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The Ti-5Al-5V-5Mo-3Cr (Ti-5553) alloy is a relatively novel difficult-to-cut material with limited machinability and tool life analysis available in the literature, and hence requires further investigation. This study focuses on the machining and tribological performance of Ti-5553 under high-speed finish turning (150 m/min, 175 m/min, and 200 m/min) via novel mono/bi-layered PVD-coated WC tools. A base AlTiN coating is used as the reference monolayer coating, with AlCrN, diamond-like ta-C, and TiAlSiN coatings each deposited on top of a base AlTiN coating, totaling four separate coated tools (one monolayer and three bi-layer). Tool life, cutting forces, workpiece surface quality, and tribological chip analysis are among the subjects of investigation in this study. Overall, the AlTiN/AlCrN coated tool outperformed all the other combinations: an improvement of ~19% in terms of tool life in reference to the base AlTiN coating when averaging across the three speeds; lowest surface roughness values: ~0.30, 0.33, and 0.64 µm; as well as the lowest chip back surface roughness values: ~0.80, 0.68, and 0.81 µm at 150, 175, and 200 m/min, respectively. These results indicate that the AlTiN/AlCrN coating is an excellent candidate for industrial applications involving high-speed machining of Ti-5553. [ABSTRACT FROM AUTHOR]

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Dry cutting is an effective method to realize the concept of green cutting today. However, in the process of cutting bearing steel, the high temperatures and high pressures produced by the cutting tool and chip under dry friction seriously affect the machining performance of the tool. Therefore, a bionic microstructure tool based on bionics is proposed to improve the cutting performance and reduce friction by changing the size parameters of the microstructure. On the basis of finite element simulation and cutting tests, the cutting force, surface roughness, and chip shape are used to evaluate the cutting performance. It is found that composite bionic micro-textured tools have a significantly reduced cutting force compared with non-micro-textured tools; composite bionic micro-textured tools lead to a reduction in surface roughness of 10–25%; and composite bionic micro-textured tools are more prone to enhancing the curling and breaking of chips. In addition, with the increase in the microstructure area occupancy, the cutting performance of the tool was also significantly improved. Moreover, it was found that the cutting performance of the tool was improved when the area occupancy of the micro-texture on the front face of the tool was increased. [ABSTRACT FROM AUTHOR]

In the context of satisfying sustainability requirements nowadays, dry machining is one of the ideal strategies to eliminate the environmental and human health burdens of machining processes. In addition, micro-textured cutting tools are used to improve the performance of dry machining processes. Micro-textures reduce the chip-tool contact length and thus reduce friction and heat, which results in fewer cutting forces and temperature. However, the action of micro-cutting of the bottom side of the chip, which is known as derivative cutting, cuts down the gains of using textured tools, where derivative cutting leads to higher cutting forces, heat, and tool wear. This study aimed to investigate the effects of significant texture design parameters (i.e., micro-groove width) when cutting AISI 1045 steel using different machining parameters (i.e., 75 m/min and 150 m/min of cutting velocity, 0.05 and 0.10 mm/rev of feed). Three different textured cutting tool designs were prepared using the laser texturing technique and then utilized in machining experiments. In addition, the measured machining outputs were forces, power consumption, flank wear, and surface roughness. There were no marks for the derivative cutting when using the textured cutting tool with the narrowest micro-grooves according to the obtained microscopical images after the machining tests. In addition, the textured cutting tool, which included the narrowest micro-grooves, showed better performance compared to the non-textured cutting tool and the other textured tool designs in terms of cutting and feed forces, power consumption, flank tool wear, and surface roughness at the used cutting conditions. This confirmed that the careful optimal design of the micro-textured tools can reduce or eliminate the severity of the derivative cutting, and thus improve the overall machining performance. [ABSTRACT FROM AUTHOR]

