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The LM24–7.5ZrB₂–2.5FA hybrid composite presents machining difficulties as it has excellent durability and low-temperature conductivity, making it challenging to machine using standard methods. In spite of this aspect, Electrical Discharge Machining (EDM) is well-suited for machined materials made of aluminum alloys, including LM24–7.5ZrB₂–2.5FA. LM24 aluminum alloy-based hybrid composite prepared using 7.5wt% of zirconium diboride (ZrB₂) and 2.5wt% of Fly Ash (FA) by stir casting route. This study explores the machinability of the hybrid composite and the primary goal is to establish a connection between the process variable’s key efficiency indicators, which include Material Removal Rate (MRR), Surface Roughness (SR), and Tool Wear Rate (TWR), which collectively reflect dimensional accuracy and machining efficiency. The experimentation involves three adjustable process parameters, namely pulse current (I), pulse-on time ($T_{\text{on}}$), and pulse-off time ($T_{\text{off}}$). These variables are subjected to variation, and a total of 20 experimental runs are set up utilizing the Response Surface Methodology (RSM) and a full-factorial Central Composite Design (CCD). Analysis of Variance (ANOVA) is employed to determine which operating variables substantially influence performance characteristics. The analysis reveals that current has a strong influence on MRR, SR, and TWR by 49.5%, 37.7%, and 36.1%, respectively, followed by pulse-on time and pulse-off time. The developed quadratic regression models for MRR, SR, and TWR demonstrated good performance in predicting the responses, as evidenced by the $R^2$ values of 0.9030, 0.9890, and 0.9302 obtained from ANOVA results.

The demand for precision machining in high-strength materials has led to increased interest in understanding the electro-discharge machining (EDM) behavior of welded joints in industrial applications. This study explores the effects of key EDM parameters, such as electrode material, peak current, and pulse duration, on AISI 1541H welded joints. It evaluates the material removal rate (MRR), tool wear rate (TWR), surface roughness (SR), and microstructure, revealing important correlations between EDM settings and the quality of machined surfaces. The study investigates the machining characteristics of oxy-acetylene gas (OAG) and tungsten-inert gas (TIG) welded samples across the fusion zone (FZ), heat-affected zone (HAZ), and unaffected zone (UAZ). For the OAG-welded sample, MRR in the FZ was 15.077mg/min which is less than the MRR of HAZ, and UAZ. It was fine-grain structure has a high MRR in comparison to Coarse grain. Whereas, TWR was 0.22mg/min, 0.32mg/min, and 0.185mg/min in the FZ, HAZ and UAZ respectively. SR values were found Lowest in UAZ at 7.11$\mu$m, and SR was reported at 8.33$\mu$m in FZ, and 7.32$\mu$m in HAZ. Measured microhardness values were 196 HV0.5 in FZ which is 6.2% higher than the microhardness of HAZ. Similar trends were observed in the TIG welded sample, where the MRR was 17.113mg/min (FZ), 17.436mg/min (HAZ), and 17.811mg/min in UAZ. The study reveals that TIG-welded joints outperform OAG joints in terms of machining performance, material removal rates (MRRs), hardness, and surface finish due to lower porosity and better grain distribution whereas the OAG process shows microporosity due to shielding limitations.

In this study, the effects of low-frequency vibrations on machining SKD61 steel workpiece in electrical discharge machining (EDM) with titanium powder-mixed dielectric fluid were investigated. The results showed that the vibrations incorporated into the workpiece in powder-mixed EDM (PMEDM) led to significant improvement in machining efficiency. The material removal rate had the maximum increase of 141.7% with 70.2% of lower electrode wear rate and 69.9% of lower surface roughness. Hence, it is proved that the effectiveness of vibration in PMEDM can be improved.

To further clarify the effect of the polishing slurry dispersant on the chemical mechanical polishing (CMP) performance of 304 stainless steel, a series of tests were carried out. The correlation between the material removal rate (MRR), surface roughness of 304 stainless steel, dispersant composition, and their content was investigated under two kinds of polishing slurry (hydrogen peroxide oxidant and ferric chloride oxidant) conditions. The experimental results indicated that the MRR and surface roughness of 304 stainless steel arrived at the maximum when the content of sodium hexametaphosphate dispersant was 1.2% (wt) under the hydrogen peroxide–oxalic acid polishing slurry condition. The values of MRR and surface roughness were 146 nm/min and 10 nm, respectively. The MRR and surface roughness of 304 stainless also reached the maximum value as the content of the propanetriol dispersant was 1.2% (wt) under the ferric chloride–oxalic acid polishing slurry condition. However, the values of MRR and surface roughness were 457 nm/min and 22 nm, respectively. Therefore, sodium hexametaphosphate was recommended as the dispersant of hydrogen peroxide–oxalic acid polishing, and propanetriol was recommended as the dispersant of ferric chloride–oxalic acid polishing slurry condition, according to the above analysis. This study lays a theoretical foundation for the improvement of 304 stainless steel CMP performance.

