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Nickel–titanium shape memory alloys (SMAs) are popular due to their usefulness and functional characteristics. The binary NiTi SMA was alloyed with vanadium to improve memory retention properties. In this study, the abrasive aqua jet machining method was adopted to machine the Ni50Ti48V2 ternary SMA to minimize the kerf taper angle (KTA), surface roughness (Ra) of machined Ni50Ti48V2 surface, and enhance the material removal rate (MRR). RSM-BBD optimization using the input variables such as abrasive flow rate (AFR), water jet pressure (PWJ), nozzle traverse speed (VTS), and standoff distance (SFD) predicted that PWJ and SFD highly contributed to MRR, Ra, and KTA responses. Small variation in variation after optimized AWJM conditions, and XRD analysis confirmed no phase changes after AWJM. [ABSTRACT FROM AUTHOR]

In this study, the duplex stainless steel is machined using a wire-cut electrical discharge machining process to overcome the issues of poor finishing, lower dimensional accuracy, and rapid wear of cutting tools in conventional machining processes. The higher rate of material removal and superior finish on the machine surface is dependent on kerf loss, which is expressed as the mean kerf width assessed at certain locations. Nevertheless, this approach is typically not effective in explicating the intricacies of true kerf loss due to the random selection of distinctive points. This work proposes an area-based measuring approach to quantify the kerf loss by taking into account any imperfections on the kerf wall. At the pulse on time of 20 μs and current of 3 A, the machining appears not stable. The pulse on time, current, and voltage of 12 µs, 1 A, and 80 V proved suitable for obtaining excellent dimensional precision. [ABSTRACT FROM AUTHOR]

This study investigates the performance of deep cryogenically treated brass (CuZn25Al5) electrodes in the die-sink EDM process. Two different cryogenic treatment durations, 6 h and 12 h, were applied to 8 mm diameter electrodes, and their effects were compared to untreated electrodes. The machining tests were conducted under moderate and aggressive conditions. In the machining tests, the 6-h cryo-treated electrode exhibited a 16.8% increase in material removal rate (MRR) under moderate conditions and a 19.7% increase under aggressive conditions compared to the reference electrode. The 12-h cryo-treated electrode showed similar MRR values to the reference electrode but improved tool wear resistance by 9.4% under moderate conditions. The kerf angle was minimized, indicating better hole verticality, in the 6-h cryo-treated electrode group. The improvement in machining performance was attributed to the enhancement in electrical conductivity of the electrodes, which increased by 28% for the 6-h cryo-treated electrode and 20% for the 12-h cryo-treated electrode. X-ray diffraction (XRD) analysis revealed shifts in peak positions and possible phase transformations due to cryogenic treatment. Surface roughness measurements showed improved surface conditions in the cryo-treated electrodes under aggressive conditions. The results indicate that cryogenic treatment enhances MRR, reduces tool wear, and improves surface quality in die-sink EDM. These improvements are attributed to increased electrical conductivity and changes in the internal structure of the brass electrode. [ABSTRACT FROM AUTHOR]

This paper refers to the topic of determining the kerf value and axis accuracy of a CNC plasma cutter for the cutting of 2, 4 and 6 mm thick plates of construction steel, aluminum and stainless steel. After the thorough description of the researched materials, a detailed experiment plan was created in the Design-Expert software package. After cutting the test samples the data were measured. Upon completion of the cutting, all test samples were measured, and the data regarding their dimensional deviations on x and y-axis and bore diameter deviations was tabularly shown and analysed with the Design – Expert software. Statistical analysis of the measured data was made so that the optimal kerf values and the equations which describe dimensional deviations for each material and thickness could be made, based on the dimensional deviation of the test samples. Along with the kerf values, analysis has also given insight in the accuracy of the x and y-axis of the machine. Finally, an algorithm for optimizing multiple criteria was utilized to determine the ideal kerf value for each material and thickness. The objective was to identify the precise kerf value that results in the highest possible accuracy for the dimensions of the workpiece in both the x and y directions, as well as for the bore diameter. [ABSTRACT FROM AUTHOR]