This article presents an experimental investigation and statistical analysis of the effects of cutting conditions on the machining performance of AISI 1045 steel using a wiper-shaped insert. Experimental findings are used to compare the machining performance obtained using wiper inserts with those obtained using conventional round-nose inserts as recently reported in the literature. In addition, the effects of process conditions, namely cutting speed, feed rate, and depth of cut, are analyzed in order to obtain optimum conditions for both types of inserts. The goal is to achieve the optimal machining outcomes: minimum surface roughness, resultant cutting force, and cutting temperature, but maximum material removal rate. A full factorial design was followed to conduct the experimental trials, while ANOVA was utilized to estimate the effect of each factor on the process responses. A desirability function optimization tool was used to optimize the studied responses. The results reveal that the optimum material removal rate for wiper-shaped inserts is 67% more than that of conventional inserts, while maintaining a 0.7 µm surface roughness value. The superior results obtained with wiper-shaped inserts allow wiper tools to use higher feed rates, resulting in larger material removal rates while obtaining the same surface quality. [ABSTRACT FROM AUTHOR]

Titanium alloys are widely used in aerospace, the military industry, electronics, automotive fields, etc., due to their excellent properties such as low density, high strength, high-temperature resistance, and corrosion resistance. Many components need to be finished precisely after being cut in these applications. In order to achieve high-quality and high-efficiency finishing of titanium alloys, ultrasonic-assisted magnetic abrasive finishing (UAMAF) was introduced in this research. The machining performance for UAMAF of a titanium alloy was studied by experimentally comparing UAMAF and magnetic abrasive finishing (MAF). The results show that the cutting force of UAMAF can reach 2 to 4 times that of MAF, and it decreases rapidly with the increase in the machining gap due to the energy loss of ultrasonic impact in the transmission between magnetic abrasives. The surface roughness of UAMAF can reach about Ra 0.075 μm, which is reduced by about 59% compared with MAF. The main wear type of the magnetic abrasive is that the diamond grits fell off the magnetic abrasive in both UAMAF and MAF. The uniform wear of the magnetic abrasive is realized, and the utilization ratio of the magnetic abrasive is obviously improved in UAMAF. [ABSTRACT FROM AUTHOR]

In machining industries, sustainable production activities are reduced because of the tool wear effect. The machining input parameters are mainly responsible for the effect of flank wear attained in the tool and the workpiece's surface quality. This work aims to determine and predict the machining performances of EN2-BS970/Mild steel by varying the input parameters such as cutting speed (V), feed (F), nose radius (r), and depth of cut (d). The hybrid Deep Convolutional Neural Network-based Manta-Ray Optimization (DCNN-MRO) is used to predict the machining outcomes, and it is performed in Matlab software version 2020a. The input machining parameters are designed by response surface methodology of box behnken design performed in Design-Expert software version 11. The experimented different cutting forces are feed force (Fx), radial force (Fy), cutting force (Fz), and the machining performances are tool flank wear, surface roughness, and Tool chip thickness. In which, the machining input parameter, namely cutting speed effectively influences the turning outcomes. The effect of tool flank wear and surface roughness by varying the cutting forces are also analyzed. The observed optimal surface roughness is 3.105 μ m , tool wear rate is 0.139mm, and tool chip thickness is 0.11mm. The measured outcomes are closer to the predicted outcomes obtained from hybrid DCNN. The average RMSE obtained from the proposed DCNN-MRFO is 0.03, and the non-hybrid DCNN is 0.3. [ABSTRACT FROM AUTHOR]

