Recast Layer Thickness Research Articles

Surface modification of biodegradable Mg alloy by adapting µEDM capabilities with cryogenically-treated tool electrodes.

Biomaterials are engineered to develop an interaction with living cells for therapeutic and diagnostic purposes. The last decade reported a tremendously rising shift in the requirement for miniaturized biomedical implants exhibiting high precision and comprising various biomaterials such as non-biodegradable titanium (Ti) alloys and biodegradable magnesium (Mg) alloys. The excellent mechanical properties and lightweight characteristics of Mg AZ91D alloy make it an emerging material for biomedical applications. In this regard, micro-electric discharge machining (µEDM) is an excellent method that can be used to make micro-components with high dimensional accuracy. In the present research, attempts were made to improve the µEDM capabilities by using cryogenically-treated copper (CTCTE) and brass tool electrodes (CTBTE) amid machining of biodegradable Mg AZ91D alloy, followed by their comparison with a pair of untreated copper (UCTE) and brass tool electrodes (UBTE) in terms of minimum machining-time and dimensional-irregularity. To investigate the possible modification on the surfaces achieved with minimum machining-time and dimensional-irregularity, the morphology, chemistry, micro-hardness, corrosion resistance, topography, and wettability of these surfaces were further examined. The surface produced by CTCTE exhibited the minimum surface micro-cracks and craters, acceptable recast layer thickness (2.6µm), 17.45% improved micro-hardness, satisfactory corrosion resistance, adequate surface roughness (Ra: 1.08µm), and suitable hydrophobic behavior (contact angle: 119°), confirming improved biodegradation rate. Additionally, a comparative analysis among the tool electrodes revealed that cryogenically-treated tool electrodes outperformed the untreated ones. CTCTE-induced modification on the Mg AZ91D alloy surface suggests its suitability in biodegradable medical implant applications.

Optimization and Microstructural Studies on the Machining of Inconel 600 in WEDM Using Untreated and Cryogenically Treated Zinc Electrodes.

Any industry that manufactures dies, punches, molds, and machine components from difficult-to-cut materials, such as Inconel, titanium, and other super alloys, largely relies on wire electrical discharge machining (WEDM). In the current study, the effect of the WEDM process parameters on Inconel 600 alloy with untreated zinc and cryogenically treated zinc electrodes was investigated. The controllable parameters included the current (IP), pulse-on time (Ton), and pulse-off time (Toff), whereas the wire diameter, workpiece diameter, dielectric fluid flow rate, wire feed rate, and cable tension were held constant throughout the experiments. The significance of these parameters on the material removal rate (MRR) and surface roughness (Ra) was established using the analysis of the variance. The experimental data acquired using the Taguchi analysis were used to analyze the level of influence of each process parameter on a particular performance characteristic. Their interactions with the pulse-off time were identified as the most influential process parameter on the MRR and Ra in both cases. Furthermore, a microstructural analysis was also performed via scanning electron microscopy (SEM) to examine the recast layer thickness, micropores, cracks, depth of metal, pitching of metal, and electrode droplets over the workpiece surface. In addition, energy-dispersive X-ray spectroscopy (EDS) was also carried out for the quantitative and semi-quantitative analyses of the work surface and electrodes after machining.

Performance analysis of WEDM during the machining of Inconel 690 miniature gear using RSM and ANN modeling approaches

Abstract The present work aims to carry out a feasible study of wire electro-discharge machining (WEDM) during the machining of Inconel 690 superalloy gears. Processing conditions of power-on time, power-off time, current, and spark-gap voltage are varied to evaluate the process performance in terms of material removal rate (MRR), surface roughness (SR), and wire consumption. Parametric optimization has been carried out using combined approach of response surface methodology (RSM) and artificial neural network (ANN). Results revealed that ANN predicted values are 99% in agreement with the experimental results which validates its effectiveness as compared to RSM predicted values. A viability study of noise characteristics of the processed gear is also done using a noise testing setup. Additionally, FE-SEM has been used to analyze the machined surface’s topography. Greater discharge energy brought by a longer pulse length raises the values of MRR, SR, and recast layer thickness (RLT). This study explores the capability of WEDM to produce a more precise and smooth gear profile as compared to other conventional machining methods. Additionally, RLT and microhardness of the machined surface have been critically studied to comprehend the better understanding of the process mechanism.