The SiC single-crystal substrate with ultrasmooth and damage-free properties has potential applications in the field of optoelectronics and microelectronics. Lapping is one of the important processes for ultraprecision machining of the SiC single-crystal substrate. The lapping quality has an important impact on the surface quality, processing time, processing cost and processing efficiency of the subsequent chemical mechanical polishing (CMP) of the SiC single-crystal substrate. In this paper, four kinds of lapping pastes with different ingredients were prepared. The tribochemical action and mechanism of the oxidant in the lapping paste were studied. The results show that NaOH can be used as an oxidant for the tribochemical mechanical lapping of the SiC single crystal. Under the catalysis of iron oxide and frictional force, the tribochemical reaction between the SiC single-crystal substrate and the oxidant NaOH occurred and the silicon oxides (such as SiO${}_2)$, gaseous carbon oxides and other reactants were produced. The surface energy of the SiC substrate was reduced and the material removal rate was improved effectively. These results can provide a reference for further research on the mechanism of tribochemical mechanical lapping.

The exploration of Electrical Discharge Machining (EDM) with coated electrodes represents a relatively novel research avenue, thereby yielding limited published research outcomes. The choice of coating material plays a pivotal role in the EDM machining process, and alterations in coating materials can directly influence the adjustment of technological parameters in EDM. Consequently, research dedicated to optimizing these technological parameters for EDM employing coated electrodes is of paramount importance, and it promises to advance the practical implementation of this cutting-edge technique. In this study, we systematically investigate the technological parameters for EDM employing a copper-coated aluminum electrode in the context of Ti-6Al-4V machining. Our research outcomes are framed within a multi-objective optimization paradigm, with a focus on Material Removal Rate (MRR) and Surface Roughness (SR) as vital quality indicators. To address the intricate multi-objective optimization challenge, we have harnessed the combined power of the Taguchi methodology and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). The amalgamation of these techniques enables us to navigate the complexities of EDM parameter optimization effectively. Our findings reveal that the most favorable process parameters entail a configuration of $U=40$V, $I=40$ A, $T_{\mathrm{\text{on}}}=1000$$\mu$s, resulting in an MRR of 0.028mg/min and an SR of 7.56$\mu$m. These optimized parameters exemplify a substantial enhancement in machining efficiency and surface quality when utilizing coated electrodes. Moreover, our study scrutinizes the quality of the machined surface under optimal conditions with coated electrodes. We employ the TOPSIS method as a proficient solution for this endeavor, offering a straightforward approach to this intricate calculation process.

Long tool life and high material removal rate (MRR) are the two essential requirements in rough cutting of materials. The rapid rate of the flank wear propagation in machining of nickel-based superalloys has induced the utilization of low cutting parameters when the goal was set to maximize the tool life based on the machining time or cutting length. However, this method may not provide an effective rate for the material being cut. This work presents two mathematical models to find the optimum cutting parameters results for the minimum flank wear and maximum MRR. Experimental tests were carried out based on the central composite design (CCD) in rough cutting of Inconel 625 by using TiAlN-coated insert. Maximum flank wear was measured to determine the tool wear propagation. The wear mechanisms which contribute in the tool wear were analyzed by using scanning electron microscope (SEM) to evaluate the effects of cutting parameters on the flank wear propagation. The results showed that cutting speed and depth of cut had the most significant effect on the tool wear. However, optimum cutting condition was achieved by reducing the cutting speed when feed rate and depth of cut maintained at the highest level. This was associated to the interaction of cutting speed and depth of cut, and predominant of abrasion and notching at their highest levels, respectively.

As an efficient and fast developing surface finishing technique, polishing processes have been widely used in the machining of aero-engine blisk blade. Since a number of processing input variables will influence surface quality and production time, controlling surface finish and machining efficiency require a carefully designed combination of various processing parameters. Therefore, this paper presented a comprehensive multi-objective parameter optimization method that integrates grey relational analysis (GRA), radial basis function (RBF), as well as firefly algorithm (FA). The purpose is to simultaneously obtain the optimal parameter combination for minimum surface roughness and the greatest material removal rate by optimizing rotational speed, feed rate and polishing force in Ti-6Al-4V blisk blade polishing. The hybrid experiments were carried out by combining the orthogonal experimental design with the single-factor experimental design. GRA was run for converting multi-objective response into the single-objective response. Then, RBF was applied to build the relationship between the grey correlation degree and the control variables. Finally, FA was utilized to obtain the optimal grey correlation degree in the range of control variables. The verification tests showed the highest material removal rate of 5.370mm²/s and surface quality of 0.374$\mu$m have been successfully achieved.