Anti-abrasion thin-film-coated tool is well known for its enhanced micro machining performances. However, coating increases tool edge radius, which spurs additional ploughing and rubbing. Therefore, selecting appropriate thin-film thickness and suitable abrasion-resistant coating material for micro tool is necessary to reduce friction and size effects together. To meet these objectives, first, single-layer TiAlN coating having various thin-film thicknesses has been deposited on uncoated micro end mills by PVD process. By analyzing the cutting force, surface quality and edge radius of both fresh and worn tools in micro milling of P-20 steel, appropriate thin-film thickness has been found to be ≈ 1 μm. Next, single layer TiN and diamond-like-carbon (DLC) coating of thickness ≈ 1 μm have been coated on uncoated WC tools. Then coefficient of friction (COF) and hardness of all coated and uncoated surfaces are assessed. Finally, the performance of all the coated and uncoated tools have been evaluated analytically and experimentally by analyzing dynamic stability and machinability, respectively. All the coated tools manifested enhancement in performance by uplifting stability limit and reducing tool wear, cutting forces, surface roughness and burr heights compared to the uncoated tool. Owing to the least COF, the DLC-coated tool exhibited the best performance by uplifting stability limit by 23.37% and reducing cutting force, surface roughness and burr height by 27.35%, 67.7%, and 30.58%, respectively. However, for a long machining length (1200 mm), the DLC-coated tool could not exhibit such performance as compared to TiAlN-coated tool due to significant delamination. [ABSTRACT FROM AUTHOR]

Cutting fluids used in the metal machining industry have exerted serious impacts on the environment and human health. In addition, the very high cutting heat and forces in machining-hardened steels have been a growing concern in the metal cutting field. Hence, new, eco-friendly cooling and lubricating techniques are necessary to study and develop. Minimum quantity lubrication (MQL) and minimum quantity cooling lubrication (MQCL) using nano cutting fluids have been proven as alternative solutions for machining difficult-to cut materials while retaining an environmentally friendly characteristic. Accordingly, this paper aims to analyze and evaluate the hard turning efficiency of 90CrSi (60 ÷ 62 HRC) steel using MQL and MQCL conditions, using Al2O3 and MoS2 nano cutting fluids. The 2k-p experimental design and analysis of variance (ANOVA) were used to study the influence of input parameters including fluid type, lubrication method, nanoparticle type, nanoparticle concentration, cutting speed and feed rate on surface roughness. The obtained results showed that the machinability of CNMG120404 TM T9125 carbide tools was improved and the highest machinable hardness was increased from 35 HRC to 60 ÷ 62 HRC (rising by approximately 71.4 ÷ 77.1%) by using the nanofluid MQL and MQCL methods. Furthermore, MQCL gives better performance than MQL, and the Al2O3 nanofluid exhibits the better result in terms of surface roughness values than the MoS2 nanofluid. Feed rate displays the strongest influence on surface roughness, while fluid type, nanoparticle concentration and cutting speed show low impacts. From these results, technical guidance will be provided for further studies using Al2O3 and MoS2 nano cutting fluids for MQL and MQCL methods, as well as their application in machining practice. [ABSTRACT FROM AUTHOR]

Axial ultrasonic vibration-assisted cutting (AUVC) has been proved to have better machining performance compared with conventional cutting methods; however, the effect of numerous and complex influencing factors on machining performance has not been clearly revealed, and a recommended combination of cutting conditions has not been proposed yet, especially for difficult-to-machine material such as Ti6Al4V alloy. This paper focuses on the experimental and theoretical investigation into Ti6Al4V machining performance with AUVC method. First, a retrospective of the separation characteristics of AUVC is provided, and the variable parameter cutting characteristics are demonstrated. The influencing factors on machining performance are classified into four categories: machining parameters, vibration parameters, tool choice, and cooling conditions. The relationship between these factors in terms of their effect on machining performance is established theoretically. Then, it describes experiments to determine the influence of these factors on cutting force, tool life, and surface roughness. For absolute influence, the orders for cutting force, tool life, and surface roughness are respectively cutting depth > amplitude > feed rate > rotation speed, rotation speed > feed rate > amplitude > cutting depth, and feed rate > amplitude > cutting depth > rotation speed. However, for relative influence, the order is unified as amplitude > feed rate > rotation speed > cutting depth. Finally, it suggests a smaller feed rate, larger amplitude, moderate rotation speed, and smaller cutting depth in addition to a WC tool coated with TiAlN and used under HPC cooling condition for optimal performance of AUVC. This recommendation is based on the theoretical analysis and experimental results of cutting force, surface roughness, and tool life. [ABSTRACT FROM AUTHOR]

