for 20/21 analytes), and precision (relative standard deviation, RSD < 15%). Its application in Jiulong River revealed significant contamination, detecting eight imidazoles in both water (up to 49.29 ng·L⁻¹) and sediment (up to 24.01 μg·kg⁻¹). This standardized tool enables routine monitoring of pharmaceutical residues across environmental compartments, supporting regulatory frameworks. Full article

Properly refrigerating hard-to-cut alloys during grinding is key to achieve high quality, strict tolerances, and good surface finishing. Nonetheless, literature about the influence of cooling-lubrication conditions (CLCs) on dimensional accuracy of ground components is still scarce. Thus, this work aims to evaluate surface quality, grinding power, and dimensional accuracy of Inconel 718 workpieces after grinding with silicon carbide grinding wheel at different grinding conditions. Four different CLCs were tested: flood, minimum quantity of lubrication (MQL) without graphene, and with multilayer graphene (MG) at two distinct concentrations: 0.05 and 0.10 wt.%. Different radial depths of cut values were also tested. The results showed that the material’s removed height increased with radial depth of cut, leading to coarse tolerance (IT) grades. Machining with the MQL WG resulted in higher dimensional precision with an IT grade varying between IT6 and IT7, followed by MQL MG 0.10% (IT7), MQL MG 0.05% (IT7-IT8), and flood (IT8). The lower tolerances achieved with MG were attributed to the lowering in the friction coefficient of the workpiece material sliding through the abrasive grits with no material removal (micro-plowing mechanism), thereby reducing grinding power and the removed height in comparison to the other CLC tested. Full article

In the context of sustainable manufacturing practices, minimum quantity lubrication (MQL) has been extensively employed in machining operations involving hard-to-cut materials. While substantial experimental and numerical investigations on MQL-assisted machining have been conducted, existing simulation approaches remain inadequate for modeling the dynamic flow field variations inherent to MQL processes, significantly compromising the predictive reliability of current models. This study introduced an innovative bidirectional iterative coupling framework integrating finite element (FE) analysis and computational fluid dynamics (CFD) to enhance simulation accuracy. Since fluid flow characteristics critically influence tribological and thermal management at the tool–workpiece interface during machining, CFD simulations were initially performed to evaluate how MQL parameters govern fluid flow behavior. Subsequently, an integrated FE-CFD modeling approach was developed to simulate Ti-6Al-4V alloy turning under MQL conditions with varying feed rates. The novel methodology involved transferring thermal flux data from FE simulations to CFD’s heat source domain, followed by incorporating CFD-derived convective heat transfer coefficients back into FE computations. This repetitive feedback process continued until the thermal exchange parameters reached convergence. Validation experiments demonstrated that the proposed method achieved improved alignment between the simulated and experimental results for both cutting temperature profiles and principal force components across different feed conditions, confirming the enhanced predictive capability of this coupled simulation strategy. Full article

The widespread use of mineral cutting fluids in metalworking poses challenges due to their poor wettability, toxicity, and non-biodegradability. This study explores cactus oil-based nanofluids as sustainable alternatives for metal cutting applications. Samples of cactus oil are prepared in plain form and with 0.025 wt.%, 0.05 wt.%, and 0.1 wt.% activated carbon nanoparticles (ACNPs) from recycled plastic waste. Plain cactus oil exhibited a 34% improvement in wettability over commercial soluble oil, further enhanced by 60% with 0.05 wt.% ACNPs. Cactus oil displayed consistent Newtonian behavior with a high viscosity index (283), outperforming mineral-based cutting fluid in thermal stability. The addition of ACNPs enhanced the dynamic viscosity by 108–130% across the temperature range of 40–100 °C. The presence of nano-additives reduced the friction coefficient in the boundary lubrication zone by a maximum reduction of 32% for CO2 compared to plain cactus oil. The physical and rheological results translated directly to the observed improvements in surface finish and tool wear during machining operations on H13 steel. Cactus oil with 0.05 wt.% ACNP outperformed conventional fluids, reducing surface roughness by 35% and flank wear by 57% compared to dry. This work establishes cactus oil-based nanofluids as a sustainable alternative, combining recycled waste-derived additives and non-edible feedstock for greener manufacturing. Full article

Nitrosamines (NAs) are toxic compounds associated with disinfection processes. Human exposure can occur through the hydraulic hoses and seals that are in contact with drinking water. This study develops and validates a chromatographic method to quantify 11 NAs in water leachates from four organic materials. The method is based on liquid–liquid extraction (LLE) followed by gas chromatography coupled with mass spectrometry (GC-MS). The method was validated by the application of several statistical tests, namely, linearity/working range, precision, trueness, and recovery tests. The GC-MS method showed a good linear range for all NAs with coefficients of determination (r²) higher than 0.9989, coefficients of variation of the method (CVm) lower than 2.5%, and PG < F (0.05; 1; N-3). The working range varies between 10 µg/L and 386.7 µg/L. The GC-MS method showed good precision under repeatability and reproducibility conditions with a relative standard deviation (RSD) lower than 12% and 10%, respectively. The GC-MS showed good trueness with a relative error lower than 20%. Matrix effects were significant, with recovery (Rec) values between 47% and 125% and an RSD lower than 20%. The limit of detection (LOD) and quantification (LOQ) ranged between 0.71 µg/L and 8.9 µg/L and between 2.3 µg/L and 29.8 µg/L, respectively. The method quantification limits (MQL) ranged from 0.0045 µg/L to 0.0378 µg/L. The sum of the MQL (0.2 µg/L) is lower than the reference limit of 0.3 µg/L for NAs in the leachates from the migration tests. Four organic materials were subjected to migration tests with demineralized and chlorinated water to assess their suitability for the water supply system. These materials met the NA specifications for use in the water network. Full article

