Spray Parameters Research Articles

A U-shaped spray device on a front boom-type roadheader for dust suppression in a metro tunnel

The application of the cantilever tunneling method in urban metro tunnel constructions has been gradually promoted. High concentration of dust will be produced near the working face when a boom-type roadheader is used to excavate a small and narrow metro tunnel in hard rock. If not controlled in time, high concentration of dust will escape in the working wells, the air in cities will be polluted and the health of residents will be affected. To maintain the sustainable development of cities, a U-shaped dust suppression device with optimized nozzle arrangement installed at the front end of the boom-type roadheader is proposed in this study. Firstly, the atomization characteristics of four different types of nozzles were analyzed by an indoor model test. The optimum nozzle is determined to be a fine solid conical nozzle with a diameter of 1.6 mm. Then, the dust diffusion law in the core dust producing area under the action of an air compressor is analyzed based on the discrete phase model of computational fluid dynamics; the influence of the parameters of the complete spray device on the performance parameters of the droplet field is discussed in detail based on the Taylor analogy breakup simulation method. The results show that when the spray pressure is 8 MPa and the number of nozzles is 11, the formed droplet field has the best encapsulation and the high concentration droplets account for 77.36%. Finally, the device is applied and verified on site. The test results show that the maximum total dust suppression efficiency in the tunnel reaches 81.48%, the maximum respirable dust suppression efficiency reaches 81.51%, and the dust suppression efficiency at other monitoring points is also above 70.41%.

Parametric investigation on the close-loop R410A flash spray system for high power electronics cooling under low temperature

For high power density electronics, flash spray cooling is one of the most effective ways of dissipating heat at safe working temperature. Spray parameters exert significant influences on the heat transfer capacity. This paper conducted an experimental investigation to explore the influences of spray chamber pressure, mass flow rate and subcooling degree on the cooling capacity on a flat heated surface in a spray cooling cycle using R410A as the working fluid. The results indicated that the initial increases in spray chamber pressure, mass flow rate and subcooling degree all improved the heat transfer performance. The best cooling performance was achieved once these parameters reached their optimal values; those were 0.57 MPa, 4.9 g/s and 5 °C respectively. The subsequent increase of them deteriorated spray cooling heat transfer, decreasing critical heat flux and heat transfer coefficient while increasing surface temperature. The main reasons responsible for the heat transfer were related to the atomization performance of flash spray affected by the spray parameters. The critical heat flux and maximum heat transfer coefficient yielded on a simple flat copper surface achieved 300 W/cm2 and 550 kW/(K m2) while surface temperature was maintained below 30 °C under the optimal spray parameters.

Microstructure and Tribological Properties of Fe-Based-Al2O3-B4C Composite Coatings Prepared by High-Velocity Arc Spraying

Fe-based-Al2O3-B4C coating was prepared on the low-carbon steel substrates using high-velocity arc spraying. The effects of voltage, current, and distance on the porosity and microhardness of the coating were studied by an orthogonal test, and the optimum spraying parameters were determined. The microstructure and properties of Fe-based-Al2O3-B4C coatings prepared under optimum process parameters were characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), microhardness and friction wear tester. The results showed that the optimum process parameters were a spraying voltage of 41 V, a spraying current of 200 A, and a spraying distance of 150 mm. The porosity was 2.24 ± 0.32%, and the microhardness was 1543 ± 145 Hv0.1, which was 8 times that of the substrate. Under the same load of 4.2 N and varying sliding speeds of 500 t/min, 750 t/min, and 1000 t/min, the coefficient of friction of the coating was less than that of the low-carbon steel, and the wear rate of the coating was 65%, 70%, and 63% lower than that of the low-carbon steel, respectively. The main wear mechanism of the coating was material spalling, accompanied by slight oxidative wear and abrasive wear.