Machining of CFRP composites is usually described as a challenging process from tool life and surface quality perspectives. To achieve a flawless machined surface at reasonable cutting tool life/cost, an optimum combination of cutting tool material and geometry is the key. The cutting tool angles are of importance as these dictate the cutting mechanism as well as the cutting edge robustness and the introduction of vibration to the machining process opens up new horizons of improvement and stirs further research questions. This article investigates the effect of tools with different geometry possessing different rake angles when used in ultrasonic-assisted edge trimming operation dealing with multidirectional CFRP laminates. A full-factorial experimental design was adopted to analyze the effect of process parameters typically cutting speed, feed rate, rake angle, amplitude, and their interactions. Machining performance indicators were captured which were the cutting forces, tool wear, chip temperature, and surface roughness. The results showed that UAM mode contributed to an increase in the cutting forces, tool wear, and chip temperature compared to the conventional mode. On the other hand, UAM mode improved the quality of the machined surface. Additionally, the ultrasonic mode enhanced the material removal mechanism using a tool with a negative rake angle. [ABSTRACT FROM AUTHOR]

This work presents a novel coolant suitable for different machining processes. The focus of this study is applying superabsorbent coolant (SAC) during milling of hardened H13 steel and evaluating the possibility of utilizing superabsorbent material as a coolant and comparing with dry and flood conditions. The use of SAC is a novel method of semi-dry machining that proves the performance of hydrogels as a coolant and opens a new window for industrial applications. The main purpose besides improving machining performance is that a suitable condition has been provided to use benefits of nanoparticles (higher thermal conductivity and lubricity) safely and prevent distribution of nanoparticles and other chemical additives in the air which can cause serious occupational and environmental problems as well. The results of machining studies indicate that SAC can considerably reduce cutting force, improve surface integrity, and increase tool life. In addition, the friction conditions at the cutting zone have been improved. The results show a lower surface roughness of the chip surface. [ABSTRACT FROM AUTHOR]

In this paper, the evolutions of cutting force, cutting temperature, and surface roughness, and the corresponding machinability in asymmetric up-milling of TC25 alloy are investigated. The results indicated that radial depth of cut generated opposite influence on the cutting force/cutting temperature versus surface roughness. The reason can be accounted as the intertwining of feed marks at low radial depth of cut, and the mechanism of hard cutting at a high radial depth of cut. Moreover, the asymmetry has a significant effect on the machinability in asymmetry up-milling TC25 alloy. Changing the asymmetry, i.e., the radial depth of cut, can alter the machinability while maintain the balanced development of various indexes. The machinability reaches the best when the radial depth of cut is ae = 8 mm. The axial depth of cut and feed per tooth should be selected as large as possible to avoid work hardening and to improve machining efficiency in asymmetric up-milling TC25 alloy. The cutting speed should be controlled within Vc = 100–120 m/min to obtain better machinability. On the basis of this research, it is expected to find optimized milling parameters to realize high efficiency milling of TC25 alloy. [ABSTRACT FROM AUTHOR]