Hardox 500 is a special low-alloy, martensitic steel possessing extraordinary wear resistance, high hardness, and high ductility; thus, it has been widely used in many industrial applications. Nevertheless, this type of steel has a low machinability and is grouped among the difficult-to-machine materials. Hence, this paper’s objective was to study its hard milling performance under minimum quantity cooling lubrication (MQCL) conditions using an Al₂O₃/MoS₂ hybrid nano cutting oil. The Box–Behnken response surface methodology was used to investigate the effects of the nanoparticle concentration (NC), cutting speed (v), and feed rate (f) on the total cutting force F and cutting force coefficient F_y/F_z. The obtained results indicate that the cutting efficiency of Hardox 500 steel was improved thanks to the enhancement in cooling lubrication from the MQCL using the Al₂O₃/MoS₂ hybrid nano cutting oil. The applicability of vegetable oil and coated carbide inserts is thus extended to the hard milling of difficult-to-cut materials. Moreover, the provision of the appropriate ranges and optimal set of investigated variables obtained in this paper will be useful guides for technologists and further studies. Concretely, NC = 0.5–0.7%, v = 110–115 m/min, and f = 0.08–0.10 mm/tooth are the optimal set for the total cutting force F, while NC = 0.5%, v = 138–140 m/min, and f = 0.08–0.09 mm/tooth are suggested for the cutting force coefficient F_y/F_z. Full article

Inconel 617 is a nickel-based superalloy that is a primary candidate for use in next-generation nuclear applications such as the Gen IV Molten Salt Reactor (MSR) and Very-High-Temperature Reactor (VHTR) due to its corrosion and oxidation resistance and high strength in elevated temperatures. However, Inconel 617 machinability is poor due to its hardness and tendency to work harden during manufacturing. While the machinability of its sister grade, Inconel 718, has been widely studied and understood due to its applications in aerospace, there is a lack of knowledge regarding the behaviour of Inconel 617 in machining. To address this gap, this paper investigates the influence of cutting parameters in the turning of Inconel 617 and compares the impact of Minimum Quantity Lubrication (MQL) turning against conventional coolant. This investigation was performed through three distinct studies: Study A compared the performance of commercial coatings, Study B investigated the influence of cutting parameters on the surface finish, and Study C compared the performance of MQL to flood coolant. This work demonstrated that AlTiN coatings performed the best and doubled the tool life of a standard tungsten carbide insert compared to its uncoated form. Additionally, the feed rate had the largest impact on the surface roughness, especially at high feeds, with the best surface quality found at the lowest feed rate of 0.075 mm/rev. The utilization of MQL had mixed results compared to a conventional flood coolant in the machining of Inconel 617. Surface finish was improved as high as 47% under MQL conditions compared to the flood coolant; however, work hardening at the surface was also shown to increase by 10–20%. Understanding this, it is possible that MQL can completely remove the need for a conventional coolant in the machining of Inconel 617 components for the manufacturing of next-generation reactors. Full article

This study investigates the machining performance of AZ91D magnesium alloy under three different cooling environments: dry, minimum quantity lubrication (MQL), and nano-reinforced MQL (NanoMQL) with multi-walled carbon nanotubes. Turning experiments were conducted on a CNC lathe with systematically varied cutting parameters, including cutting speed (150–450 m/min), feed rate (0.05–0.2 mm/rev), and depth of cut (0.5–2 mm). The machining performance was evaluated through cutting force measurements, surface roughness analysis, and tool wear examination using SEM. The results demonstrate that the NanoMQL environment significantly outperforms both dry and conventional MQL conditions, providing a 42.2% improvement in surface quality compared to dry machining and a 33.6% improvement over conventional MQL. Cutting forces were predominantly influenced by the depth of cut and the feed rate, while cutting speed showed variable effects. SEM analysis revealed that the NanoMQL environment substantially reduced built-up edge formation and flank wear, particularly under aggressive cutting conditions. The superior performance of the NanoMQL environment is attributed to the enhanced thermal conductivity and lubrication properties of carbon nanotubes, which form a protective tribofilm at the tool–workpiece interface. This study provides valuable insights for optimizing the machining parameters of AZ91D magnesium alloy in industrial applications, particularly where high surface quality and tool longevity are required. Full article

Fluorescent brighteners (FBs) are a class of chemicals extensively used in industrial and consumer products. Their environmental occurrences and potential health risks have raised significant concerns. However, the lack of analytical methods for FBs in human samples has hindered the accurate assessment of internal exposure levels. Addressing this gap, this study developed and validated a novel method for the simultaneous determination of 13 FBs at trace levels in human plasma using solid-phase extraction combined with HPLC-MS/MS. The method employed EMR-Lipid SPE columns, which can selectively adsorb phospholipids for plasma sample pre-treatment. Detection was achieved through positive ion electrospray ionization (ESI) in multiple reaction monitoring (MRM) modes. The results showed that all 13 FBs exhibited good linearity within their respective ranges, with correlation coefficients (R²) greater than 0.992. The method quantitation limits (MQLs) of the FBs ranged from 0.012 to 0.348 ng/mL, and the spiked recovery rates ranged from 61% to 98%. The method was successfully applied to analyze 10 adult plasma samples, detecting 10 FBs with total concentrations ranging from 0.221 to 0.684 ng/mL. This study provides a reliable analytical method for determining FBs in human plasma, providing a basis for further research on human internal exposure to FBs and associated health risk assessments. Full article