The high ductility behaviour and high hardening of Nickel–Titanium (NiTi) alloys during cutting make them one of the alloys with low machinability. In addition, poor chip breakage and high tool wear are observed when machining these materials with conventional manufacturing methods. One of the unconventional processing methods, abrasive water jet (AWJ), is an alternative method for cutting low machinability materials. In this study, NiTi shape memory alloy (SMA) was subjected to AWJ drilling under different machining parameters. The aim of the research is to determine the optimum kerf (K), surface roughness (Ra) and material removal rate (MRR) variables resulting from the drilling process by examining the effect of process variables such as water pressure (WP), stand-off distance (SoD) and feed rate used in AWJ machining of NiTi SMAs. Taguchi-based Gray Relational Analysis (GRA), one of the multi-criteria decision-making methods, was used to optimise machining parameters in the drilling of NiTi SMAs with AWJ. The effect percentages of the test levels in the drilling operations were determined using Analysis of Variance (ANOVA). As a result of the experimental study, optimum levels were obtained for K, MRR and Ra at low WP, medium SoD and high feed rate. According to the result obtained from ANOVA, the parameter with the highest effect on K, MRR and Ra was determined as feed rate with 34.65%. [ABSTRACT FROM AUTHOR]

This paper refers to the topic of determining the kerf value and axis accuracy of a CNC plasma cutter for the cutting of 2, 4 and 6 mm thick plates of construction steel, aluminum and stainless steel. After the thorough description of the researched materials, a detailed experiment plan was created in the Design-Expert software package. After cutting the test samples the data were measured. Upon completion of the cutting, all test samples were measured, and the data regarding their dimensional deviations on x and y-axis and bore diameter deviations was tabularly shown and analysed with the Design – Expert software. Statistical analysis of the measured data was made so that the optimal kerf values and the equations which describe dimensional deviations for each material and thickness could be made, based on the dimensional deviation of the test samples. Along with the kerf values, analysis has also given insight in the accuracy of the x and y-axis of the machine. Finally, an algorithm for optimizing multiple criteria was utilized to determine the ideal kerf value for each material and thickness. The objective was to identify the precise kerf value that results in the highest possible accuracy for the dimensions of the workpiece in both the x and y directions, as well as for the bore diameter.

Abstract The significance of liquids in abrasive wire sawing has been demonstrated in several studies. However, the performance of its spreading behavior is limited by the current development trend, where the wafer has a larger area and the kerf is narrower. Moreover, there are very few studies on the liquid spreading behavior in wire-sawn kerfs. Therefore, a 3D CFD (computational fluid dynamics) model is presented in this paper and used to simulate the liquid spreading behavior in a kerf based on a VOF (volume of fluid) method with a CSF (continuum surface force) model, which is used to simulate multiphase flow, and an empirical correlation for characterizing the liquid dynamic contact angle using UDF (user defined functions). Subsequently, parametric simulations are performed on the kerf area, kerf width, liquid viscosity, liquid surface tension, and liquid velocity at the inlet area of the kerf, and verification experiments are conducted to determine the validity of the simulation model. From the simulation and experimental results, three typical liquid spreading regimes that exhibit different effects on wire sawing in the kerfs are found, and their limiting conditions are identified using non-dimensional analysis. Subsequently, a prediction model is proposed for the liquid spreading regime based on a set of Weber and Capillary numbers. For wire sawing, an increase in the wafer area does not change the liquid spreading regime in the kerf; however, a reduction in the kerf width significantly hinders the liquid spreading behavior. Thereby, the spreading regime can be effectively converted to facilitate wire sawing by adjusting the physical properties and supply conditions of the liquid.

Dicing and filling is the most commonly used method to fabricate the piezoelectric composite by replacing part of the piezoelectric ceramics with the polymer. The dicing quality affects the composite performance, and the dicing mechanism is not clear now. In this study, a theoretical dicing mechanism for PZT-4H ceramics is introduced and validated by the experiments. The results show that, along the dicing depth direction, the dicing surface goes through brittle removal, hybrid of ductile and brittle removal, and pure ductile removal modes. The high wheel speed and low feed rate can help to get the low surface roughness and edge chipping size (width and height) due to the material removal mode transition. The diced kerfs are in saddle shape due to the dicing force variation and wheel vibration in different locations. The composite with high dicing surface quality and consistent size of dicing kerf has low mechanical quality factors variation. The impedance and phase angle at the resonance and anti-resonance frequencies are sharp, which indicates the perfect superposition of the energy from a different pillar. The inconsistent dicing kerf ruined the impedance and phase angle curve after superposition, which shows poor performance. [ABSTRACT FROM AUTHOR]

