Electroplating Research Articles

Morphology and Magnetic Properties of Ni Nanowires in Thin Film Anodic Alumina Templates

The features of the morphology and magnetic properties of Ni nanowire arrays have been studied. Aluminum oxide matrices are used as a template for electrolytic deposition of nanowires. The matrices are obtained by anodizing the aluminum films with a thickness of 2 μm that are formed on glass substrates by high frequency ion sputtering. Electrochemical deposition of the metal is carried out using direct and alternating currents. Morphology and microstructure studies show that the nanowire arrays are polycrystalline and have a branched dendritic structure due to the morphological features of aluminum oxide matrices. A relationship between the magnetization reversal patterns and the modes of electrodeposition of Ni nanowire arrays is established. The process of magnetization reversal of an array of this kind of structures is simulated.

Facile Synthesis of Metal/Carbide Hybrid toward Overall Water Splitting

The development of cost-effective and high-performance bifunctional catalysts for overall water splitting is crucial for achieving sustainable clean energy. In this study, a metal/carbide hybrid (NiFeMo/NiFeMoCx) was prepared through fast and facile cathodic plasma electrolytic deposition. Due to the synergistic effect between the metal and carbide, NiFeMo/NiFeMoCx exhibited high activity in both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER), with overpotentials of 230 mV and 60 mV at 10 mA cm−2, respectively. In addition, robust stability was demonstrated during the overall water splitting (1.52 V at 10 mA cm−2, with little degradation after 18 h of catalysis). This work provides a useful strategy for designing advanced water splitting catalysts for real application.

In situ Triggered Rich‐LiF/Mg Multifunctional Passivation Layer for Modifying the Anode Interface of All‐Solid‐State Lithium Metal Batteries

AbstractLithium (Li) is a promising anode material for all‐solid‐state Li metal batteries (ASSLMBs) due to its high energy density. However, the interface incompatibility of Li/solid electrolyte and uneven Li deposition induces the penetration of Li dendrites. Herein, a multifunctional rich‐LiF/Mg artificial solid electrolyte interphase (SEI) layer is constructed from a MgF2‐PVDF‐HFP film to passivate the Li anode and achieve effective inhibition of Li dendrites. Notably, the triggered LixMg alloys rivet the Li6PS5Cl (LPSCl) electrolyte and Li anode together well, producing satisfactory interface contact and reducing overpotential. The mechanism of LiF and LixMg alloys to enhance the stability of the Li/LPSCl interface is further elucidated by density functional theory (DFT). Moreover, the synergistic interaction of LiF with high interfacial energy and LixMg alloys with low diffusion barrier promotes uniform deposition of Li during plating/stripping and structural stability. Therefore, the modified Li‐symmetric cell exhibits ultra‐high critical current density (2.0 mA cm−2) and considerable cyclic stability (more than 1000 h at 0.5 mA cm−2). Remarkably, NCM//LPSCl//3% MgF2‐PVDF‐HFP@Li ASSLMBs exhibit considerable long‐term cycle stability (86.9% capacity retention after 100 cycles at 0.2 C). This work highlights the critical role of the intermediate passivating layer in mitigating side reactions and preventing Li penetration.

Comparison of Hardness by Electrolytic and Electroless Deposition of Nickel on Aluminium

Abstract The work deals with the hardness characteristic of substrates coated with nickel through two primary methods: electrolytic deposition and electroless Ni-P deposition. The optimised process parameters for both the process was determined by varying a particular parameter keeping the rest constant in order to obtain minimum crystallite size of Ni. The size of the crystallite were determined using Scherrer’s equation. The optimized combination of process parameter for electrolytic deposition is: 270gm/lt of Nickel Sulfate, 60gm/lt Nickel Chloride, 35gm/lt Boric Acid, current density of 90mA/cm2 bath temperature of 55°C. The optimized combination of process parameter for electroless Ni-P deposition: 34gm/lt Nickel Sulfate, 23 gm/lt Sodium Hypophosphite, 46 gm/lt of Lactic acid, 42 gm/lt of Sodium Citrate, pH 5.0 and bath temperature 85°C. The optimised deposition rate 22μm/hr. Micro-hardness (Vickers) tests were conducted on the coated samples with a 50 gf load. The cause for difference in hardness was due to buildup of residual stress during deposition of Nickel on the substrate(aluminium). The orientation and surface texture of the materials are determined.