• CMQL was proposed as an eco-friendly alternative to machine the CFRP. • The lubri-cooling mechanisms under different conditions were revealed. • CMQL indicates great potential for the machining of CFRP. Due to the hygroscopicity of CFRP, dry and/or near-dry cutting conditions instead of conventional flood lubrication is recommended for CFRP machining. However, thermal damage, poor surface integrity, and harmful dust occur when machining CFRP under dry conditions. To address the above problems, this paper aims to investigate the machining performance of CFRP laminates under cryogenic-based conditions, which are characterized as cryogenic supercritical carbon dioxide (scCO 2) and vegetable oil-based cryogenic minimum quantity lubrication (CMQL). The milling temperatures, milling forces, surface quality and surface generation mechanism were particularly studied to analyze the effect of cooling category on the milling performance of CFRP under varying cutting parameters. To reveal the underlying mechanisms of performance evolution with different lubri-cooling conditions, the basal tribology and wettability tests were innovatively carried out as a function of lubri-cooling environments. Results indicate that the minimum milling forces, milling temperatures and machined surface roughness were obtained under CMQL condition. Cryogenic cutting operation reduces the cutting temperature, increases the cutting force while improves the surface quality. The mechanism of material removal is significantly different under different tool-fiber angles. This study also demonstrated the feasibility of cryogenic cutting, especially CMQL condition to improve the surface quality during CFRP precision machining. [ABSTRACT FROM AUTHOR]

Nanofluid based lubricants have immense acceptability in sustainable and eco-friendly machining of superalloys – this is due to their superior heat transfer ability. Extreme demands for sustainable manufacturing compelled the manufacturers to avail synergistic benefits with higher machinability and lower carbon footprint on the environment. For that purpose, the performance of an indigenously developed minimum quantity nano-green lubricant is investigated in milling of Inconel 690. Accordingly, nano-silica (vol% varying from 0.5 to 1.5%) was reinforced into palm oil and sprayed into the tool-chip interface through minimum quantity lubrication set up. The milling operations were executed under five different lubricating mediums: dry, minimum quantity palm oil, 0.5% silica deposited palm oil, 1% silica deposited palm oil, and 1.5% silica deposited palm oil. Comparative tool life, surface roughness, resultant cutting force, and cutting temperature were assessed. Subsequently, SEM and EDX images were analyzed to confirm the governing tool wear mechanisms. Experimental data shows that 1% silica deposited palm oil medium performs better concerning all machining responses. Furthermore, a multi-objective response surface methodology (MORSM) confirmed that speed of 88.18 m/min, feed of 0.11 mm/tooth, depth of cut of 0.50 mm, and 1%-MQNGL based lubricating condition are the optimal design parameters to achieve sustainable working environment. • The effect of nano-green lubricants on the machining performances is evaluated. • Wear mechanism of TiAlN/AlCrN coated carbide insert is examined. • A sustainable machining environment is identified using MORSM. [ABSTRACT FROM AUTHOR]

Titanium alloys are difficult-to-cut materials due to their low elastic modulus and poor thermal conductivity. To deepen the understanding of the cutting performance for Ti–6Al–4V under various eco-friendly cooling conditions, surface integrity, cutting forces, and tool wear were comprehensively investigated through cutting experiments implementing three cooling methods, namely, cryogenic gas (CG), minimum quantity lubrication (MQL), and a combination of CG and MQL (CG + MQL), respectively. The results show that the lowest surface roughness (S a = 76.71 nm) was achieved at a low spindle speed under the CG + MQL cooling conditions. This suggests that of the three cooling methods, the CG + MQL hybrid cooling method achieved the highest cooling efficiency. Compared with the MQL cooling method, the CG + MQL cooling method led to more pronounced tool wear and material adhesion due to reduced oil-based lubricity caused by low temperatures. Under the MQL cooling conditions, the elastic recovery of Ti–6Al–4V accelerated the formation of micro-cleavages on the clearance face of the diamond tool. Additionally, the depth of cut was also comparable to the tool edge radius in the micro-scale diamond turning. Compared with the conventional turning of Ti–6Al–4V, this round-edge effect, combined with the adhesion and built-up edge, led to a relatively stronger friction effect, evidenced by an increase in the coefficient of friction from 1.027 to 3.532, and higher specific cutting energy under all the cooling conditions in micro-scale diamond turning. [ABSTRACT FROM AUTHOR]