Due to the variety of benefits over traditional cutting techniques, the usage of laser cutting technology has risen substantially in recent years. The attributes of laser technology for leather cutting include adaptability, mass production, capability of cutting complicated patterns, ease of producing tailored components, and reduction in leather waste. In the present study, vegetable chrome-tanned buffalo leather specimens were cut using a 20 W laser diode with conventional and pulse width control in a photodiode-assisted laser cutting process. Emission rate, kerf width, carbonization, and material removal rate were considered as quality indicators. The higher power density associated with the pulse width approach reduces the interaction with the specimen, which results in a better emission rate and material removal rate, along with a lesser kerf width and carbonization. Using the MOORA approach, the optimal parameters of the present study were found to be a stand-off distance of 22 mm, a feed rate of 200 mm/min, a duty cycle of 75%, and a frequency of 20 kHz. The duty cycle can effectively control the pulse width at which the energy has been dissipated across the cutting zone. [ABSTRACT FROM AUTHOR]

Wire electric discharge machining (WEDM) is a famous machining process for manufacturing intricate and 3D complex geometries on tough difficult-to-machine superalloys and composites. Stainless steel 304 (SS 304) alloy has excellent corrosion resistance and forming faces which is used in aerospace, chemical, petrochemical industries, etc. The present work focuses on WEDM of SS 304 using a brass wire electrode of ϕ 0.25 mm with rough cut trailed by trim cuts to improve the machinability. WEDM experiments were conducted as per Taguchi's L9 experimental design with four-factor and three-level. The effect of pulse on time (Ton), pulse off time (Toff), current and wire offset during trim cuts on machinability characteristics, namely surface roughness, material removal rate (MRR), kerf width and microhardness, was analysed. Experimental results showed that trim cuts with varying wire offsets produced better surface finish, high MRR with hardness, and low kerf width compared with rough cut. Furthermore, surface characteristics of rough cut with trim cut surfaces were analysed using scanning electron microscope (SEM) images. Finally, grey relational analysis (GRA) was used to find the optimal input parameter combination and simultaneously optimize the selected machinability responses. [ABSTRACT FROM AUTHOR]

In this present study, the effect of processing parameters on cutting width (kerf), material removal rate (MRR), Ra (arithmetic mean deviation), Rq (root mean square deviation) and Rz (maximum height) values ​​as a result of wire electrical discharge machining (WEDM) of Ti-6Al-4V alloy was investigated. It is aimed to determine the optimum values of the cutting parameters to obtain the highest MRR value with the lowest kerf, Ra, Rq, Rz. Cutting experiments were carried out using three different voltages (46, 56, 66 V), three different dielectric fluid pressures (10, 12, 14 kg/cm2) and three different wire feed rates (8, 10, 12 m/min). The parameters used in the experiments were designed according to the Taguchi L9 (33) orthogonal array in order to reduce the experimental cost. Gray Relational Analysis (GRA), one of the multi-criteria decision-making methods, has been applied to optimize the machining parameters in the cutting process with the wire erosion machine. Analysis of variance (ANOVA) was used to determine the effect percentages of the processing parameters. By using the data obtained from the experiments, the prediction study of the experimental data was carried out with the Artificial Neural Networks (ANN) model. High correlation coefficients were obtained in the regression model created using the ANN technique, and it was observed that both models were suitable and usable to predict the answers. As a result of GRA, the most ideal sequence was determined as VG1LQ1WS1. Ideal conditions were determined as 46 V voltage, 10 kg/cm2 dielectric fluid pressure and 8 m/min wire feed rate. Using the optimum machining parameters, an improvement of 4.22%, 54.65%, 28.77%, 31.94% and 35.24% was obtained for kerf, MRR, Ra, Rq, and Rz, respectively. As for the results obtained from ANOVA the contribution rate of the voltage was 72.18%. However, the effect of wire feed rate and dielectric fluid pressure was not statistically significant. [ABSTRACT FROM AUTHOR]