Correlation between Electrolyte Concentration and Lithium Morphology during Lithium Bis(fluorosulfonyl)amide–Tetraglyme Electrolyte Deposition–Dissolution Reactions

Electrodeposition and chemical dissolution reactions of Li are strongly affected by the electrolyte concentration at the electrode surface. In this study, we investigated the processes involved in the formation of Li deposits at various electrolyte concentrations and different numbers of deposition–dissolution cycles. Growth of the deposits during the cycles was assessed using a digital microscope. The thickness of the fibrous layer was strongly dependent on the electrolyte solute–solvent molar ratio. The thickness of the fibrous layer increased as the number of cycles increased when the electrolyte solute–solvent molar ratio was low but decreased when the molar ratio was high. Temporal changes in the electrolyte concentration and in the diffusion layers near the electrode were identified using a laser interference microscope. The results led us to conclude that there are three fibrous Li deposit growth models that occur at different solvent–solute molar ratios.

Enhanced thermal performance of CeYSZ coating on Ni-based high temperature alloy with a unique Y-doped Al2O3 barrier layer via cathodic plasma electrolytic deposition

Cathodic plasma electrolytic deposition (CPED) has shown considerable potential in producing high-performance thermal barrier coatings (TBCs) for components operating in extreme thermal environments, such as gas turbines and aviation engines. However, the dendritic and porous structures greatly limited the use of CPED-coatings in some harsh environments. In this study, one Y-doped Al2O3 (Y/A) barrier layer was prefabricated before the deposition of CeO2 and Y2O3 stabilized ZrO2 (CeYSZ) thermal barrier coating using CPED. The results suggested that the prefabricated Y/A barrier layer can attenuate the plasma bombardment and promote the uniform discharge, resulting in the formation of a thinner gas film layer on the cathode surface, which significantly avoided the course dendritic defects and improved the density of the CeYSZ coating from 6.788 g/cm³ to 6.978 g/cm³. Consequently, the thermal insulation temperature of Y/A-CeYSZ coatings exceeded that of CeYSZ coatings by a factor of 1.3, and the thermal cycling performance at 1300 °C demonstrated a 52.5% improvement. This study provided a valuable method for the development of novel CPED TBCs.

Uranium electrolytic deposition with regenerable Se2− active sites at low cell voltage

The electrochemical extraction of uranium from wastewater represents an effective strategy for the sustainable supply of fuel and the protection of the environmental. However, the rational design of high-efficiency electrocatalysts remains a significant challenge, largely due to the lack of research on the structure–activity relationship. In this study, we developed a novel electrocatalysis based method for the extraction of uranium in solution, combining the redox of selenium (Se2-/Se4+) and uranium extraction. This method enables the high-efficiency extraction uranium in solution, even at relatively low cell voltages of 1 V. The Co3Se4-based electrocatalyst exhibits excellent UO22+ capture properties, endowing it with an electrolytic deposition capacity of 2264 mg g−1 at the concentration of 560 mg L−1 within 48 h. Even in a low concentration uranium solution (5 mg L−1), the extraction capacity can still reach 199.2 mg g−1. X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) revealed that the main active sites of Co3Se4 were renewable Se2- sites. The absorbed UO22+ can be spontaneously reduced to the unstable U(V) intermediate by reversible electron transfer, and then re-oxidized to (UO2)O2·2H2O in the presence of hydrogen peroxide (H2O2). The significant discovery provides a novel electrochemical medium, elucidates the mechanism of the uranium extraction process, and introduces a novel strategy for harvesting U from wastewater.