Surface integrity of NiTi-SMA during WEDM: effect of spark parameters

ABSTRACT The current study looks at surface integrity measures for example surface crack density, surface roughness, recast layer thickness, and foreign elements content in wire electric discharge machining (WEDM) of the Ni55.95Ti44.05 shape memory alloy (SMA) with purposefully varied spark parameters (spark frequency, spark energy density, and spark gap voltage). Surface roughness has a similar tend to surface crack density, which increases with an increase in spark energy density and decreases with an increase in spark gap voltage and spark frequency. As the spark energy density declines and the spark gap voltage and spark frequency rise, foreign elements content and recast layer thickness decrease. Scanning electron microscope (SEM) and optical profilometer observations of the surface topography of SMA following WEDM show the presence of lumps, voids, pockmarks, discharge craters, microcracks, and a layer of melted material that has resolidified. Energy dispersive spectroscopy (EDS) studies show that foreign elements are deposited on machined surfaces from wire electrode and dielectric fluid.

Finishing the surface micro-layer of additively manufactured TiAl alloy using electro-thermal discharge assisted post-processing

Selective laser melting (SLM) of titanium–aluminium (TiAl) alloy components has gained significant attention in the modern industrial world. The flexibility of the SLM process in producing complex shapes with minimum utilization of material and energy makes it dominant over other manufacturing techniques. As aerospace and biomedical industries demand complex-shaped TiAl alloy components, part fabrication using SLM becomes the ultimate solution. However, the unacceptable level of surface integrity and anisotropic behavior of SLM components demand post processing operations such as laser polishing, chemical polishing, and conventional polishing methods. In this study, a recently developed polishing method called wire electrical discharge polishing (WEDP) is performed on TiAl alloys for obtaining a smooth and defect-free surface. This study aims to investigate the micro-layer modification occurring to the WEDP-processed surface in detail. The experimental results establish the effectiveness of WEDP method in terms of improved surface integrity. The surface finish (Sa) got enhanced by ~88% after WEDP processing. In addition, the thickness of recast layer formed by WEDP was found to be minimum. Moreover, post-processing of TiAl alloy resulted in better surface morphology specifically at lower settings of peak current. It is noteworthy that the migration of wire material was minimum with zinc-coated brass electrode compared to the normal brass electrode. Hence, coated wire electrodes are recommended for WEDP process. In short, an excellent surface integrity can be achieved using WEDP process through favorable surface modification aided by lower peak current and coated wire electrodes. Furthermore, less electrode wear observed in WEDP process enables the deployment of lower feed rates leading to minimal electrode consumption.

Influence of Maghemite (γ-Fe2O3) Nano-Powder Mixed Micro-EDM on the Surface Integrity Characteristics of Co-Cr-Mo

Surface integrity in electric discharge machining (EDM) has always been a major concern in the manufacturing industry. Although EDM with powder suspended dielectric has shown good potential in enhancing material removal rate and improving surface finish, the influence of the same on overall surface integrity is not very clear. The current work utilized (γ-Fe2O3) nano-powder and evaluated its role in combination with concentration and machining parameters, on surface roughness (Ra, Rmax), surface crack and thickness of recast layer, during powder-mixed micro-EDM (PMµEDM) of Co-Cr-Mo. SPM data are obtained through the database and its morphologies and meteorology are studied using the gwyddion software. Results showed that significant reduction in surface roughness, crack density and recast layer thickness is possible with the PMµEDM process.

Compensation method of wire electrode wear for reciprocating micro wire electrical discharge machining

Reciprocating micro wire electrical discharge machining (Micro-WEDM) has the advantage of high thickness cutting because it mainly relies on the high wire speed to remove discharge production. The wire electrode wear (WEW) not only affects the machining stability and quality, but also greatly increases the risk of wire breakage in long cycle machining. Aiming at the WEW of the micro wire electrode used in reciprocating, a method of introducing compensation voltage between pulse interval (Toff) is proposed in this paper. This method can enhance the existing electrochemical effect in WEDM and compensate the WEW by means of metal ion reduction deposition effect. The verification experiment of no-load pulse indirectly shows the feasibility of the compensation method. Too large compensation voltage will affect the Toff deionization and machining stability. Its value should be less than the maintenance voltage of normal discharge. The average thickness of recast layer decreases first and then increases with the increase of compensation voltage. The minimum thickness of recast layer is about 4.7 μm at 15 V, which is 62.4 % lower than that without compensation voltage. The high conductivity dielectric can reduce the WEW, while the compensation voltage can greatly enhance this effect. Compared with the initial cutting stage，the micro wire electrode has no wear basically until the cutting area exceeded 50,000 mm2, and the cutting speed maintains above 45 mm2/min. The distribution of elements on the surface of wire electrode indicates that the strength of electrolysis is improved by the method of WEW compensation.

