Figure - available from: The International Journal of Advanced Manufacturing Technology
This content is subject to copyright. Terms and conditions apply.
Source publication
To avoid the effects of the overlap phenomenon among powder particles, the concept of an effective particle number was introduced, and multi-parameter analytical models for laser powder-fed additive manufacturing (LPF-AM) cladding geometric characteristics were established based on the laws of energy and mass conservation. Experimental research on...
Similar publications
Laser powder bed fusion (LPBF) enables the fabrication of metal parts characterized by high geometrical complexity, unique possibilities of customization and increasingly good mechanical properties. However, parts produced by LPBF are often characterized by poor geometrical and dimensional accuracy as well as by a number of internal defects, which...
Citations
... In the past, extensive computational work, both analytical and numerical, has been undertaken to understand gas-particle dynamics and laserparticle interactions. Analytical models [15][16][17][18][19][20][21] were formulated for the L-DED process to predict the temperature rise of powder particles resulting from in-flight laser-particle interactions and to estimate laser beam attenuation for various laser beam profiles, such as Top Hat and Gaussian. Numerical methods such as discrete phase modelling (DPM) Fig. 1. ...
... The phenomenological method is a type of analysis method based on multivariate mathematical statistics. It connects important controllable process parameters with required geometric features through mathematical relations [16][17][18]. It is mainly designed and developed by factor design, Taguchi design, central composite design (CCD), and response surface method (RSM) [19]. ...
The initial melting quality of a high-speed laser cladding layer has an important impact on its post-treatment and practical application. In this study, based on the repair of hydraulic support columns of coal mining machines, the influence of high-speed laser cladding process parameters on the quality of Fe-Cr-Ni alloy coatings was investigated to realize the accurate prediction of coating quality. The Taguchi orthogonal method was used to design the L25(56) test. The prediction models of the relationship between the cladding process and the coating quality were established using the Random Forest (RF) and AdaBoost (Adaptive Boosting, AB) algorithms, respectively. Then, the prediction accuracy of the two models was compared, and the process parameter features were screened for importance evaluation. The results show that the AB prediction model is more accurate than the RF prediction model and more sensitive to abnormal data. The importance evaluation based on the AdaBoost model shows that the scanning speed has a great influence on the height and surface roughness of the coating. On the other hand, the overlap rate is the most important factor in controlling the dilution ratio and near-surface grain size of high-speed laser melting coatings. In addition, the micro-hardness of the coating and the thermal effect of the substrate can be effectively enhanced by adjusting the laser power and scanning speed. Finally, it was verified that the AB prediction model could accurately estimate the quality indexes of the coating with a prediction error less than 6%. The results show that it is feasible to predict the quality of high-speed laser cladding with the AB algorithm. It provides a basis for the adjustment of process parameters in the subsequent quality control process of cladding.
... The powder particles within the powder bed were spherical, allowing for the development of a highly dense powder bed. The dilution rate between the substrate and the printed layer was ignored throughout the printing process [80]. Increasing the dilution rate causes the substrate to have a higher impact on the composition dilution of the deposited layer, resulting in poor performance [80]. ...
... The dilution rate between the substrate and the printed layer was ignored throughout the printing process [80]. Increasing the dilution rate causes the substrate to have a higher impact on the composition dilution of the deposited layer, resulting in poor performance [80]. Furthermore, the printing process frequently introduces cracks and other defects. ...
... Furthermore, the printing process frequently introduces cracks and other defects. The ideal dilution between the deposited layer and the substrate during the printing process is between 2 and 10%, and can be ignored for modeling purposes [80]. During modeling, temperaturedependent thermo-physical parameters were incorporated in the simulations, ensuring precise and accurate simulation results. ...
This study establishes a novel printability criterion for Inconel-718 parts by laser power bed fusion. For this purpose, the regions with D/t ≤ 1.15, L/W > 2.1, and W/D = 2.0 have been identified with lack-of-fusion, balling, and keyhole defects. Regimes within the processing maps related with defects have been regarded as a melt pool geometry function, derived using a FEM model with temperature-dependent thermophysical properties. The data was collected, via design of experiment technique, using validated simulation model. Following that, the acquired data was utilized to train and test a machine learning model based on a backpropagation artificial neural network (ANN). By linking melt pool dimensional ratios to defects, the validated ANN model was used to produce processing maps. The processing maps were validated using experimental analyses, which revealed a consistent correlation between experiments and simulations. The proposed processing maps can be utilized to quickly quantify the Inconel-718 parts generated by the LPBF.
... The dilution rate between the base plate and the printed layer is neglected throughout the printing process. The dilution rate equals the mixing area divided by the forming area 36 . Reduced bonding strength between the deposited layer and substrate occurs when the dilution rate is lowered due to reduced mixing area 36 . ...
... The dilution rate equals the mixing area divided by the forming area 36 . Reduced bonding strength between the deposited layer and substrate occurs when the dilution rate is lowered due to reduced mixing area 36 . The expected performance degrades as the dilution rate increases because the substrate has a greater impact on the deposited layer's composition dilution 36 . ...