Research on Optimizing Spray Parameters for Cr3C2 - NiCr Coating Created on Alloy Steel by Plasma Spraying Technique

Research on Optimizing Spray Parameters for Cr3C2 - NiCr Coating Created on Alloy Steel by Plasma Spraying Technique

Experimental Study of the Droplet Deposition Characteristics on an Unmanned Aerial Vehicle Platform under Wind Tunnel Conditions

Unmanned aerial vehicles (UAVs) are widely used in field pesticide spray operations due to their wide applicability and high operational efficiency. However, their high spray height and fine pesticide droplets lead to a greater risk of drift and likely different droplet deposition outcomes compared to the expectation. So far, most of the previous studies have used direct field methods on UAVs’ droplet deposition characteristics and there have been few carried out in wind tunnels. Thus, in this paper, a simulated UAV platform equipped with TeeJet 80-015 VP fan nozzles was utilized to study the droplet deposition characteristics in a wind tunnel. The droplet deposition amount and drift potential reduction percentage (DPRP) under different spray parameters were obtained. The results showed that when the rotor was open, the deposition amount in the target area increased by 2.6 times and the drift deposition amount decreased by 7.3 times when spraying tap water at 3 m/s wind speed and 3 bar pressure. Faster wind speeds led to greater drift deposition amounts and a lower DPRP, but higher pressures resulted in greater drift deposition amounts and a larger DPRP. The 30 g/L PEG-20000 solution has a higher droplet size and smaller relative droplet spectrum width RS, resulting in the deposition amount in the target area increasing by 9.13% on average and the drift amount decreasing by 24.7% on average, and it can be used as an anti-drift additive when needed. The research results can provide reference and technical support for UAV wind tunnel tests and field operation specifications.

Impacto da altura de voo de drone pulverizador no espectro de gotas em café de montanha

ABSTRACT Weather conditions and sprayer operating parameters influence spray quality. Unmanned aerial vehicles are considered a modern, useful, and very efficient technological tool in the application of pesticides, as they carry out punctual spraying, and reduce environmental and public health problems. The objective of this study was to characterize the spraying quality carried out with an unmanned aerial vehicle as a function of flight height and target position in a coffee plantation in a mountainous region. Three flight heights (2.5, 3.0, and 4.0 m) were used, and the targets were placed at the top and bottom of the plant. For each plant, six water sensitive papers were placed on top of the plant and six were placed at the bottom. CIR 1.5 software was applied to determine the coverage percentage, drop density, volume median diameter, volumetric diameter corresponding to 10 and 90%, numerical median diameter, and relative amplitude. The results showed that the flight height only influenced the parameters of the volumetric diameter corresponding to 10% of the volume, numerical median diameter, and coverage percentage. The target position on the canopy influenced all the evaluated spraying parameters. In mountainous coffee plantations, the spraying system using unmanned aerial vehicle spraying is more efficient for the lower part of the plant.

TiO2 Photocatalytic Ultrafiltration Membrane Developed with Suspension Plasma Spray Process

The suspension plasma spray process was used to fabricate photocatalytic ultrafiltration membranes for potential water and wastewater treatment applications. An aqueous suspension of 30 wt.% titanium dioxide with an average individual particle size of around 30 nm was used as feedstock material. The spray parameters, such as suspension solid content, suspension feed rate, and spray distance, were optimized using an Ar/H2 plasma to retain a fraction of unmelted feedstock nanoparticles as the source of fine pores in the membrane microstructure. The microstructure, porosity, phase composition, and pure water permeability of the membranes were characterized comprehensively. The average pore size of the membrane was around 40 nm, which was very close to the particle size of the pristine titanium dioxide powder. The membranes demonstrated a high water permeability between 2000 and 7200 L m−2 h−1 bar−1, which was inversely proportional to the thickness. They also exhibited significant photocatalytic activity under visible light.

Spray Cooling as a High-Efficient Thermal Management Solution: A Review

As one of the most promising thermal management solutions, spray cooling has the advantages of high heat-transfer coefficient and maintaining a low temperature of the cooling surface. By summarizing the influential factors and practical applications of spray cooling, the current challenges and bottlenecks were indicated so as to prompt its potential applications in the future. Firstly, this paper reviewed the heat-transfer mechanism of spray cooling and found that spray cooling is more advantageous for heat dissipation in high-power electronic devices by comparing it with other cooling techniques. Secondly, the latest experimental studies on spray cooling were reviewed in detail, especially the effects of spray parameters, types of working fluid, surface modification, and environmental parameters on the performance of cooling system. Afterwards, the configuration and design of the spray cooling system, as well as its applications in the actual industry (data centers, hybrid electric vehicles, and so on) were enumerated and summarized. Finally, the scientific challenges and technical bottlenecks encountered in the theoretical research and industrial application of spray cooling technology were discussed, and the direction of future efforts were reasonably speculated.