This study deals with the investigation on the effect of Electrical Discharge Machining (EDM) parameters during machining of hybrid composite (Al 7075/TiC/B₄C). The optimum process parameters of die sinking EDM like pulse current, pulse duration and gap voltage on metal removal rate, tool wear rate and surface finish were investigated. Full factorial experimental design was selected for experiments. Analysis of variance was employed to study the influence of process parameters and their interactions on response variables. Among the process parameters considered, it was observed that the pulse current was found to be more influential in affecting MRR, TWR and SR. The other parameters have little effect on the response variable. Multi-objective optimization study was also performed using genetic algorithm to find the optimum parameter setting for controversial objective function combination such as high MRR and low SR and High MRR and low TWR. Scanning electron microscope study was performed to study the surface characteristics.

In this paper, the effect of cutting parameters during micromilling on surface finish and material removal rate is presented. Inconel 718 alloy and high-speed steel micro end mill are used as work material and cutting tool, respectively. High-speed steel end mill of 1 mm diameter is subjected to cryogenic treatment. Machining studies are performed on Inconel alloy using untreated and cryogenic treated cutters. The milling tests are conducted at three different values of feed rate, cutting speed and depth of cut. Also, tool wear, microstructure and microhardness of different treated and untreated end mill are investigated and discussed in detail. The results showed that cryogenic treatment significantly improved the tool wear. The surface finish produced on machining the work-piece is better with the cryogenic treated tools than when compared with the untreated tools. The material removal rate is better with the cryogenic treated tools than when compared with the untreated tools. Improvement in tool life was up to 53.16% for Inconel 718 material when machined with cryogenically treated micro end mill.

In this study, the effects of experimental parameters on average surface roughness and material removal rate (MRR) were experimentally investigated by machining of AISI 304 stainless steel plates by magnetic abrasive finishing (MAF) method. In the study in which three different abrasive types were used (Al₂O₃, B4C, SiC), the abrasive grain size was changed in two different levels (50 and 80$\mu$m), while the machining time was changed in three different levels (30, 45, 60min). Surface roughness values of finished surfaces were measured by using three-dimensional (3D) optical surface profilometer and surface topographies were created. MRRs were measured with the help of precision scales. The abrasive particles’ condition before and after the MAF process was examined and compared using a scanning electron microscope. As a result of the study, the surface roughness values of plates were reduced from 0.106$\mu$m to 0.028$\mu$m. It was determined that the best parameters in terms of average surface roughness were 60min machining time with 50$\mu$m B4C abrasives, while the best result in terms of MRR was taken in 30min with 50$\mu$m SiC abrasives.

Progressive development in the industrial field leads to the increasing demand for superalloys with enhanced mechanical properties, such as toughness, hardness, ductility, damping strength, tensile strength and improved surface finish. Monel 400, one of such superalloys, with the majority of its application in aerospace and marine fields demands a good super finish. There arises the need for some nonconventional processes like WEDM. This process is more effective to obtain complex shapes to close tolerance. This research focuses on clear understanding of the machining strategies with proper parametric combinations to achieve an improved surface finish, subsequently reducing the time and expense involved in the superfinishing procedure. The surface qualities of the selected samples are validated with the help of roughness profile and topography images. This study has proven that the increasing input current and wire feed rate (WFR) consistently decreases the surface roughness (SR; $R_a)$ of the specimen. This paper also explains the effect of topographic parameters and microstructure over the resulting SR. In addition, the consistent contribution of WFR and input current toward the lower SR is established. The relationship between morphological behavior and parametric deviations is evaluated. A significant correlation found to exist between the rate of wire feed and the height parameters of SR such as $S_{\mathrm{\text{sk}}}$, $S_{\mathrm{\text{ku}}}$, etc.