... Reduced bonding strength between the deposited layer and substrate occurs when the dilution rate is lowered due to reduced mixing area 36 . The expected performance degrades as the dilution rate increases because the substrate has a greater impact on the deposited layer's composition dilution 36 . Furthermore, processing often results in cracks and other defects. ...
In this work, we propose a methodology to develop printability maps for the laser powder bed fusion of AISI 316L stainless steel. Regions in the process space associated with different defect types, including lack of fusion, balling, and keyhole formation, have been considered as a melt pool geometry function, determined using a finite element method model containing temperature-dependent thermophysical properties. Experiments were performed to validate the printability maps, showing a reliable correlation between experiments and simulations. The validated simulation model was then applied to collect the data by varying laser scanning speed, laser power, powder layer thickness, and powder bed preheating temperature. Following this, the collected data were used to train and test the adaptive neuro-fuzzy interference system (ANFIS)–based machine learning model. The validated ANFIS model was used to develop printability maps by correlating the melt pool characteristics to the defect types. The smart printability maps produced by the proposed methodology can be used to identify the processing window to attain defects-free components, thus attaining dense parts.
... More points were measured during the experiment and averaged for accuracy. Considering the forming quality is largely dependent on the melting speed in the double-pulse MIG aluminum alloy additive manufacturing process [25], a variable is introduced in a series of relevant experiments as shown in Table 2. The crystal and phase structural information of the samples was characterized using an X-ray diffractometer (XRD, D8ADVANCE) with Cu Ka radiation. ...
... The element distribution was scanned by electron probe micro analysis (EPMA, JXA-8530F). Considering the forming quality is largely dependent on the melting speed in the double-pulse MIG aluminum alloy additive manufacturing process [25], a variable is introduced in a series of relevant experiments as shown in Table 2. The crystal and phase structural information of the samples was characterized using an X-ray diffractometer (XRD, D8ADVANCE) with Cu Ka radiation. ...
Citation: Song, X.; Niu, J.; Huang, J.; Fan, D.; Yu, S.; Ma, Y.; Yu, X. The Effect of B 4 C Powder on Properties of the WAAM 2319 Al Alloy. Materials 2023, 16, 436. https://doi. Abstract: With ER2319 and B 4 C powder as feedstocks and additives, respectively, a wire arc additive manufacturing (WAAM) system based on double-pulse melting electrode inert gas shielded welding (DP-MIG) was used to fabricate single-pass multilayer 2319 aluminum alloy. The results showed that, compared with additive manufacturing component without B 4 C, the addition of which can effectively reduce the grain size (from 43 µm to 25 µm) of the tissue in the deposited layer area and improve its mechanical properties (from 231 MPa to 286 MPa). Meanwhile, the mechanical properties are better in the transverse than in the longitudinal direction. Moreover, the strengthening mechanism of B 4 C on the mechanical properties of aluminum alloy additive manufacturing mainly includes dispersion strengthening from fine and uniform B 4 C granular reinforcing phases and fine grain strengthening from the grain refinement of B 4 C. These findings shed light on the B 4 C induced grain refinement mechanism and improvement of WAAM 2319 Al alloy.
... L-DED has numerous advantages, such as a limited heat-affected zone, low dilute rate, low distortion, and high power efficiency [15]. With respect to these superiorities, the application of the L-DED technology includes the net-shape forming of complex 3D parts, attractive cladding, surface repair, and surface modification [16][17][18]. Therefore, L-DED technology is also known as laser cladding (LC), laser energy net shaping (LENS) or laser metal deposition (LMD) in some literature [19]. ...
... Phenomenological method, based on the multivariable mathematical statistical analysis, relates the most important controllable process parameters to geometrical features through a mathematical relation [29][30][31]. These statistical models are typically developed by means of factorial experiments and analysis of variance (ANOVA), central composite design (CCD) as well as response surface methodology (RSM) and Taguchi orthogonal design. ...
Stability of molten pool temperature directly affects the dimensional accuracy, metallurgical defects, solidification microstructure and mechanical properties of formed parts manufactured by laser metal deposition technology. Therefore, the optimization of the macroscopic morphology and microstructure of the formed parts through the stable control of the molten pool temperature has been intensively studied. In this study, three models, based on the back propagation neural network (BPNN), random forest (RF) algorithms and response surface methodology (RSM) approach, respectively, were used to establish prediction relationships between the deposition input parameters and processing status parameters, geometric morphology and mechanical property parameters. Then, the processing temperature and molten pool characteristics of thirty groups of 316L stainless steel single-track cladding layers were analyzed. The prediction results show that the average prediction error (APE) of the prediction of molten pool temperature, track width, track height and micro-hardness of the deposited layer based on BPNN model are 0.5%, 1.3%, 2.9% and 0.1%, respectively, which are better than the prediction results of RF and RSM models. Then, BPNN model was further used to predict the molten pool temperature and processing quality of the deposited layer under the combination of five new process parameters groups. Objective of this study was to lay the foundation for the subsequent design of the molten pool temperature control system to improve the morphology accuracy and mechanical properties of formed parts.