The importance of individual spray properties in performance improvement of a urea-SCR system employing flash-boiling injection

The appropriate mixing of a urea–water solution (UWS) with exhaust gases in a selective catalytic reduction system is crucial to efficiently reduce nitrogen oxides and diminish the deposition of liquid wall film. One of the methods to enhance the mixing of the UWS with the exhaust gases is a flash-boiling injection. Its positive effect has been linked with a reduced Sauter mean diameter (SMD) and improved evaporation, but the flash boiling influences all the spray parameters. For low-injection-pressure cases, the spray angle generally increases, and spray-tip penetration reduces. Moreover, the reduction of the droplet size is not manifested only by reduced average droplet diameter such as SMD, but also the shape of the droplet-size distribution is changed when the injected liquid is superheated. It has not been evaluated which of these factors is the most important. It is also unknown whether the synergy between these factors is an essential element. In this study, we aim to fill these gaps and provide the numerical analysis of the influence of individual parameters of urea–water solution sprays on the exhaust system’s performance, with particular reference to the changes caused by flash boiling.It was found that none of the spray parameters influenced by the flash boiling could alone explain the mixing enhancement. Nevertheless, the alteration of the droplet size distribution led to the highest simultaneous reduction of wall film and improvement of ammonia distribution uniformity. However, the most substantial drop in the wall film formation was achieved when the spray angle was increased.The results led to the conclusion that the most positive effect of the flash boiling results from the combination of all of the considered parameters, with the most significant contribution coming from the reduced droplet size.

Macroscopic spray characteristics and internal structure studies of natural gas injection

The macroscopic spray characteristics and internal structure of a highly expanded compressed natural gas (Methane; CH4) spray were experimentally and numerically investigated. The spray jet characteristics were analyzed under various pressure ratios (PR), defined as the ratio of the methane injection pressure to the ambient pressure. The spray characteristics and shockwave structures were investigated using Schlieren imaging. The novelty originates from comparing the methane spray development and shockwave parameters under low PR (4 < PR < 9) conditions. The investigation included an evaluation of the effect of choking phenomena on gas flow at different PRs by changing the methane injection pressure. The results showed that a high injection pressure did not improve the spray tip penetration but increased the choking phenomenon in methane flow in the near-field region. This phenomenon is a key factor that strongly influences the shockwave structure and leads to 3.5% longer injection duration and at least 13% increase in the spray volume and area before entering the fully developed region of the Mach disk. With respect to the Mach disk parameters, a PR change from 6 to 9 enhanced the Mack disk height by at least 13.5% and its width by at least 29%. Increasing the Mach disk width with PR increased the methane near-field angle of the spray by at least 29%, triple-point angle by at least 29%, and spray width at the triple point by at least 29% because of the larger radial gas spray development. Overall, the comparison of the macroscopic spray characteristics and Mach disk parameters showed that the macroscopic spray parameters were almost similar despite the changes in the PRs. In contrast, the Mach disk parameters (height, width, and triple point angle) and variations in the methane spray field were larger than those in the macroscopic spray parameters. In addition, the simulation results were used to analyze the energy conservation and transfer conversion efficiencies of the gaseous injection system. The same increase in PR led to greater energy transfer and conversion efficiencies by 0.05% and 6.7%, respectively, which adversely affects charge mixing in the intake manifold. Strong air turbulence is required to enhance the charge-mixing mechanism and achieve a homogeneous fuel-air mixture. Therefore, the choking phenomenon requires more attention when implementing gaseous injection systems for internal combustion engines.

Influence of spray parameters on particle deposition behaviour, microstructure, phase constitutions, and mechanical properties of high velocity oxy-fuel sprayed WC-Cr3C2-Co coatings