Features of cavitation wear of chrome electrolytic coatings

Cavitation wear is a pervasive phenomenon on water transport. The parts of ship propulsion system as well as the water-cooled surface of cylinder liners of high-speed ship diesels are subjected to cavitation attack. Bright chromium deposits are used to protect the water-cooled surface of liners. Nevertheless, the effect of cracks appearing in the electrolytic chrome coating upon depositing on the cavitation resistance of coating is still an open relevant problem. The goal of the study is to analyze the kinetics and mechanism of the destruction of the bright chrome electrolytic deposit under cavitation attack. The cavitation resistance of chrome electrolytic coatings after grinding and after polishing was studied. The chrome electrolytic coatings were obtained on the plates (90 × 30 × 7 mm in size) made of cast iron SCh21. The chrome was deposited on one side (90 × 30 mm) of the plate placed vertically by flow anodic jet chrome plating in standard electrolyte (kg/m3): chrome anhydride — 250; sulfuric acid — 2.5; trivalent chrome — no more than 5; trivalent iron ions — no more than 10. The electrolyte was prepared using distilled water of a single distillation. The parameters of depositing: electrolyte temperature is 50°C; the current density amounts to 60 A/dm2. Four samples cut from the same plate were used. The coatings on the first two samples were ground using the abrasive paper number 320. The coatings on the second pair of samples were first ground successively on the abrasive paper of different grit: 320, 500, 800, 1000, and 1200, and then polished on the cloth with GOI paste. The cavitation wear tests were carried out on a magnetostrictive vibratory rig in fresh water, the frequency and amplitude of the rig horn vibration was equal to 22 kHz and 28 μm, respectively. The spacing between the chrome-plated sample surface and the horn butt was 0.5 mm. The wear of the samples was evaluated by periodical weighing during testing. The wear of the ground samples turned to be significantly higher, than that of polished samples. The photographs of the surface after different duration of the cavitation attack show that the initial cracks formed on the coating during chrome plating are the centers of cavitation destruction. To reduce the negative impact of initial cracks on the cavitation resistance of the bright chrome electrolytic coatings deposited on the water-cooled surface of the cylinder liners of diesels it is shown expedient to include polishing in the technological process of depositing chrome coatings.

Wall sandwich panels with steel facings and PUR foam core under transverse loading: Experimental testing and numerical model calibration

Light weight panels are largely used for the envelope (wall assembly, roofing system) of different kind of buildings. Under extreme loading conditions, like external explosions, the walls may suffer extensive damage, under either positive or negative pressures. The study presented in the paper describes the results obtained on wall sandwich panels tested for transverse loading until complete failure. The panels are arranged as single span systems supported on side rails and loaded at the mid-span. After a quasi-linear response, the maximum bending capacity is reached. At this point, the panels have a sudden drop in capacity, associated with the rapid wrinkling of the face in compression. If the end fasteners have adequate resistance, catenary stage develops, and the ultimate capacity can be significantly higher than the peak bending capacity. Flexibility of the lateral restraints significantly influence the initiation of catenary action and the ultimate capacity of sandwich panels. Numerical models were calibrated using the structural analysis and design program SAP2000. This may allow professionals to integrate more quickly the wall models into the structural design even for extreme loading conditions.

Research on the Mechanism of Oxygen-Induced Embrittlement Fracturing in Industrial Electrolytic Nickel.

In this study, severe cracking occurred during an investigation of the direct hot rolling of industrial electrolytic nickel plates. To determine the cause of hot-rolling cracking, the microstructure phase composition was analyzed through the utilization of various techniques, including optical microscopy, scanning electron microscopy, electron backscattering diffraction, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS) and electron probe micro-analysis. The comparative microstructural analysis took place between specimens heat treated in atmospheric and vacuum environments. The characterization and analysis of the hot-rolled plates considered the crack microstructure and fracture morphology. It was shown that holes appeared along the large angular grain boundaries after annealing at 1100 °C for 8 h. Possible reason: In a high-temperature environment, the decomposition of residual additives in the electrolytic nickel releases oxidizing gases, which oxidizes the grain boundaries. The reaction with carbon diffused into the grain boundaries and produced carbon monoxide gas, which induced holes and severely reduced the grain boundary plasticity. The heat treatment time did not need to be very long for severe grain boundary degradation to occur. After severe cavitation, the electrolytic nickel was severely cracked at grain boundaries cracks due to a shear force, and brittle fractures occurred along grains with very low plasticity.

Properties and Applications of Supersaturated Metastable Alloys Obtained via Electrodeposition

Supersaturated alloys can exhibit superior properties and electrodeposition is a cost-effective and versatile technique to produce them. In this review, the chemical, mechanical and structural properties of supersaturated alloys are discussed, and connections with metallic glasses and high entropy alloys are also exposed. After discussing mechanisms causing supersaturation in electrodeposited alloys, an overview of the most important electrodeposited metastable alloys is provided, showing that they are mainly used as protective coatings able to improve corrosion resistance and tribological performance of a large variety of industrial components. Composition of the electrolytic baths and deposition parameters are also considered and discussed.