... If the dilution ratio is too large or too low, the cladding layer will easily delaminate and the expected performance of the cladding layer will decrease. An ideal dilution rate (2 ~ 10%) is the key to cladding layer forming and performance improvement [19]. The calculation method of dilution ratio in this paper is shown in Eq. (1) [20,21]. ...
... With the development of solidification process and the accumulation of heat, the temperature gradient decreases gradually, and the cladding region exhibits an increases tendency to dissipate heat to the outside [19,32]. The cooling rate of the outer surface of the cladding region is accelerated to form dendritic crystals and tends to shift to smaller crystal structure. ...
Experimental research on laser additive remanufacturing technology of heavy-duty sprocket was carried out. The influences of laser power, scanning speed, and powder feeding rate on cladding height, cladding area, melting area, and dilution rate were compared and analyzed. The prediction models of the combination of process parameters with the geometric characteristics of cladding layer and dilution were established. A multi-objective process parameter optimization model with the maximum cladding height and cladding area, the minimum melting area, and dilution rate as objective functions was established, and the model was optimized and solved based on MOPSO algorithm. The laser additive remanufacturing repairing experiment of damaged sprocket was carried out by using the optimal parameter combination, and the microstructure and mechanical properties of the repaired region were analyzed. The results show that the scanning speed and powder feeding rate are the main factors influencing the geometric characteristics and dilution of the cladding area, and the models have good prediction accuracy. The optimal process parameters (1150 W, 950 mm/min, 3.8 rad/min) obtained by MOPSO algorithm are adopted to repair the damaged sprocket. The repaired area without cracks and pores and the cladding layer show good metallurgical bonding with the substrate, and the microhardness is twice that of the substrate. The experimental results prove that the laser additive remanufacturing technology is feasible to repair the damaged heavy-duty sprocket and has a strong engineering application prospect.
... Upon melt pool solidification, near-net-shape parts are built layer-by-layer according to a pre-defined three-dimensional (3D) computer-aided design. The DED process is not limited solely to the deposition of 3D parts; it also has some attractive cladding [1,2] and repair [3] applications. The complex inherent process characteristics of the DED process, such as repeated heating-cooling thermal cycles, rapid solidification, and laser beam/delivered powder/melt pool interactions, have a direct effect on the properties of the deposited material. ...
... One way to tackle the challenge is to utilize advanced design of experiments (DOE) and statistical methodologies. Such DOE techniques were reported to be very efficient in: (1) the development of analytical predicting models in terms of input process parameters [18,23], (2) reducing the number of experiments [24], and (3) process optimization [17,25,26]. ...
Laser-directed energy deposition (DED) of high-quality structural Al-based alloys is challenging due to the inherent physical and thermal properties of the Al powder feedstock. Therefore, an in-depth understanding of the influence of the applied processing parameters on the characteristics of the deposited material paramount if one is to attain optimal performance. The objective of this study is to investigate the influence of the dominant processing parameters (laser power, scan speed, powder mass flow rate (PMFR), and hatch spacing) on the geometrical characteristics (track’s height and dilution) of Al5083 double tracks fabricated using Laser Engineered Net Shaping (LENS®). Central composite design (CCD) response surface methodology (RSM) was utilized to study the influence of the varied processing parameters and their interactions and to develop an empirical statistical prediction model for the studied responses. The results reveal that the applied PMFR has a strong influence on the deposited track’s height (positive) and dilution (negative). The laser power at the first-order factor shows a weak influence for both studied responses. However, the interaction between the laser power and the hatch spacing shows significant effects on the track’s height and dilution. The microstructure and microhardness of the as-deposited Al5083 double tracks are also discussed, as proxies to the anticipated performance of the deposited material.
... As the solidification moves towards the surface, the G/R ratio decreases. Due to the section effect and the change in the growth direction, the primary arm of the columnar crystals become much shorter than the crystals in the bottom region [33], form the dendritic crystals and have a tendency to transform into finer crystals. The twenty testing points extends from the cladding zone to the substrate. ...
In the laser Directed Energy Deposition (DED) manufacturing of parts, severe deformation caused by the uneven geometric characteristics of a multi-layer deposition fusion area occurs extremely easily due to the complexity and insufficient understanding of the process. The above results in a significant decline in the overall geometric quality of the parts. To study the influence of the laser DED process parameters on the geometric characteristics of multi-layer cladding, a response surface method was used to carry out an experimental study of the multi-layer cladding structures. Statistical prediction models of multi-layer cladding manufacturing were established among the laser power, scanning speed, powder feeding rate, lap ratio and cladding width, cladding zone area, fusion zone area, and flatness ratio. The accuracy, adaptability and relevance of the models were verified. The influence of each process parameter on the geometric characteristics of the multi-layer cladding structure was analysed, and the laser DED process parameters were optimized. Experimental results show that the surface forming quality of specimens processed with optimized process parameters is good. Relative errors between the experimental and predicted values of the geometric characteristics of specimens are less than 9%; thus, the prediction models can suitably predict and control the geometric characteristics of a multi-layer cladding structure. The proposed optimization of process parameters can significantly improve the geometric quality of parts and has substantial value in engineering applications.