To optimise spray parameters for fabricating well-bonded and less decarburised coatings, the morphologies and cross-sectional microstructures of powders and splats, in addition to the microstructure, phase constitution, and mechanical properties of high-velocity oxy-fuel (HVOF)-sprayed WC–Cr3C2–Co coatings were systematically investigated. Significantly influenced by spray parameters, splat morphologies vary from ellipsoids to well-flattened pies with some ejectors or stripes on their periphery and a splat/substrate interface with good contact. Splat microstructures vary homogeneously from a minimal hard phase to non-uniform structures with some dense surface layers and smoothly outlined hard phases or to non-uniform structures with rough surfaces and angular hard phases. The coating microstructure evolves from a non-lamellar structure with many pores to a lamellar structure with a well-contacted interface and a smooth surface hard phase. The coatings mainly consist of the WC hard phase and a small fraction of decarburised and amorphous phases, in addition to Co, Cr3C2, Cr7C3, Cr2O3, and Cr2O5. Porosity and WC retention index vary from 0.89 ± 0.11 to 2.32 ± 1.75% and from 84.68 to 94.48%, respectively. Microhardness, elastic modulus, fracture toughness, adhesive strength, and wear rate of the coatings vary from 7.03 ± 0.64 to 11.96 ± 0.94 GPa, from 77.64 ± 13.77 to 244.73 ± 65.75 GPa, from 1.23 ± 0.1 to 2.66 ± 0.66 MPa m1/2, from 18.54 ± 1.21 to 63.84 ± 8.01 MPa, and from 1.38 ± 0.32 to 3.54 ± 0.79 × 10−2 mg/(N⋅m), respectively.

Model construction and validation of airflow velocity attenuation through pear tree canopies.

To investigate the airflow velocity attenuation inside pear tree canopies and the factors that influence its effect on air-assisted spraying, the relationship between the resistance of the canopies to airflow and airflow velocity inside the canopies was determined. At the same time, the theoretical model of airflow velocity attenuation in the canopy was constructed, in which the velocity attenuation factor k and the incoming velocity were the model input values, and the airflow velocity in the canopy was the model output value. Then, experimental verification of the theoretical model was completed. The determination test of airflow velocity inside canopies with three leaf area densities revealed that the error range between the established theoretical model and the experimental airflow velocity inside the pear tree canopy was 0.11-1.25 m/s, and the mean size of the model accuracy was 83.4% under various working conditions. The results revealed that the region from a depth of 0m to 0.3m inside the canopy was the rapid attenuation area of the airflow and that from 0.3m to 0.9m was the low attenuation area. Furthermore, they revealed that high-speed airflow could strongly disturb the outer branches and leaves, greatly changing the windward area of the canopy blades and thus affecting the accuracy of the model. By introducing a dynamic parameter of the canopy leaf windward area for model correction, the R2 of the model was above 0.9. Finally, validation of the model was performed in an air-assisted spraying operation in an orchard. This study can provide a theoretical basis for the regulation of airflow parameters of air-assisted spraying of pear trees.

Insights on metallic particle bonding to thermoplastic polymeric substrates during cold spray

Metallization of polymers using cold spray technology has reached wide consideration in recent years. However, an effective modeling approach to address the deposition phenomena able to assess bonding formation in polymer metallization is still lacking. This study aims to develop a finite element model to simulate the solid-state deposition of metallic particles on thermoplastic polymeric substrates. Single copper particle impact on the Polyether Ether Ketone substrate was modeled using the coupled Lagrangian–Eulerian approach. Emphasis was given to the polymer material properties and substrate thermal history to account for the sensitivity of the physical and mechanical properties of polymers to temperature. Experimental coating depositions were performed to select an optimized set of spray parameters while single-particle impact tests were conducted for model validation. The substrate temperature was measured using an infrared thermal camera and was used to model the sub-surface temperature gradient during gas spray exposure. The proposed numerical model is shown to be capable of predicting various impact features includi mechanical interlocking and the effect of particle velocity fluctuations and temperature gradients on the extent of bonding. Substrate heating was found to have a distinct effect on the correct prediction of particle bonding. The proposed model enables tuning the appropriate processing conditions for successful copper particle adhesion on PEEK polymeric substrates.