OREATE as a High Yield and Purity Electrochemical Process for Transition and Rare Earth Metal Recovery

Developing a process that can consistently convert transition and rare earth metal oxides to chemically pure metals in near quantitative yield will have significant impact in many levels, from fundamental science to national security-related applications. Traditional separation methods of lanthanides and actinides from aqueous media have been based on liquid-liquid extractions that have proven to be quite efficient, though they are expensive and require complex engineering. Likewise, separation by pyro-chemistry provides a good recovery performance but requires the use of high temperatures that adds technological difficulties to the process. An alternative method that has grown interest in the last few years is the utilization of the difference in the metals’ reduction potentials from ionic state to metallic state. However, this electrochemical approach requires more negative reduction potentials than hydrogen evolution, which requires a very challenging control of their electrolytic deposition onto solid cathodes.In recent years, our team at LANL has been working on the development of OREATE (Oxide Reduction by Electrochemical Amalgamation and Thermal Extraction). OREATE is a holistic electrochemical approach that involves an initial step wherein the metal oxide is dissolved and chlorinated into an acidic medium. The dissolved metal cation is then electrochemically amalgamated via reduction using a mercury pool cathode. Finally, mercury's high vapor pressure allows an easy thermal extraction process to obtain the metal. From the conceptual perspective and preliminary results, the OREATE process appears easier and simpler than traditional separation methods and is suitable for small- and large-scale preparation of high purity metals.The results obtained using Cerium (Ce) as a surrogate metal demonstrated near quantitative yield of the electrochemical amalgamation (yield > 99%), almost complete mercury recovery during the thermal extraction (Hg recovery > 99.5%), and high purity of the Ce metal product (purity > 99%). Moreover, a variety of system parameters such as the pH of the buffered solution, concentration of cerium, reduction potential, and temperature were explored to evaluate the effect that the scaling up of the OREATE process may have on reaction rate, current efficiency, process yield, and temperature management.

Iron Production By Molten Sulfide Electrolysis

With urgency and incentives to cut CO2 emissions, alongside increasing demand for steel, there is a need for technologies that use solely electricity for iron ore reduction, eliminating the role of carbon as a reductant. Herein, we propose the electrolytic production of liquid cast iron using a novel sulfide route, molten sulfide electrolysis (MSE). The process operates using sulfide chemistry and an inert anode. Sulfides are well known from non-ferrous metallurgy1 and the exclusion of oxygen supports a virtual elimination of green-house gases(GHG) emissions from the reduction step. The electrolytic decomposition of iron sulfide into iron and elemental sulfur gas operates in a multi-component molten sulfide electrolyte. The underlying thermodynamics suggests the absence of trivalent iron species (Fe3+) in such conditions, supporting the reduction of only divalent iron (Fe2+) and reducing the energy need proportionally, as compared to other oxide-based routes. Iron sulfide deposits or tailings, as well as conventional iron oxide ores after sulfidation2 are some of the suitable feedstocks for MSE.Both thermal only, and galvanostatic electrochemical experiments were carried out on electrolyte droplets (~200mg) in a thermal imaging furnace, to confirm the electrolytic deposition of Fe and the evolution of sulfur in a 2-electrode set-up. Faradaic efficiency estimates based on mass-loss measurements – i.e. with respect to gaseous sulfur anodic evolution – are of the order of 90%. Key electrochemical attributes of MSE to be reported include impedance measurement at various fixed DC potentials, measurements at various current densities up to 2A/cm2, and the role of the total charge passed, to highlight the potential limitations observed in such an experimental set up. Characterization of the electrochemical deposits are also presented.