Laminated metal-composite structures or fiber metal laminates (FMLs) are advanced engineering materials currently being utilized in several distinct applications, especially in aircraft and automobile manufacturing industries where an improved impact and fatigue resistance are required. Machining of FMLs is an important task in obtaining near-net shapes for joining and assembly of the components. However, the delamination occurs during conventional machining making FMLs as difficult-to-machine materials. Therefore, the present study will look into the abrasive water jet cutting (AWJC) of novel fiber intermetallic laminates (FILs) made of with alternatively stacked carbon/aramid fiber adhesively bonded with r-GO filled epoxy resin matrix and Nitinol shape memory alloy sheet embedded laminates. The AWJC experiments were performed on fabricated FILs to investigate the cut quality features including kerf taper (Kt), surface roughness (Ra) and kerf deviation (KD) by varying addition of r-GO from 0-2 wt% in the laminates, traverse speed (400-600 mm/min), waterjet pressure (200-300MPa) and nozzle height (2-4 mm), respectively. Statistical results obtained through ANOVA reveals that the traverse speed and nozzle height are the utmost significant variables which influencing the cut quality characteristics followed by waterjet pressure. Surface morphology analysis shows the wear and erosion mechanism of FILs at varying AWJC conditions. For an improved cut quality, the optimal AWJC parameters are achieved through a metaheuristic-based Barnacles Mating Optimization Algorithm (BMOA). [ABSTRACT FROM AUTHOR]

The aim of this work is to adopt artificial immune system approach to optimize Abrasive water jet machining parameters during machining on Monel. The process parameters considered are pressure of pump, flow rate of abrasive materials, traverse/cutting speed and standoff distance. In AWJ process parameters plays a crucial role in finding the economics and ability of machining process. The objective behind this experimental study is to conduct a research and analysis of process parameters influence on Kerf and Ra of the Monel 400 work-piece. Taguchi's L16 Orthogonal array approach is used in order to design the experiments to measure the surface roughness and kerf. The order of significance of each input parameters on surface roughness and kerf is determined using Analysis of variance (ANOVA). Multi linear regression model (MLRM) was developed for both kerf and surface roughness. Further, the combined MLRM equation of kerf and surface roughness was optimized using artificial immune system (AIS) algorithm and it was found that at traverse speed of 115.3965 mm/min, stand-off distance of 1.400149 mm, abrasive flow rate of 782.7314 gm/min and pressure of 3686.783 bar were the best set of values to achieve the minimum possible kerf and Ra together. [ABSTRACT FROM AUTHOR]

Laser machining is a cutting-edge thermal energy-based industrial methodology that can be employed to replace the traditional mechanical machining practices in micro-domain applications. In this work, complex hexagonal shape profiles were cut on the surfaces of Nickel-based superalloy (Alloy 276) by fiber optics laser cutting system. Response surface methodology – Central Composite Design approaches were attempted for optimizing laser machining factors to obtain the better output responses. ANOVA was used to identify the significant machining factors which affect the cut quality characteristics. The desirability approach in multi-response optimization was deployed to achieve the minimal kerf width, low surface roughness, minimum heat affected zone while simultaneously increasing the material removal rate. To validate the predicted results obtained from the desirability index analysis, confirmation test was conducted based on a higher desirability index value. The result reveals that the error percentage is less than 5 for all the responses. The results of the confirmation test show that the proposed procedures are effective in improving laser machining parameters for obtaining the better responses. [ABSTRACT FROM AUTHOR]

In plasma arc cutting (PAC), the characteristics of the gas flow exiting the nozzle significantly influence the cut quality. The high-pressure jet in PAC forms complex shockwave structures when it is incident on the metal to be cut. In this study, the flow behavior inside the kerfs of various geometries derived from an actual PAC workpiece is assessed. The shape of the cutting front in the kerf varies with the changing cutting speed. A high cutting speed yields a curved cutting front, resulting in unwanted gas flow behavior and adversely influencing the cutting performance. In this study, a computational fluid dynamics simulation model was used to analyze the effects of a curved cutting front on the gas flow behavior during the PAC process. The gas flow patterns obtained from the numerical simulations were qualitatively compared with the Schlieren experiment results. The analysis results indicated that the curvature of the cutting fronts generated oblique shockwave structures that significantly reduced the flow velocity. In particular, the weak shock structures throughout the curved cutting front gradually decreased the flow velocity. The critical flow velocity was realized in the kerf with a highly curved cutting front, beyond which the vertical penetration of the material was not possible. The shear stress lines concurred with the striation patterns on the kerf walls, thereby validating the numerical analysis results. [ABSTRACT FROM AUTHOR]