Experimental Characterization of Laser Trepanned Microholes in Superalloy GH4220 with Water-Based Assistance.

An experiment using water-assisted millisecond laser trepanning on superalloy GH4220 was carried out, and the effects of pulse energy on the hole entrance morphology, diameter, roundness, cross-section morphology, taper angle, sidewall roughness, and recast layer in air and with water-based assistance were compared and analyzed. The results show that, compared with the air condition, the water-based assistance improved the material removal rate and hole quality, increased the diameter of the hole entrance and exit, increased the hole roundness, decreased the hole taper angle, decreased the hole sidewall roughness, and reduced the recast layer thickness. In addition, under the combined action of water and steam inside the hole, the sidewall surface morphology quality was improved. Compared with the air condition, the spatter around the hole entrance was reduced, but the oxidation phenomenon formed by the thermal effect surrounding the hole entrance with water-based assistance was more obvious. The research provided technical support for the industrial application of millisecond laser drilling.

Implementation of Passing Vehicle Search Algorithm for Optimization of WEDM Process of Nickel-Based Superalloy Waspaloy.

Nickel-based superalloys find their main use in missile engines, atomic devices, investigational aircraft, aerospace engineering, industrial applications, and automotive gas turbines, spacecraft petrochemical tools, steam power, submarines, and broader heating applications. These superalloys impose certain difficulties during the process fabrication owing to their levels of higher hardness. In the current study, the precise machining of Waspaloy was attempted through the wire electrical discharge machining (WEDM) technique. A multi-objective optimization has been performed, and the influence of multi-walled carbon nanotubes (MWCNTs) has been assessed using the passing vehicle search (PVS) algorithm. The effects of machining variables like current, Toff, and Ton were studied using the output measures of material removal rate (MRR), recast layer thickness (RLT), and surface roughness (SR). The Box-Behnken design was applied to generate the experimental matrix. Empirical models were generated which show the interrelationship among the process variables and output measures. The analysis of variance (ANOVA) method was used to check the adequacy, and suitability of the models and to understand the significance of the parameters. The PVS technique was executed for the optimization of MRR, SR, and RLT. Pareto fronts were derived which gives a choice to the user to select any point on the front as per the requirement. To enhance the machining performance, MWCNTs mixed dielectric fluid was utilized, and the effect of these MWCNTs was also analyzed on the surface defects. The use of MWCNTs at 1 g/L enhanced the performance of MRR, SR, and RLT by 65.70%, 50.68%, and 40.96%, respectively. Also, the addition of MWCNTs has shown that the machined surface largely reduces the surface defects.

Experimental investigation of effective parameters on productivity improvement of the EDM process for corrosion-resistant metals

Inconel 625 superalloy and stainless steel 304 are known for their significant corrosion resistance along with their high hardness and strength. Therefore, they are used in a wide range of industries, including oil and gas and nuclear. Electrical discharge machining is among the most widely used processes for machining of these metals. However, this process has limitations, such as low material removal efficiency, high surface roughness, and the formation of a recast layer. Therefore, in this study, the effective parameters on increasing the material removal efficiency and reducing recast layer thickness are investigated. These parameters include the dielectric fluid, electrode material, discharge current, and pulse duration. After performing the test matrix, the effect of each of the input parameters on the material removal rate, surface roughness, and thickness of the recast layer is evaluated using the ANOVA method. The results of this analysis showed that the type of dielectric fluid and the presence of silver oxide nanoparticles have a significant effect on output variables. When using sunflower oil fluid containing nanoparticles and the silver electrode, the recast layer and surface roughness are reduced, while the average material removal rate increases by 40% compared to the traditional mode. Also, due to the biodegradability of deionized water and sunflower oil fluids, the environmental sustainability of the process in this study is increased and while increasing productivity, it leads to the sustainable development of the EDM process.