The influence of selected plasma spraying parameters on microstructure and porosity of molybdenum coating

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Spray Characteristics and Parameter Optimization of Orifice Arrangement for Micro-Sprinkling Hoses

The spraying width and uniformity coefficient are important for the design of a micro-sprinkling hose. In this study, experiments were conducted on the water application intensity distribution for an individual orifice and multiple groups of orifices under three different working pressures (41, 69 and 103 kPa). In the test of an individual orifice, the spraying angles varied from 40° to 90°. The results showed that the water application intensity distributions of an individual orifice were well fitted by a two-dimensional Gaussian distribution. Further study indicated that the bimodal Gaussian distribution model performed well on tracking the two-dimensional features of the water application intensity distribution, with the determination coefficient R2 &gt; 0.90 and the standard root mean square error NRMSE &lt; 30%. It was revealed that the fitting parameters of the two-dimensional Gaussian distribution model had physical meaning and were directly related to the strength and location of the water application intensity distributions. Based on the analysis of these fitting parameters, it was found that the water application intensity distribution of an individual orifice was affected by the pressure, spraying angle and orifice area, among which the spraying angle was the most sensitive factor. By establishing a linear relationship between the fitting parameters and the spraying angles, the water application intensity distribution of an individual orifice for any spraying angle could be predicted by the Gaussian model. Therefore, the water application intensity distribution of multiple groups of orifices could be calculated by overlapping the water application intensity distributions of the individual orifices. The Monte Carlo method was used in this study to determine the maximum spraying width and uniformity coefficient by generating different groups of orifice arrangement for micro-sprinkling hoses. Eventually, the optimized orifice arrangement was recommended for the better design of micro-sprinkling hoses.

Characterization of spray parameters and flame stability in two modified nozzle configurations of the SpraySyn burner

One of the key parameters for spray-flame synthesis of nanoparticles with defined properties is the temporal flame stability. Flame pulsation and consequently flame stability strongly depend on spray characteristics (e.g., droplet sizes and velocities), which are directly influenced by the nozzle geometry. This influence is analyzed in this work. For this purpose, the flame stability of the SpraySyn burner (Schneider et al., Rev. Sci. Instr. 2019) with different nozzle geometries is investigated experimentally. Phase-Doppler measurements and high-repetition-rate chemiluminescence imaging are used to investigate spray formation and flame stability at several heights above the burner for two different liquids and two dispersion-gas flows. The converging geometry of the modified nozzle leads to overall smaller droplets and a narrower droplet-size distribution, presumably increasing the flame stability by enhanced evaporation and less interaction between the pilot flame and remaining large liquid lumps. The flame active time and the coefficient-of-variation are considered as two parameters to evaluate flame stability. Compared to the previous SpraySyn configuration, higher flame active time and lower values for the coefficient-of-variation are observed, indicating a more stable flame in this nozzle configuration.

Effects of Catalyst Composition, Loading, and Spray Parameters on the Performance of Unitized Regenerative Fuel Cell Membrane Electrode Assemblies

Proton exchange membrane unitized regenerative fuel cells (PEM-URFCs) combine the ability to both produce power (in fuel cell mode) and generate fuel and oxidant (in electrolysis mode) from the same cell. Compared with discrete fuel cell and electrolyzer systems, URFCs provide the potential for lower mass, volume, and cost. The composition and structure of the bifunctional oxygen catalyst layer (CL), which facilitates the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) at the same electrode, significantly affects performance and stability, particularly given the wide potential differences and different mass transport phenomena involved under operation in fuel cell or electrolysis mode. We previously showed bimetallic nanoframes provide bifunctional oxygen electrocatalysts with significantly higher activity compared with monometallic structures, evaluated using a rotating disk electrode configuration.1 Here, we investigated the effects of the oxygen CL composition, loading, and spray parameters on the performance of URFC membrane electrode assemblies (MEAs). Pt black and IrO2 catalysts were combined at different ratios and deposited at different mass loadings. Catalyst layers were sprayed directly onto membranes using an ultrasonic spray system. Within ultrasonically sprayed catalyst layers, higher spray rates resulted in improved fuel cell performance. Higher catalyst loadings improved both fuel cell and electrolyzer performance, but reached a region of diminishing returns at higher loadings. The ratio of the ORR catalyst (Pt) to the OER catalyst (IrO2) modulated the performance in both fuel cell and electrolyzer modes. Different catalyst ratios influence the catalyst utilization at higher loadings. The comparison of URFC performance at same Pt or IrO2 loadings indicates that in addition to the active catalyst itself, the non-catalytically active component influences MEA performance. This result is in line with our previous evaluation of synergistic effects of Pt and IrO2 within rotating disk electrode measurements1 and supports that in addition to the significant effects of catalyst material structure on performance, the electrode structure plays a critical role in fuel cell and electrolyzer performance in URFC MEAs. Repeated switching of URFC MEAs between fuel cell and electrolysis modes indicates that reasonable performance is maintained over the initial cycles within our single cell test configuration. References Godínez-Salomón, F.; Albiter, L.; Mendoza-Cruz, R.; Rhodes, C.P. Bimetallic Two-dimensional Nanoframes: High Activity Acidic Bifunctional Oxygen Reduction and Evolution Electrocatalysts. ACS Appl. Energy Mater. 2020, 3, 2404-2421. http://dx.doi.org/10.1021/acsaem.9b02051