The need for soft polymer (such as acrylonitrile butadiene rubber (ABR)) components in mating applications is increasing in several sectors, viz. automobile, mining, and marine, due to their viscoelastic nature with improved surface quality and tighter geometric tolerances. Therefore, this paper aims to compare the effect of cryogenic conditions on the performance parameters of the suspension-type abrasive water jet (S-AWJ) machining and investigate the kerf characteristics of the top and bottom surface by comparing the waviness of the cut profiles and abrasive contamination of the top surface near the vicinity of the slot under conventional (room temperature) and cryogenic (liquid nitrogen (LN2)) conditions. The study found that the use of LN2 positively affected the performance parameters (Kerf taper ratio (KTR) and material removal rate (MRR)) due to a sudden increase in Young's modulus and a decrease in elasticity of the machining zone. The cryogenic-assisted S-AWJ at the highest water jet pressure (WJP) (250 bar) produced better kerf characteristics through uniform and waviness-free top and bottom kerf profiles than the other experimental sequences. The use of LN2 resulted in the embrittlement of ABR, due to which less garnet abrasive particle contamination was observed during cryogenic-assisted S-AWJ machining. [ABSTRACT FROM AUTHOR]

The kerf taper angle is one of the most significant parameters for AWJ cutting. Choosing the best cutting parameters is critical to reducing the kerf taper. Therefore, the aim of this work is to demonstrate on to implement RSM in conjunction with the Rat swarm optimizer algorithm to optimize the kerf taper angle of a Titanium alloy. Thirty-two number of experiments were conducted according to CCD considering five process parameters namely jet traverse rate, water jet pressure, abrasive flow rate, stand-off distance and diameter of focusing nozzle to achieve kerf taper angle. A second-order full quadratic model is used for mathematical modeling. The result demonstrates that the model is sufficiently adequate and acceptable. A recent Rat Swarm Optimization (RSO) algorithm is considered for finding out the global optimal solution. It is observed that after optimizing the process that the jet traverse rate of 1.952 mm/sec, water jet pressure of 250.548 MPa, abrasive flow rate of 0.554 kg/min, stand-off distance of 3.75 mm and diameter of focusing nozzle of 2.0 mm gives minimized with 0.754 degree of kerf taper angle. A series of verification tests are carried out to ensure that the optimization technique is accurate in determining the best levels of process. [ABSTRACT FROM AUTHOR]

The purification of laser keyhole is an important means to remove the oxide layer of laser-MIG hybrid welding of aluminum alloy. Four common auxiliary gases (argon, nitrogen, air and oxygen) were used to prepare kerf with different characteristics, which were defined as argon-weld, nitrogen-weld, air-weld and oxygen-weld. The results show that the remelted layer has little effect on the weld morphology. Microstructures characteristics of Argon-welds and nitrogen-welds were the same as machined welds, while the narrow columnar grain zone and coarsen grains exist in air-welds and oxygen-welds. When the thickness of kerf remelted layer increases, the width of columnar grain zone is reducing and the diameter of equiaxed grain is increasing. The argon-weld is with the best tensile property. When the thickness of remelted layer (d) is less than 70 μm, the tensile strength and elongation of argon-weld can reach 278 MPa and 3.1% respectively, which equivalent to that of machined weld. The tensile property of nitrogen-weld is slightly lower than that of argon-weld because of aluminum nitride impurities. The tensile properties of air-weld and oxygen-weld are low because of a large number of oxide impurities and grain coarsening. Regardless of the types of kerf, when the d is less than 136 μm, the tensile strength reaches more than 250 MPa, which meets the application requirements.

abrasive water jet is one of the most popular cutting methods today due to its ability and unique features such as the ability to cut complex shapes as well as the wide range of materials and non - creation of thermal distortion at the cutting site. The accuracy of the process is mainly due to selecting the cutting parameters. The sheet used in this study is aluminum 7075 with a thickness of 25 mm. In this research, for water jet pressure, forward speed and nozzle distance to the surface of the workpiece, three surfaces and for the impingement angle of two surfaces were considered. In order to investigate the quality of the cut - off area, the effect of process parameters on the high and low width of the cut section and also the cut - surface slope is investigated. Finally, the cut gap created by this process has special geometrical features that in some cases is the limitation of the process. The results showed that the change in the direction of the water jet from the perpendicular to the surface of the work piece, although the width of the cutting crack cannot be changed, the surface quality decreases and the cutting surface slope increases. [ABSTRACT FROM AUTHOR]