This study employs Taguchi orthogonal design (L₉) to optimize the machining parameters of electro-discharge machining (EDM). The aluminum matrix composite (AMC) with 16wt.% titanium carbide (TiC) and 4wt.% graphite (Gr) specimen was prepared by stir casting process. This study involves three control parameters with three levels, namely pulse current, voltage and fluid pressure to predict the process response, such as material removal rate (MRR) and surface roughness (SR) of the worn surface. Maximum MRR of 0.1661g/min was attained for 10A, 500V and 15kgf/cm² fluid pressure with corresponding roughness of 11.43$\mu$m and the minimum value of 7.51$\mu$m was observed for 10A, 100V and fluid pressure of 5kgf/cm². A regression model was developed and the effect of control parameters on process responses were determined by analysis of variance (ANOVA). According to ANOVA outcome, the machining parameters which control the process response MRR were determined as voltage (47.94%), pulse current (33.19%) and fluid pressure (17.58%). Similarly, the SR was affected by machining parameters voltage (55.17%), pulse current (22.41%) and flushing pressure (21.47%). The optimum machining parameters were predicted and confirmed by conducting experiments with reasonable error of 2.49% and 2.02% for MRR and SR, respectively. Surface characteristics of the machined AMC was analyzed by scanning electron microscope (SEM) to observe the defects like craters, voids, glued debris and recast layers.

The AA7075 composites reinforced with 3, 6, and 9 volume fractions (vol.%) of ZrB₂ particles have been successfully fabricated using in situ fabrication method. In this technique, the inorganic salts K₂ZrF₆ and KBF₄ were added to the molten aluminum and retained the melting at 900^∘C to form the required vol.% of ZrB₂ particles. The aluminum-reinforced metal matrix composites (MMCs) are commonly known as aluminum matrix composites (AMCs). This work carries the effects of various wire electrical discharge machining (WEDM) input process parameters like pulse-on-time ($T_{\mathrm{\text{on}}}$), pulse-off-time ($T_{\mathrm{\text{off}}}$), wire feed rate (WFR), and gap voltage (GV) on the output responses such as material removal rate (MRR), surface roughness (SR), and Kerf-width ($K_W$) of the fabricated AA7075/(3, 6, and 9) vol.% ZrB₂in situ AMCs. Based on Taguchi’s L9 orthogonal array method, the design of experiments (DoE) was used to carry out the operations on the fabricated AMCs. The optimal level of process parameters was found by the main effects plot for signal-to-noise (S/N) ratio, contour plots, and the analysis of variance (ANOVA). The effect of these process parameters on MRR and SR was analyzed and it is found that the maximum MRR was attained in the optimal parametric combination of GV $=60$V; $T_{\mathrm{\text{on}}}=4$$\mu$s; $T_{\mathrm{\text{off}}}=6$$\mu$s; WFR $=12$mm/s; Reinforcement $=3$ vol.%, and the minimum SR was attained in the optimal parametric combination of GV $=60$V; $T_{\mathrm{\text{on}}}=2$$\mu$s; $T_{\mathrm{\text{off}}}=9$$\mu$s; WFR $=8$mm/s; Reinforcement $=3$ vol.%.

Electrical discharge machining (EDM) is widely applied for machining difficult-to-cut materials in mold and die industries. However, the major limitations associated with the EDM are low productivity and poor surface integrity of the machined surfaces. In recent years, several developments have been applied to overcome such limitations of EDM. Electrical discharge grinding (EDG) is a hybrid machining process that simultaneously involves the spark erosion action of EDM and the mechanical abrasion action of the grinding wheel for the material removal purpose. The rotating motion of the grinding wheel also contributes to the easy removal of debris particles, thereby improving the material removal. It is evident from the literature that the rotating motion of the grinding wheel enhances the flushing mechanism resulting in better performance of the process. This paper aims to present a comprehensive review of the research carried out in EDG, highlighting the result of the experimental, modeling, and optimization techniques applied in this area. Initially, the background of EDM and the need for hybrid EDM processes have been presented. Then, a few hybrid EDM processes have been discussed, addressing their advantages and limitations. Further, the concept of EDG and electrical discharge diamond grinding (EDDG) has been discussed, along with the classification of the EDDG process. Finally, this paper explores the current research status and future research perspective in the area of EDG and EDDG processes.

The machinability of a cutting tool merely depends on cutting temperature, surface finish, and tool life, etc. To investigate the machinability of non-textured plain cutting inserts and micro-textured cutting inserts, various novel micro-textures have been fabricated using a femtosecond laser machine on the rack face of the double-sided square cutting insert without amputating its TiCN coating. The turning operation has been performed on a Titanium Gr 2 rod of diameter 50 mm on a three-jaw self-centered lathe machine. Type of insert, rotational speed, and cutting feed rate are the main parameters with various levels. L27 orthogonal array has been used for the design of experiments. Significant reduction in cutting tool temperature and surface roughness has been observed using micro-textured cutting inserts. The cutting insert with Honeycomb micro-texture gives superior results with a minimum cutting temperature of 210^∘ C and a maximum of 76% improvement in surface finish.

