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Optimization of Surface Roughness and Power Consumption in laser-assisted machining of Inconel 718 by Taguchi based Response Surface Methodology
摘要： Inconel 718 a difficult-to-machine material is used in critical aero engines components. Surface roughness (product quality) and power consumption (energy efficiency) are two important benchmark factors for manufacturing industry as it deserves to determine the optimal design points in laser assisted machining (LAM) for sustainability performance of the machining process. Moreover, the optimization of laser beam angle and laser power along with technological parameters (cutting speed, feed rate) is not reported in the literature during laser-assisted machining (LAM) of Inconel 718. In this context, it is worthy to investigate the effects of these parameters on these two quality characteristics during the LAM of this fantastic material. Laser aided machinability experiments are carried out with coated carbide insert at three different cutting speeds (60, 105 and 150 m/min), three different feed rates (0.05, 0.0875 and 0.125 mm/rev), three laser power (1250, 1500 and 1750 W) and three laser beam angle (60, 70, 80 deg) under lased-aided dry cutting conditions. The percent contribution of the main effects of the cutting parameters to the quality parameters is determined using analysis of variance (ANOVA), and predictive linear equations are developed for the estimation of all the quality characteristics. Thereafter, optimal cutting parameters are obtained.
关键词： power consumption,surface roughness,laser parameters,analysis of variance
更新于2025-09-16 10:30:52
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Estimation of Optimal Laser Parameters On Inconel 718 By Taguchi Methodology
摘要： Inconel 718 is a representative of high temperature alloy which poses substantial difficulties in machining processes. High strength, high cutting temperature and a subsequent work hardening during machining process adversely affect the cutting force, surface integrity, tool life and chip breakability. The above difficulties have been disproving by employing the Laser Assisted Machining (LAM). LAM is a hybrid technique and used to machining the work-piece with conventional tool after softening it with laser emitted heat. An attempt has been made in the present study for an experimental investigation on the machining attributes of 718 Inconel super alloy during laser assisted machining using uncoated carbide insert. Experimental plan is designed based on Taguchi’s L18 mixed orthogonal array of design of experiment. Three response values such as cutting force, surface roughness and tool wear are measured and their effects are studied. The variability due to the machining parameters are dispensed using variance test. Predictive regression equations are developed for the estimation of all the quality characteristics. Also the Pearson correlation coefficient analysis is calculated to analyze the correlation between the input parameters and quality characteristics. Results showed a strong correlation between the feed rate and the cutting force and surface roughness followed by cutting speed. The results obtained from experiments are analyzed to predict the optimal machining conditions using desirability approach. At the optimal laser parameters, the tool life, when laser beam is used, is improved by 9% compared to conventional machining.
关键词： cutting forces,Taguchi method,surface roughness,tool wear,laser parameters
更新于2025-09-16 10:30:52
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Evaluation of internal defects generated in machine milled carbon fiber reinforced plastic using X-ray computed tomography
摘要： In this study, X-ray computed tomography (X-ray CT) was used to investigate internal defects generated on machine milled carbon fiber reinforced plastics (CFRP). Internal defects such as cracks, fractures, and deformation of the carbon fibers, which are invisible from the surface, were observed using the X-ray CT method. Defects were generated based on the machining method and direction of the fibers. A large number of defects were generated when using the conventional cut method along 45°, 90°, and the climb cut method along 90°. Few internal defects were observed when using the climb cut method along 45°; however, the machined surface was very rough. The mechanism for these phenomena was investigated by studying surface observations and cutting force, in addition to X-ray CT imaging. These results indicate that X-ray CT is a powerful tool for visualizing internal defects in CFRP, which differ significantly based on the direction of the fiber and machining method used.