Bismaleimide-based hybrid fiber composites (BMI) with their expanded thermomechanical properties have been broadly utilized in Aircraft primary applications. The supplanting of carbon fiber with other fiber (kevlar/glass/basalt) is redone to the requirements of the business. To maintain the surface quality, the hybrid composites can be machined with unconventional methods like Abrasive Water jet Machining. In this work, the exploratory examination of interaction boundaries, such as Water pressure (Wp), Transverse speed (Ts), Standoff distance (SOD), Abrasive mass flow rate (ma) of AWJM on hybrid BMI composites was done. Experiments were conducted based on Design of Experiments created from Response surface strategy utilizing Central Composite Design (CCD) and the impact of interaction boundaries on kerf taper and surface roughness were analyzed. The experimental outcomes showed that for the minimum kerf angle, the significant parameters were transverse speed, water pressure, and abrasive flow rate and for minimum surface roughness, transverse speed was the significant parameter. The microstructure analysis revealed that plowing deformation of fiber and abrasive particle embedment at high speed and mass flow rate led to delamination of fiber, which was limited by optimal parameters essentially diminishing kerf taper and surface roughness. [ABSTRACT FROM AUTHOR]

Inconel-625 is a tough-to-cutting material used in ultra-supercritical power plants for flanges, offshore oil sectors, and turbine blades, among other high-temperature components. The objective of this article is to determine the link between four key process independent variables: traverse speed (TSP), abrasive mass flow rate (AMFR), abrasive aqua jet pressure (AAJP), and gap distance (Gd) to the surface roughness (SRa), kerf angle (KEA), and erosion rate (MRR). The response surface methodology-Central composite design (RSM-CCD) was used to perform the experimental interpretations. The influence of individual abrasive aqua jet cutting (AAJC) factors was determined using analysis of variance technique (ANOVA). It was found that AAJP is the dominant factor in the responses. When the AAJP reached its maximum value of 300 MPa, the SRa and KEA reduced by 27.19% and 13.83%, respectively, the MRR improved by 23.71%. The Desirability analysis is handled to optimize the AAJC parameters of Inconel-625. The optimal values of parameters obtained were 300 MPa AAJP, 75 mm/min TSP, 2.4 mm Gd, and 0.55 kg/min AMFR to minimize SRa, KEA, & maximize the MRR. The scanning electron microscope is used to examine the surface morphology and erosion mechanisms. [ABSTRACT FROM AUTHOR]

This study investigates the influence of the stand-off distance (SoD), laser speed (LS) and laser power (LP) on kerf geometry (upper width Wu, down width Wd and kerf angle KA) and mean surface roughness (Ra) during CO2 laser cutting of 3D-Printed Polyethylene-Terephthalate-Glycol (PET-G) thin plates. A full factorial design is implemented, having two levels for SoD and three levels for LS and four levels for LP, resulting in twenty-four (24) cuts. The specimens were manufactured with the Fused Filament Fabrication (FFF) process and had a thickness of 4 mm. First, the Wu, Wd, and KA parameters were measured. Then, the specimens were cut into 24 smaller parts, and the Ra of the processed surfaces was measured. After analyzing the results using descriptive statistical analysis and contour plots corresponding to the two objectives of KA and Ra, a feed-forward and backpropagation neural network (FFBP-NN) was applied. After a series of subsequent training, it was found that the 3-10-2 NN architecture was quite efficient in explaining the variation in terms of the responses, thus having merit in practical applications related to laser cutting. The LC surfaces showed much better Ra (7.2-12 μm) than those in the literature for FFF parts surfaces without post-processing (10.3-30 μm). [ABSTRACT FROM AUTHOR]

In this study, electrode wear caused by machining from cold work tool steel with heat treated 60-62 HRC hardness was investigated by using electro erosion method and Cupro MAX CuCrZr electrode. The workpiece and electrode material are eroded by melting and evaporation as a result of the electrical arc (sparking) that occurs between the electrode and the workpiece in the dielectric environment. These erosions can be interpreted by changes in electrode form measurements and surface roughness. In this context, erosion process was performed using three different current values (6.25, 12.5, 25 A), three different pulse on times (3, 6, 9 µs) and pulse off times (4, 6, 8 µs), respectively, and the electrode wear rate of these processing parameters, the effects on kerf angle and surface roughness were analyzed by macro and analytical measurements. As a result of the analysis, with increasing current, machining time decreased due to increased sparking between workpiece and electrode, but the average surface roughness, kerf angle and wear rate of the electrode increased. It has been determined that as the pulse on time increases, the electrode wear rate decreases. The reduction in electrode wear resulted from the increase in the strength of the electrode due to the protective layer formed by the adhesion of the dielectric fluid and carbon particles released from the workpiece to the electrode surface.