Synthesis and Formation Mechanism of Metal Oxide Compounds

In this work, the influence of the technological parameters of the detonation method on the formation of metal oxide compounds on the basis of titanium was investigated. The aim of the work was to investigate the method of the effective control of the phase composition and microstructure of titanium-based coatings during detonation spraying. The main parameters that varied in detonation spraying were the volume of filling the detonation barrel with explosive mixture and the oxygen/fuel ratio. The mechanism of formation of the gradient structure of coatings based on metal oxide compounds depending on the technological parameters of detonation spraying was considered. The structural-phase states and tribological properties of detonation coatings were investigated by the following methods: X-ray phase analysis (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX-mapping), profilometry, and the test for wear-resistance according to the “ball-disk” scheme. It is shown that the phase composition of coatings may significantly change relative to the initial titanium powder during the detonation spraying due to the interaction of particles of powders with components of the gas atmosphere. Varying the spraying parameters may control the chemical reaction and provide conditions for the synthesis of the desired phases in the coatings (titanium oxide TiO2 and Ti2O3).

Flow-field characteristics and ventilation performance of the high-temperature buoyant jet controlled by spray-local exhaust ventilation

High-temperature buoyant jets are common pollutants in hot-rolling plants. Owing to the constraints of the process equipment, local exhaust hoods cannot be set near the buoyant jet source, resulting in low ventilation efficiency and high energy consumption. To efficiently control the high-temperature buoyant jet, spray-local exhaust ventilation (SLEV) is used in this study. The aspects discussed the flow-field characteristics, ventilation performance and recommended optimization parameter order for initial spray droplet diameter, spray angle, and exhaust velocity. The results showed that when the initial droplet diameter was 50 μm ≤ D < 100 μm, the spray gained significant entrainment and cooling effect on the buoyant jet, and when it increased to 150 μm, the spray gained almost no effect. Besides, when the spray angle was 20°<α ≤ 80°, the control ability of the spray on buoyant jet was enhanced; when α ≤ 20°, it was difficult to control buoyant jet owing to the small coverage of the droplets. In addition, the spray helps the escaped buoyant jet to be captured by the exhaust hood. The capture efficiency of the SLEV was higher than that of the local exhaust ventilation (LEV) at the same exhaust velocity. Finally, the exhaust hood and spray parameters must be matched for efficient buoyant jet control since they are interactive. The interaction between the exhaust velocity and initial spray droplet diameter can exert a greater impact on the capture efficiency than the interaction between the exhaust velocity and spray angle. The research results provide guidance for the application of SLEV and reduce ventilation energy consumption.

Metal Knitting: A New Strategy for Cold Gas Spray Additive Manufacturing.

Cold Spray Additive Manufacturing (CSAM) is an emergent technique to produce parts by the additive method, and, like other technologies, it has pros and cons. Some advantages are using oxygen-sensitive materials to make parts, such as Ti alloys, with fast production due to the high deposition rate, and lower harmful residual stress levels. However, the limitation in the range of the parts’ geometries is a huge CSAM con. This work presents a new conceptual strategy for CSAM spraying. The controlled manipulation of the robot arm combined with the proper spraying parameters aims to optimize the deposition efficiency and the adhesion of particles on the part sidewalls, resulting in geometries from thin straight walls, less than 5 mm thick, up to large bulks. This new strategy, Metal Knitting, is presented regarding its fundamentals and by comparing the parts’ geometries produced by Metal Knitting with the traditional strategy. The Metal Knitting described here made parts with vertical sidewalls, in contrast to the 40 degrees of inclination obtained by the traditional strategy. Their mechanical properties, microstructures, hardness, and porosity are also compared for Cu, Ti, Ti6Al4V, 316L stainless steel, and Al.