Effect of multi-walled carbon nanotubes on the performance evaluation of nickel-based super-alloy–Udimet 720 machined using WEDM process

The diverse capabilities of nickel-based super-alloy (Udimet 720), like robust mechanical strength, ductility, resistance to excessive temperature deformation, and advanced corrosion and oxidation resistance, make it suitable for use in multiple applications. These super-alloys are identified as extremely difficult materials for machining to meet feature and manufacturing requirements. In the present work, we demonstrated the machining of Udimet 720 by employing the wire-electrical discharge machining (WEDM) technique. Pulse-on-time (Ton), pulse-off-time (Toff), current, and MWCNT amount were preferred as input variables. The effect of selected design variables was studied on material removal rate (MRR), surface roughness (SR), and recast layer thickness (RLT). Box-Behnken design was utilized to design an experimental matrix. For statistical analysis, analysis of variance (ANOVA) was employed. From ANOVA, the current had the highest contributor with 35.85% to affect MRR, while MWCNT amount was found to be the highest contributor for deciding the values of both SR and RLT with contributions of 42.66% and 40.07%, respectively. The addition of MWCNT at 1 g/L has substantially improved MRR from 0.8546 to 1.2199 g/min, SR reduced from 5.88 µm to 2.98 µm, and reduction in RLT from 17.8 to 11.61 µm. The passing vehicle search (PVS) algorithm was implemented, and the results of single-objective optimization presented the largest MRR of 1.8883 g/min, least SR of 1.89 µm, and least RLT of 9.70 µm. Additionally, a set of non-dominated solutions was obtained through Pareto optimal fronts. A small acceptable deviation was detected among the actual and forecasted results from PVS algorithm. It clearly reveals the acceptance of the PVS technique in the present study for Udimet 720. Lastly, the significance of MWCNT amount on surface textures was revealed by employing scanning electron microscopy (SEM).

Study and optimisation of WEDM parameters of AISI P20+Ni using RSM and hybrid deep neural network

ABSTRACTThe main task in Wire Electrical Discharge Machining (WEDM) is to select the proper tool material for machining the workpiece to get better surface finishing and high cutting speed. To overcome these challenges, nowadays, coated electrodes are used. The main objective of this research work is to study the impact of certain input parameters such as pulse off-time, pulse on-time, servo voltage, and peak current in WEDM on Material Removal Rate (MRR), Recast Layer Thickness (RLT), and Surface Roughness (SR) output parameters by using zinc-coated brass wire as an electrode and AISI P20+Ni (DIN 1.2738) as the workpiece. One of the hardest materials used to make die for plastic moulds. The study is carried out experimentally and then compared with the design done by response surface methodology (RSM) using ANOVA and hybrid deep neural network (DNN) predicted values, which are optimised based on Manta ray foraging optimisation (MRFO) to obtain more precise outputs. The developed RSM and hybrid DNN+MRFO were designed in Design Expert 12 and MATLAB R2020a platforms and achieved 90% average prediction accuracy in the DNN+MRFO method. The experimentally obtained maximum MRR and minimum RLT and SR are 2.657 mm3/min, 7.9 µm, and 0.351 µm, respectively. The regression results showed that DNN+MRFO outperforms the RSM model. The achieved desirability at confirmatory analysis for RSM and DNN+MRFO are 0.844 and 0.921, respectively.

WEDM with different diameter wire electrodes on Inconel 718: Improved dimensional deviation, wire consumption and surface quality

Inconel 718, a rich nickel content alloy, has been widely adopted for high-temperature applications across industries. A recently explored non-conventional machining method, wire electrical discharge machining (WEDM), is suitable for machining these alloys. However, the dimensional inaccuracy, high consumption of wire tool electrodes and poor surface quality affects precision and productivity. This study aimed to investigate the effect of employing different wire diameters in WEDM and influence on performance characteristics such as the dimensional deviation, overcut, wire consumption, surface roughness, recast layer thickness, micro hardness, microstructural and metallurgical changes. For small wire diameters compared to large wire diameters, a significant reduction in the dimensional deviation and overcut is incurred. With average-sized craters, a surface machined using a small-diameter wire showed enhancement, decreased changes in micro-hardness, and lower recast layer thickness than a surface machined using a large-diameter wire. For the prediction of surface roughness, a model was developed considering wire diameter. In addition, wire consumption for smaller wire diameters is reduced, encouraging cost-efficiency, and solving problems with waste disposal. The Inclusion of smaller-diameter wires in WEDM has increased the precision with productivity, promoted reduction in the wire and workpiece waste, and has a lower environmental impact.