Crushing behavior and energy absorption of steel-GFRP-foam sandwich structures under quasi-static compression: Experimental and theoretical study

To overcome the poor energy-absorbing efficiency of existing layered panels, three kinds of novel steel-glass fiber reinforced polymer (GFRP)-foam sandwich structures composed of two steel face sheets and GFRP-foam composite cores were proposed in this paper. The effect of the composite core thickness and GFRP lattice configuration on the energy absorption performance for sandwich structures was studied through quasi-static crushing tests. Considering the role of steel face sheets, a theoretical prediction model was derived to calculate the initial absorbed energy for all types of sandwich panels. Parametric studies were carried out to investigate the influence of five different variables (axial compressive load, steel sheet thickness, GFRP web thickness, GFRP and foam compressive modulus) on the overall energy dissipation for each kind of composite panel. Test results indicated that both the thicker core component and double-layered dislocation GFRP layout could effectively promote the energy consumption property of all the steel-GFRP-foam structures, and the steel face sheet played a crucial role in the proposed sandwich panels due to its excellent absorbed-energy capacity per volume and exceptional ductility. Theoretical results demonstrated that the equivalent energy-absorbing formula was desirable to be used to assess the crushing resistant behavior of each sandwich structure. Parametric analysis results showed that a larger axial compressive load was able to improve the structural initial energy absorption, but the increase of four other structural parameters, especially the thickness of the front (rear) steel sheet, could weaken such an identical performance.

Analysis of Opaque, Peel-Off and Flex Rejects in the Electro Plating Process Using the Six Sigma Dmaic Method

The modern manufacturing industry is faced with increasing pressure to achieve high levels of quality while remaining efficient in its production processes. One of the challenges faced by PT. Plating services in electroplating production have a high reject rate, which can cause increased costs and have a negative impact on the company's reputation. PT. Jasa Plating in the production process still has a high number of rejects, the rejects are dominated by opaque, peel-off and spots. PT. Plating services for each production contribute a high average of 2% defects per day, DPMO 20,000 and Sigma value 3.55. Quite a few rejections resulted in a decrease in turnover and increased production costs. The costs incurred due to these rejects are an average of Rp. 1,268,593 per day and an average of Rp. 35,698,907 per month as a result of data collection from January – September 2023. In this business process, this is very detrimental for the company. The aim of this research is to suppress blurry rejects, peel-offs and spots in the electro plating process at PT. Plating Services. The steps taken in conducting research include: identification stage, data collection and processing, analysis and recommendations for improvement, and conclusions. The method used in this research is the Six Sigma DMAIC (Define, Measure, Analysis, Improvement, Control) method. Through analysis, you can find several factors that cause high reject rates, including operational errors, discrepancies in the production process, or raw material quality problems. After implementing the improvement plan, then evaluate the results. This can include re- measuring the DPMO, analysis of the resulting products to see a decrease in reject rates, and comparisons between before and after implementing improvements. From the comparison results after the repairs were carried out, the data before the repairs were carried out, the NG amount was 1.99%, the DPMO was 6,646 and the Sigma value was 3.98. After improvements to NG 0.84%, DPMO 2,791 sigma value 4.28. Factors causing high levels of blurring, peel-off and spots, namely insufficient or excessive cleaning of the metal surface before the electroplating process, can cause problems such as peel-off. Contamination of the electroplating solution by foreign materials can cause blurring and flecks in the final layer. Machinery or equipment that is not properly calibrated, or experiences wear and tear, can produce products that do not meet standards. Variations in temperature, time, or electric current in the electroplating process can produce inconsistent coatings. Carefully monitor and control process-parameters to ensure stability.

The Enhancement Discharge Performance by Zinc-Coated Aluminum Anode for Aluminum–Air Battery in Sodium Chloride Solution

The main drawback of seawater batteries that use the aluminum (Al)–air system is their susceptibility to anode self-corrosion during the oxygen evolution reaction, which, in turn, affects their discharge performance. This study consist of an electrochemical investigation of pure Al, 6061 Al alloy, and both types coated with zinc as an anode in a 3.5% sodium chloride (NaCl) electrolyte. The electrolyte solution used for the deposition of zinc metal contained citrate, with and without EDTA as a complexing agent. Subsequently, the performance of the anode was tested in a seawater battery, using a carbon@MnO2 cathode and a 3.5% NaCl electrolyte. The performance of Al–air batteries has been significantly enhanced by applying a process of electrodepositing zinc (Zn) with a citrate deposition electrolyte solution in both pure aluminum and alloy 6061. The performance of the battery was further enhanced by adding EDTA as a chelating agent to the citrate-based electrolyte solution. The Al–air battery with aluminum alloy 6061 with Zn electrodeposition with an additional EDTA as the anode, carbon@MnO2 as the cathode, and NaCl 3.5% solution as the electrolyte has the highest battery performance, with a specific discharge capacity reaching 414.561 mAh.g−1 and a specific energy density reaching 0.255 mWh.g−1, with stable voltage at 0.55 V for 207 h.