The novelty of EDM machining as a drilling operation for composite materials means that there is no consensus on the influence of the parameters that optimise the final quality. For these reasons, a characterisation of the EDM drilling process of a unidirectional composite material has been developed. The influence of several cutting parameters has been related to the quality of the final hole obtained. Thus, macrogeometric aspects in terms of conicity and final diameter and microgeometric aspects in terms of surface quality have been evaluated. In addition, the final state of the material and the wear of the electrode have been evaluated by visual inspection, allowing the range of cutting parameters that offer the best performance to be established. Finally, a series of contour diagrams based on predictive models have been obtained to establish a direct relationship between input and output variables. [ABSTRACT FROM AUTHOR]

Laser cutting of copper-based alloy sheets is very difficult due to their high reflectivity, which can be modified with graphitization. The optimal parameters for a 2.5 mm thick brass sheet were determined by examining the laser beam parameter variations and the laser cut kerfs. The best characteristics of kerfs were obtained when the surface was graphitized, the laser frequency was 200 Hz, the applied laser speed was 1400mm/min on 2500 W power and the focal point was under the surface by 0.8 mm. The applied working gas was nitrogen. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to obtain strong materials with multiwall carbon nanotubes (MWCNTs) doped and investigate laser cut of MWCNTs also find the effect of the laser cutting parameters on composite materials. Design/methodology/approach: The laminated composite plates were manufactured by using a vacuum infusion process. The mechanical properties of the composite materials produced were determined according to American Society for Testing and Materials (ASTM) D3039M, ASTM D3171, ASTM D 792 and ASTM D2583. A 130 Watts carbondioxide (CO2) laser cutting machine was used for drilling the two different composite plates with a thickness of 1.6–1.5 mm. Three variables were considered as process parameters including laser power (in three levels of 84.50, 104.00 and 127.40 W), cutting speed (in three levels of 4, 6, 8 mm/s) and 14 mm fixed focal position. Findings: The fibers could not be cut due to insufficient melting in the experiments performed using 84.50 and 104.00 W laser power but the cutting was successfully completed when the laser power was 127.40 W. However, as the cutting speed increased, the contact time of the laser beam with the material decreased, so the kerf decreased, but the increased laser power created a thermal effect, causing an increase in hardness around the cutting surface. This increase was lower in MWCNTs doped composites compared to pure composites. It has been found that the addition of nanoparticles to layered glass fiber composite materials played an effective role in the strength of the material and affected the CO2 laser cutting quality. Originality/value: This study is a unique study in which the CO2 laser cutting method of MWCNT-doped composite materials was investigated and the machinability without cutting errors, such as delamination, splitting, distortion and burring using the most suitable laser cutting parameters was revealed. [ABSTRACT FROM AUTHOR]

WEDM (Wire electrical discharge machining) is a precision machining method for cutting electrically conductive materials. It is an unconventional machining process that produces precision parts that match the dimensional tolerances of our designs within the range of ±0.0001mm. As the residual stress results in premature failure of parts, the WEDM is preferred for hard to machine materials such as Inconel, Nickel, and other Super alloys. In the present paper, earlier and recent work was reviewed, segregated and evaluated on the effect of wire material, diameter, dielectric fluid, wire wear, pulse on and off times and machining characteristics such as kerf size, machining efficiency, material surface characteristics, etc. This paper also focused on hybrid and ultrasonic-assisted WEDM used for machining of different materials. This paper discussed the major research studies in WEDM.

With steadily rising expanse of the engineering sector, demand for composite materials has been growing progressively over the years. Particularly, glass fiber reinforced polymer (GFRP) composites are being increasingly applied in various industries in the aerospace, automobile, and construction sectors due to their lightweight and superior performances. The present investigation examines the effect of traverse rate, jet pressure, standoff distance, and multi-walled carbon nanotubes (MWCNT), mixed with epoxy/glass fabric nanocomposites, on abrasive water jet machining (AWJM) responses, such as kerf taper (KT), surface roughness (Ra), material removal rate (MRR), entrance and exit delamination factor (DF) by using the Taguchi approach. The study has established that the addition of MWCNT in the GFRP laminates optimizes the machining responses. The investigation, using analysis of variance approach, revealed the most dominant parameter, which influences the machining performance of the composites. A significant enhancement in AWJM responses could be attained with optimal parameters. And also validates using surface examinations. [ABSTRACT FROM AUTHOR]