Multi-pass EDM process planning for the surface treatment of powder-bed-fusion AM CORRAX mold steel

Although it is time-consuming to perform multi-pass electrical discharge machining (EDM) processes, EDM is exceedingly feasible for processing the partially unmelt profile of Powder-Bed-Fusion additive manufacture mold steel. This study is based on the principle of removing three times the thickness of the recast layer and reducing the EDM processes depth. And then, the surface quality and the processing time with EDM passes are decreased by adjusting the EDM passes suggested by the machine builder. Secondly, reduction of four more passes and the predetermined depth of processing so that the total processing time can be reduced further. Finally, the efficiency is increased by more than 77% compared to machine builder’s processes, and the final surface roughness reaches the specification of 0.17 μm Ra. The HAZ and recast layer thickness are also reduced drastically and distributed uniformly. Therefore, a new version of the EDM process planning suitable for AM CORRAX mold surface treatment is proposed, and its processing efficiency and surface integrity are investigated.

Experimental Investigation on Micro-Electrical Discharge Machining process for heat treated Nickel-based Nimonic 80A

ABSTRACT Nimonic 80 A is a nickel-based alloy having diverse applications in aerospace, automotive, biomedical, and military sectors owing to its immense strength to weight proportion and resistance to corrosion at raised temperatures. As a result of the problems associated with its conventional machining, unconventional machining, in particular, EDM is preferred. Micro-machining has become a key attraction point for manufacturing organizations. This requires to have an understanding of the process in terms of the impact of control factors on the performance characteristics. In the prevailing experimentation, micro holes were drilled on a heat-treated Nimonic 80A plate. Current, pulse-on time and pulse-off time are considered as the control factors, whereas tool wear ratio and drilling rate are considered as the performance variables. The experiments were designed using RSM. ANOVA has been carried out and the SEM analysis of the drilled hole was performed for examining the quality of the holes. The measurement of the thickness of recast layer was performed. Copper and zinc, diffused around the micro-drilled area, were identified through the elemental composition of the drilled sample using EDX. Minimum tool wear ratio and the maximum drilling rate were obtained to be 0.78 and 0.77 mm/sec, respectively.

Surface characteristics and recast layer thickness analysis of µed machined Inconel 718 alloy with biodiesels

ABSTRACT µED-milling is a modern machining process for manufacturing precise microstructures on a wide variety of conductive materials without considering their mechanical properties. Using mineral oils as a dielectric fluid in µEDM causes a hazardous environment for the operator. This study attempts to identify the substitute for hydrocarbon oil during milling of Inconel 718 at various order of discharge energy. Neem and Sunflower biodiesels are chosen as dielectric fluids and a comparison was made in terms of response measures of EDM oil. Top (higher) order discharge energy offered a maximum MRR with EDM oil, Neem and Sunflower biodiesels. However, the EDM oil yielded a higher MRR than biodiesels due to its higher current conductivity and lower viscosity. The fine craters are achieved when lower-order discharge energy is used due to tiny sparks generated at machining gap. Neem biodiesel follows more closely with EDM oil than Sunflower biodiesel for all considered response measures. The contact angle of the machined surface with biodiesels is smaller than EDM oil attributed to the presense of broader craters in the surface. The recast layer thickness is increased by 92% and 44% with and Neem biodiesel than EDM oil.

Surface integrity analysis of machined surface of Ni-Ti shape memory alloy during wire spark erosion machining

PurposeThe purpose of this paper is to analyze the surface integrity, including recast layer thickness, surface crack density, X-ray diffractions study and microhardness for Ni53.49Ti46.51 shape memory alloy (SMA) during wire-spark erosion machining.Design/methodology/approachFour persuasive process parameters, that is, spark on time (SON), spark off time (SOFF), wire feed (WF) and spark gap voltage (SV), have been chosen for the current investigation. Efforts have been done to explore the effects of above said parameters on the machined surface of Ni-Ti SMA by embracing box Behnken design of response surface methodology (RSM). Cutting speed and ten-point mean roughness (Rz) has been taken into account as response variables. Analysis of variance test was also performed for both response parameters with the coefficient of determination (R2) 0.9610 for cutting speed and 0.9252 for ten-point mean Rz.FindingsThe recast layer thickness from 7.83 to 12.13 µm was developed near the machined surface at different parametric settings. The least surface crack density was found at the lowest value of ten-point mean Rz, while most surface crack density was identified at the highest value of cutting speed. The microhardness near the machined surface was increased by approximately 1.8 times bulk-hardness of Ni53.49Ti46.51 SMA.Originality/valueSome researchers have done a study on average surface roughness, but very few investigators concentrated on ten-point mean Rz. Surface crack density is an essential aspect of machined parts; other researchers have seldom reported it. The novelty of this research work is that the influence of SON, SV, WF and SOFF on cutting speed, Rz, recast layer thickness, micro-hardness and surface crack density proximate the machined surface while machining workpiece material.