The removal of metal in the form of sludge can be termed an ECM process, having primary salient features consisting of the tool, workpiece, power supply and electrolyte solution. ECM is a potential nontraditional machining process that includes too many factors contributing to process performance. Therefore, obtaining optimal factor combinations for higher efficiency is complex. In this research work, machining parameters are voltage, powder concentration and electrolyte concentration, based on which material removal rate (MRR) and surface roughness (SR) are derived. Regression analysis, signal-to-noise ratios and analysis of variance (ANOVA) are performed to determine the optimal levels and to examine the effects of machining parameters on MRR and SR. The results derived from the experiments noticed that the MRR decreases when the voltage level is increased and surface roughness decreases for the applied voltage. In case of an increase in powder concentration, MRR decreases from range 4 to 6 and further reduces to 6–8. In case of SR, it additionally decreases on the maximum level of powder concentration. In electrolyte concentration, the MRR decreases on the increment of electrolyte and increases after a short period of time; simultaneously SR is increased from range value 10–20 and decreased with a maximum level 20–30 of NaCl solution. A comparison of MOORA-PCA and TOPSIS-PCA demonstrates the superiority of TOPSIS over MOORA technique. Statistical results (95% confidence level) indicate that the voltage, powder concentration, and electrolyte concentration affect the surface roughness by 69.50%, 8.67% and 14.59% in the electrochemical machining of d3 die steel. Therefore, the optimum combination of process parameters corresponding to voltage: 45V, powder concentration: 4g/L, and electrolyte concentration: 10NaCl/L, respectively, were found to yield the desired result. The prediction accuracy of the TOPSIS-PCA hybrid approach model is found better than MOORA-PCA technique.

Knee joint surgery for artificial joint replacement is common in orthopedic surgeries. In this operation, there is a need to prepare the surface of the cortical bone for mounting the artificial joint. Therefore, milling process is frequently performed. Since the surgeon should be careful not to hurt bone tissue and neurons and also minimize waste of blood, the operation should be performed in the shortest possible time. This study, for the first time, focuses on modeling and optimization of effective parameters of bone milling including cutting speed, feed rate and tool diameter on surface roughness and material removal rate using response surface method. Results showed that in order to achieve maximum surface quality, minimum feed rate, maximum tool diameter and down milling procedure should be selected. On the other hand, the maximum material removal rate coincides with maximum feed rate and tool diameter. Therefore, cutting speed of 3000rpm, feed rate of 50mm/min, tool diameter of 5mm and down milling procedure can satisfy both high surface quality and high material removal rate.

In the present work, an investigation has been made into the electrical discharge machining process during machining of precipitation hardening stainless steel PH17-4. Taguchi method is used to formulate the experimental layout, to analyze the effect of each process parameter on machining characteristics and to predict the optimal choice for each electrical discharge machining process parameters namely, peak current, pulse on time and pulse off time that give up optimal process performance characteristics such as material removal rate, surface roughness, tool wear rate and surface hardness. To identify the significance of parameters on measured response, the analysis of variance has been done. It is found that parameters peak current and pulse on time have the significant affect on material removal rate, surface roughness, tool wear rate and surface hardness. However, parameter pulse off time has significant affect on material removal rate. Confirmation tests are conducted at their respective optimum parametric settings to verify the predicted optimal values of performance characteristics.

Inconel 718 superalloy is widely used in aerospace industries for fabrication of the various components for aircraft engine because of its high strength at elevated temperature. It is an extremely difficult-to-machine material due to its work hardening nature and poor thermal conductivity. Creating micro-holes of high precision in this material is beyond the capability of conventional twist drill due to its low thermal conductivity. Micro-electrical discharge machining (micro-EDM) is a well-established process for the machining of any electrically conductive hard and brittle material, but due to very small feature size and narrow discharge gap, removal of debris becomes difficult, causes arcing and short-circuiting. In order to solve this problem, authors indigenously developed an innovative ultrasonic-assisted micro-EDM setup for workpiece vibration. The machining performance characteristics of Inconel 718 superalloy was studied using the developed setup in sinking configuration in terms of material removal rate (MRR), tool wear rate (TWR) and hole taper ($T_a$) considering the effect of ultrasonic power, gap current, pulse on time and pulse off time. It was observed that higher ultrasonic power was more suitable for higher MRR, lower TWR and $T_a$. It was also found from the results that 3 A gap current at 6$\mu$s pulse on time was appropriate for better MRR and 12$\mu$s pulse on time was more appropriate for low TWR and $T_a$. The scanning electron microscope (SEM) analysis of created micro-holes was also performed with and without ultrasonic vibration to ensure the quality as well as accuracy.