关键词： Carbon fiber reinforced plastics,Surface roughness,Milling,Internal defect,X-ray computed tomography
更新于2025-09-16 10:30:52
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Study on laser-stricken damage to alumina ceramic layer of different surface roughness
摘要： This study examines the laser-stricken damage to different alumina ceramic surfaces of different roughness through multi-physical field coupling simulations and laser-striking experiments. The surfaces of different morphologies can be described by waves of different frequencies and amplitudes, and the waves which are discretized can be described by rectangular microstructures of different heights. In this paper, we found that the reaction of roughness surfaces to gauss lasers stricken on them could be simulated by the reaction of rectangular microstructures of different heights to laser strike. The simulation was carried out through the multi-physical field coupling method. The distribution of temperature and stress on rectangular microstructure were examined after being treated by high energy laser. It was found that overhigh temperature and stress were the main causes of laser-stricken damage, but there existed a critical rectangular column height value. The microstructure became increasingly prone to damage and fall-off with the increase of the rectangular column’s height, but it became decreasingly prone to damage after the rectangular column reached the critical value. In the experiments, seven roughness zones of alumina ceramic layer were chosen as sample surfaces for laser-striking experiment. The results showed that there was a critical roughness value at a fixed laser energy density. As a result, the amount of particles falling off the surfaces caused by laser strike was rising when the roughness was increasing. However, the amount of particles falling off the surfaces was decreasing after roughness reached the critical value. The critical rectangular column height value in the simulation corresponded to the critical roughness value in the experiment. Therefore, an appropriate selection of roughness is an important factor for obtaining high laser-stricken damage threshold.
关键词： simulation and experiment,surface roughness,rectangular microstructure,laser-stricken damage,alumina ceramic layer
更新于2025-09-16 10:30:52
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Finite Element Analysis of Surface Roughness Generated by Multiple Laser Shock Peening
摘要： Laser shock peening (LSP) is a novel surface processing technique for improving the fatigue properties of metal parts, and surface roughness is a critical parameter when fatigue strength resistance is concerned. In this paper, a three-dimensional (3D) finite element model was developed in order to assess the surface roughness evolution induced by multiple LSP. A modified finite element analysis (FEA) method was used to compute the vertical displacements profiles, and discrete data obtained from the numerical simulations were subsequently input to the proposed discretized formula to calculate the surface roughness Ra. The results obtained from the numerical simulations are in good agreement with the experiment data from open literatures, which validates the proposed approach. After the validation of the numerical model, a parametric study was conducted in order to predict the effects of overlap rates, number of impacts, and pulse energy on surface roughness Ra.
关键词： laser shock peening,surface roughness Ra,numerical simulation
更新于2025-09-16 10:30:52
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New Method for Evaluating Surface Roughness Parameters Acquired by Laser Scanning
摘要： Quality evaluation of a material’s surface is performed through roughness analysis of surface samples. Several techniques have been presented to achieve this goal, including geometrical analysis and surface roughness analysis. Geometric analysis allows a visual and subjective evaluation of roughness (a qualitative assessment), whereas computation of the roughness parameters is a quantitative assessment and allows a standardized analysis of the surfaces. In civil engineering, the process is performed with mechanical profilometer equipment (2D) without adequate accuracy and laser profilometer (3D) with no consensus on how to interpret the result quantitatively. This work proposes a new method to evaluate surface roughness, starting from the generation of a visual surface roughness signature, which is calculated through the roughness parameters computed in hierarchically organized regions. The evaluation tools presented in this new method provide a local and more accurate evaluation of the computed coefficients. In the tests performed it was possible to quantitatively analyze roughness differences between ceramic blocks and to find that a quantitative microscale analysis allows to identify the largest variation of roughness parameters Raavg, Rasdv, Ramin and Ramax between samples, which benefit the evaluation and comparison of the sampled surfaces.
关键词： roughness parameters,laser scanning,hierarchical analysis,civil engineering,surface roughness
更新于2025-09-12 10:27:22
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Systematic approach for determining optimal processing parameters to produce parts with high density in selective laser melting process
摘要： Relying on trial-and-error methods to determine the optimal processing parameters which maximize the density of parts produced using selective laser melting (SLM) technique is costly and time consuming. With a given SLM machine characteristics (e.g., laser power, scanning speed, laser spot size, and laser type), powder material, and powder size distribution, the present study proposes a more systematic strategy to reduce the time and cost in finding optimal parameters for producing high-density components. In the proposed approach, a circle packing design algorithm is employed to identify 48 representative combinations of the laser scanning speed and laser power for a commercial Nd:YAG SLM system. For each parameter combination, finite element heat transfer simulations are performed to calculate the melt pool dimensions and peak temperature for 316L stainless steel powder deposited on a 316L substrate. The simulated results are then used to train the artificial neural networks (ANNs). The trained ANNs are used to predict the melt pool dimensions and peak temperature for 3600 combinations of the laser power and laser speed in the design space. The resulting processing maps are then inspected to determine the particular parameter combinations which produce stable single scan tracks with good adhesion to the substrate and a peak temperature lower than the evaporation point of the SS 316L powder bed. Finally, the surface roughness measurements are employed to confirm the parameter settings which maximize the SLM component density. The experimental results show that the proposed approach results in a maximum component density of 99.97 %, an average component density of 99.89%, and a maximum standard deviation of 0.03%.