Analysis of Particle Size and Concentration in Die Sinking Electric Discharge Machining.

Electric discharge machining with a powder mix dielectric is a promising technique to harden a work piece’s surface using electricity with a high energy density. The quality of the electrical discharge-machined surface is related to its surface integrity in which the surface’s roughness, residual stresses, micro hardness and surface micro cracks are some of the major factors. In this research, graphite powder was mixed in a dielectric with a particle size of 20 µm, 30 µm, and 40 µm, with the concentration of the graphite powder ranging from 2 g/L to 4 g/L. Moreover, the peak current and pulse time on were also coupled with an additive of graphite powder to investigate the effect on the surface quality, i.e., the recast layer thickness, micro hardness and crater depth as well as the material removal rate (MRR) and tool wear rate (TWR). A Box–Behnken design was employed to design the experiments and the experimental results revealed that the graphite powder size and concentration coupled with the electrical parameters (peak current and pulse time on) significantly influenced the recast layer thickness, micro hardness, crater size, MRR and TWR. The crater depth and micro hardness were maximized at a higher concentration and particle size, while the recast layer thickness was reduced with a higher gain size.

Optimization of hydroxyapatite powder mixed electric discharge machining process to improve modified surface features of 316L stainless steel

Traditional methods for producing 316L steel with a desired roughness and a uniform thin coating for sufficient bioactivity and long-term durability are highly difficult and require post-processing. Electric discharge machining (EDM) is a nontraditional process that can accomplish both machining and coating the surface concurrently. This study provides a thorough examination of the impacts of EDM process parameters on the machining responses, which are significantly necessary for processing 316L steel to reach its full potential. The nano-hydroxyapatite particles added EDM method is used to improve the machining and the surface responses. EDM process parametric optimization is conducted using Taguchi's design to achieve the lowest surface roughness of 2.04 µm and a recast layer thickness of 6.11 µm. As a machinability metric, the greatest material erosion rate (MER) of 20.64 mg/min is achieved. Current intensity, discharge period and hydroxyapatite amount are identified to be important predictors for MER, surface roughness and recast layer thickness. Scanning electron microscope with the energy dispersive X-ray spectrums and atomic force microscopic images validate the machined surface morphology, elemental compositions and surface topography. Errors of the confirmatory tests are less than 10%, showing that the projected solution sets by the grey wolf optimizer are highly accurate. The study shows a thin recast layer with both nano and micro-surface roughness formation, which have a great importance in biomedical applications.

Surface Integrity Analysis of Wire Electric Discharge Machining of Nitinol Shape Memory Alloy: A Literature Review

When nitinol is machined, quantitative details regarding the surfaces such as the surface crack density, utmost peak-to-valley heights, recast layer thickness and the mean peak-to-valley height among others offer the most appropriate features to consider in the integrity of the surfaces of machined nitinol. This quantitative information directs the integrity and the projected future performance of the machined nitinol in the components. Consequently, the research question of how to achieve optimal surface integrity of the machined nitinol is important. A literature review is conducted to study the surface integrity analysis of wire electrical discharged machined nitinol. In particular, published papers between 2007 and 2021 have been reviewed. Literature is explored concerning the method of analysis, parameters of research interest and the problems/issues arising from the literature. Diverse methods were employed to evaluate the surface integrity of nitinol after machining. Commonly, both mathematical optimization and microstructural characterizations are used to suggest ideas. Mathematical optimization has been in two broad perspectives, namely, experimental design-based methods such as orthogonal arrays, signal-to-noise ratios, Taguchi's utility and quality loss function, Box-Behnken design and response surface methodology. The non-traditional optimization schemes such as the differential evolution, multi-objective optimization based on ratio analysis and teaching learning-based optimization have been applied. For microstructural characterization, tools to evaluate the surface integrity of nitinol such as field emission scanning electron microscope and energy dispersive X-ray have been deployed. Parameters such as residual stress, geometric deviation, microhardness and profile accuracy are pursued to be optimized. It is known that various literature reviews in previous years have studied the surface integrity problem of nitinol using large-scale approaches. However, in this article, a brief review is prescribed and this work reveals how the surface integrity analysis of nitinol has been tackled in the literature.