Wear performance of MoS2 doped Al2O3 CPED coatings on TC6 titanium alloy

The innovative work presented in the paper focused on microstructures and wear performance of MoS2 doped Al2O3 coatings on TC6 alloy. Nano- and micron-sized MoS2 particles doped Al2O3 coatings (n and m-MoS2/Al2O3 coating) were fabricated on TC6 alloy via cathodic plasma electrolytic deposition (CPED) technique. The microstructures and compositions of the coatings were characterized, the tribological behaviors were tested, and doping mechanism of MoS2 particles was discussed. The results showed that, doped coatings were composed of α-Al2O3, γ-Al2O3 and MoS2. The doping of MoS2 particles promoted the transformation from γ-Al2O3 to α-Al2O3 during CPED process, and increased the compactness and crystallinity of doped coatings. The friction coefficients of TC6 alloy, Al2O3 coating, n-MoS2/Al2O3 coating and m-MoS2/Al2O3 coating were about 0.7, 0.6, 0.55 and 0.45 in sequence, and the wear rates of n-MoS2/Al2O3 coating and m-MoS2/Al2O3 coating were about 75 % and 58 % of Al2O3 coating. MoS2 particles played the role of lubrication and contributed to improving wear performance of doped coatings, both friction coefficients and wear rates were declined, and micron-sized MoS2 particles presented better wear performance than nano-sized particles.

Low Current Density Cathode Plasma Electrolytic Deposition of Aluminum Alloy Based on a Bipolar Pulse Power Supply

The present paper reported a novel bipolar-pulse cathodic plasma electrolytic deposition (BP-CPED) technique with a low current density. This newly developed CPED technique can break down the barriers of the existing CPED technique with higher current density. In this report, ceramic coatings were successfully prepared on aluminum alloy via the BP-CPED technique in an aqueous carbamide-based electrolyte. Data recording results in the reacting process show that there is the current density of the cathode below 0.15 A/cm2 and that of the anode below 0.035 A/cm2, which approximately reaches the level of conventional MAO technique. Interestingly, the addition of PEG into the electrolyte can further reduce the current density and effectively improve the coating quality. The kinetic of the BP-CPED process was discussed based on the evolution of current density/voltage-time curves and spark discharge phenomena. SEM observations illustrate that BP-CPED coatings possess a typical porous-surface feature. XRD analysis indicates that the coating was mainly composed of Al2O3 and Al4C3. Al2O3/Al4C3/ZrO2 composite coatings fabricated after Zr-doping reflected the successful Zr-incorporation into the coating, which demonstrated that the BP-CPED technique can be used to design the coating composition by the doping modification. The direct pull-off and thermal shock tests confirmed that new BP-CPED coatings obtained under the cathodic plasma discharge have excellent bonding strength. It is possible that this novel BP-CPED technique can provide a promising choice in developing the large-area CPED surface treatment for the industrial application.

The effects of electrolyte composition and deposition voltage on the copper-nickel alloy micropillars fabricated by Jet ECD

With the rapid development of micro electronic component technology, higher requirements are put forward for high performance and high precision manufacturing process. In this paper, copper-nickel alloy micropillars were manufactured by jet electrochemical deposition (Jet ECD) technology with high deposition rate, aiming to provide an effective material and process solution for the manufacture of micro-thermocouples and other components. By optimizing the process parameters such as electrolyte composition, pH value and deposition voltage, the homogeneous deposition of copper-nickel alloy micropillar was realized. The cross-section morphology and elementary composition of the deposition micropillars were characterized in detail by using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results show that the adjusted formula and process parameters can stably manufacture copper-nickel alloy micropillars with a nickel-copper ratio (close to 0.8), and compact, void free microstructure.

Prediction of surface roughness in duplex stainless steel face milling using artificial neural network

Prediction of surface roughness in duplex stainless steel face milling using artificial neural network