关键词： Additive manufacturing,Selective laser melting,Surface roughness,Artificial neural network,Surrogate model
更新于2025-09-12 10:27:22
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Improvement of CsPbBr3 photodetector performance by tuning the morphology with PMMA additive
摘要： The optoelectrical properties of semiconductor devices are strongly related to the film morphology. Here, we found that, for CsPbBr3 thin films prepared by spray coating, the addition of polymethyl methacrylate (PMMA) can completely eliminate voids and greatly reduce the surface roughness of the as-deposited films. As a consequence, the optoelectronic properties of the photodetectors fabricated as a simple vertical structure of Au/CsPbBr3(PMMA)/ITO can be improved. With the addition of PMMA, the dark current of the photodetector is reduced at least four times, and the photodetector exhibits a favourable optical response. With the illumination ranging from 400 to 510 nm, the calculated responsivity varies from 3.70 to 5.20 A/W. A good response speed with a rise time of 6.6 ms and a decay time of 11.3 ms can be achieved. Moreover, unlike the inorganic-organic hybrid perovskite detectors, this inorganic perovskite photodetector without encapsulation shows a favourable stability with a decay of 20% after 40 days under ambient air at 20% humidity.
关键词： Photodetector,Spray coating,PMMA,Surface roughness,CsPbBr3
更新于2025-09-12 10:27:22
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Effect of repeated laser surface treatments on shear bond strength between zirconia and veneering ceramic
摘要： Statement of problem. Delamination failure may occur between ceramic frameworks and veneering ceramics, shortening the lifetime of ?xed dental prostheses in load-bearing areas. Purpose. The purpose of this in vitro study was to compare the effect of different repeating CO2 laser treatment methods and conventional approaches on the shear bond strength of zirconia frameworks and veneering ceramics. Material and methods. Zirconia disks (N=110) were prepared and divided into 5 groups: milling without surface treatment (group M), airborne-particle abrasion (group APA), single laser treatment (group LX1), 2 laser treatments (group LX2), and 3 laser treatments (group LX3). The specimens in the ?rst 2 groups were treated before the framework was coated using the spraying technique. Specimens in the remaining groups were coated with veneering ceramic using the spraying process, and then subjected to laser treatment. Surface roughness and topography, interface properties, phase transformation, shear bond strength, and fracture modes were investigated. Outcomes were analyzed using a pro?lometer, a scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS), X-ray diffractometry (XRD), a stereomicroscope, and a universal testing machine for mechanical testing. Results. The XRD showed that phase transformation from tetragonal to monoclinic occurred after airborne-particle abrasion. This phenomenon was not observed in laser-treated specimens. Groups LX2 and LX3 had the highest surface roughness values, 1.18 ±0.23 mm and 1.21 ±0.22 mm, among all groups, and group LX3 had the highest shear bond strength values for unaged and aged conditions, 32.08 ±2.45 MPa and 31.43 ±2.07 MPa. The mixed-fracture mode was the most common type of fracture observed. Conclusions. The results indicated that the shear bond strength between the zirconia framework and veneering ceramic was higher after laser surface treatments than after milling alone or after airborne-particle abrasion. Laser treatment methods, particularly LX2 and LX3, could be considered reliable approaches for zirconia surface treatment.
关键词： veneering ceramic,laser treatment,zirconia,shear bond strength,surface roughness
更新于2025-09-12 10:27:22
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Melt pool monitoring for laser beam melting of metals: inline-evaluation and remelting of surfaces
摘要： Laser Beam Melting of Metals (LBM-M) is an additive manufacturing technique that is applied successfully for the production of complex parts, small batch series and prototypes. In LBM metallic parts are generated layer by layer directly from sliced CAD data. For each layer a thin powder layer is deposited and subsequently irradiated by a focused laser beam which is guided by a galvanometer scanner. Due to variations in the powder stock, plain parameter sets and unresolved machine maturity problems, quality fluctuations are a major problem for a future series production. Surface roughness of parts during manufacturing is a quality issue. In this paper, we address it with a coaxial melt pool monitoring system and show a method for inline evaluation of surfaces by means of melt pool monitoring and the results of applied remelting strategies.
关键词： Laser Beam Melting,Additive Manufacturing,process stability,remelting,Selective Laser Melting,Melt pool Monitoring,Surface roughness,quality assurance
更新于2025-09-12 10:27:22