In this study, the holes of glass fiber reinforced polymer (GFRP) and multi-walled carbon nanotubes (MWCNTs) doped GFRP composite materials were drilled using abrasive water jet (AWJ), CO2 laser cutting, orbital drilling, and punching methods; the effects of these methods on hole quality were determined. The hole entry and exit dimensions were obtained equal and in the desired size by orbital drilling; thus, kerf formation was prevented due to the lateral and face milling of the end mill. The surface hardness change was not observed in the hole circles obtained with the orbital drilling and punching methods. However, epoxy hardening was observed in the hole circles obtained by laser cutting due to the heat effect of laser beam. In AWJ method, matrix-fiber integrity was disrupted, and delamination was observed due to the effect of water pressure and kinetic energy; consequently an increase in material thickness was observed and surface hardness decreased. It was determined that MWCNTs additive increased the surface hardness of composites and maintained its hardness and durability in post-cutting measurements. Splintering and burring were not seen in any method, but fiber carbonization was observed in the inner parts of the hole due to thermal effects in laser cutting. [ABSTRACT FROM AUTHOR]

A hybrid approach through combining genetic algorithm (GA) and adaptive neuro-fuzzy inference system (ANFIS) for modeling the correlation of laser beam cutting (LBC) parameters and enhancing the quality performance characteristics of machined Hastelloy C276 is emphasized. The LBC experiments are performed by considering gas pressure (GP), cutting speed (CS), pulse energy (PE) and stand-off distance (SOD) as input parameters. The output responses are material removal rate (MRR), kerf taper (KT) and surface roughness (Ra) for the present investigation. The optimal ANFIS training variables are obtained through GA. The training, testing errors, and statistical validation parameter results exposed that the ANFIS learned by GA is outperformed in forecasting LBC responses. In addition, to obtain the optimal combinations of LBC parameters, the multi-response optimization based on maximizing MRR and minimizing KT and Ra was performed using a trained ANFIS network coupled with a whale optimization algorithm (WOA). The responses such as MRR of 236.98 mg/min, KT of 1.135° and Ra of 1.109 µm are forecasted for the optimum cutting conditions: GP of 3 bar, CS of 319.8 mm/min, PE of 5.93 J and SOD of 2.97 mm, respectively. Furthermore, the WOA predicted results are validated by conducting confirmatory experiments. [ABSTRACT FROM AUTHOR]

In this work, two typical surface characteristics, i.e., mean surface roughness and angle of the kerf during laser processing of 3D-printed Polylactic Acid (PLA) plates with 4.00 mm in thickness, are investigated. A carbon dioxide laser was utilized to separate 27 work pieces of rectangular shape. The governing laser parameters, speed of cutting and laser power, were varied according to full factorial experimental methodology. An orthogonal array (OA) having nine combinations was implemented, and nine specimens were cut with the same set-up and the same parameters three times (27 replicates in total). The experimental results were analyzed using descriptive statistical analysis, i.e., histograms, box plots, interaction charts and optimized using analysis of means (ANOM) plots as well as ANOVA analysis. The data analysis indicated that laser speed is the dominant parameter for the kerf angle, whilst both the laser velocity and power are important for mean surface roughness of the cut surface for PLA 3D-printed parts. The spread of the data is smaller in Y direction, which indicates that the weaving phenomenon affects the laser cut performance. [ABSTRACT FROM AUTHOR]

Abrasive water jet (AWJ), which is a non-traditional machining method, is more widely used today. Various materials such as metals, ceramics, polymers, and composites can be easily machined with AWJ. In this study, cutting of St37 steel plates in stacked form with AWJ was investigated. The experiments were carried out according to the general full factorial design. Experimental parameters were inter-stack distance, traverse speed, and abrasive mass flow rate also each of these parameters was chosen at three levels. Surface roughness and kerf widths were examined to determine the cutting performance. Analysis of variance (ANOVA) of all outputs was provided and thus the effects of experimental parameters and their levels on cutting performance were found. The most effective parameters for surface roughness and kerf width in almost all conditions were abrasive mass flow rate and inter-stack distance, respectively. In addition, a concept for multi-simultaneous cutting was developed with mathematical differences of surface roughness and kerf taper angle. Thus, optimum levels of experimental parameters were found for minimum mathematical differences. [ABSTRACT FROM AUTHOR]