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Materials Science in Additive Manufacturing                         Bead geometry prediction in laser-arc AM



            the layer-by-layer deposition and solidification of metal   Table 1. Overview of research on data modeling between
            feedstock, MAM creates new possibilities for designing   process parameters and layer geometries in metal additive
            and  producing  intricate  metallic  parts,  significantly   manufacturing
                                              2-4
            enhances manufacturing productivity, propels innovation   Process  Models  Inputs  Outputs    Ref.
            in product design and processing routes, and expedites the   LPBF  RF and   Laser power and   Layer height,   27
            overall evolution of industrial manufacturing.  Among         ANN    scanning velocity  width, and
                                                  5,6
            MAM technologies, powder bed fusion (PBF) and directed                            penetration
            energy deposition (DED) are the most widespread;  wire-                           depth
                                                     7
            feed DED, in particular, garners interest for its superior   Powder-laser   SVR  Laser power, travel  Layer height and  28
            deposition rates and  material efficiency.   Wire-feed   DED         speed, and powder  width
                                               8,9
            additive manufacturing utilizes lasers, electron beams, or           feed rate
            welding arcs as energy inputs. In comparison with laser-or   Wire-laser DED NB  Laser power, travel  Layer height and  29
            electron-beam-based AM, wire arc additive manufacturing              speed, and wire   width
                                                                                 feed rate
            (WAAM) offers significant benefits in capital expenditure
            and build rate.  The typical deposition rate for laser or   WAAM  ANFIS  Wire feed rate and  Surface   30
                        10
                                                                                 travel speed
                                                                                              roughness
            electron beam AM lies between 2 and 10 g/min, whereas
            WAAM attains 50 – 130  g/min; 11,12  its energy efficiency   WAAM  SVR  Wire feed rate and  Layer height and  31
                                                                                 travel speed
                                                                                              width
            of roughly 90% greatly surpasses the 2 – 5% achieved by   WAAM  XGBoost Current and travel  Layer height,   32
            laser-based  AM. 13,14   Thanks  to  their  favorable  welding       speed        width, and area
            characteristics, aluminum–copper (Al–Cu) alloys serve   Abbreviations: ANFIS: Adaptive neuro-fuzzy inference system;
            as ideal materials for WAAM fabrication. 15-17  The bead   ANN: Artificial neural network; DED: Directed energy deposition;
            geometry, which represents the basic fabrication unit   LPBF: Laser powder bed fusion; NB: Naïve Bayes; RF: Random
            in WAAM, exerts a direct influence on the dimensional   forest; SVR: Support vector regression; WAAM: Wire arc additive
            fidelity of the manufactured component. Inadequate bead   manufacturing; XGBoost: Extreme gradient boosting.
            quality requires additional finishing operations, thereby
                                                                                                            27
            increasing labor expenditure and leading to material   laser power and scan speed as predictors, Le-Hong et al.
            wastage.                                           developed  random-forest  and  artificial-neural-network
                                                               models to estimate layer geometry in laser PBF, reporting
              Recently, the laser-arc hybrid approach to additive   validation R  values exceeding 90%. With laser power,
                                                                         2
            manufacturing  has  come  to  the  forefront  of  scholarly   travel speed, and powder feed rate as variables, Zhu et al.
                                                                                                            28
            interest. By steering the arc, the laser decreases its electrical   employed support vector regression (SVR) to predict the
            resistance and field strength, which in turn improves arc   layer height and width of DED, reaching 93% accuracy.
            stability and boosts the build rate.  When the two energy   Deploying a naïve Bayes approach, Liu and Kuo  studied
                                       18
                                                                                                      29
            sources are coupled, inverse bremsstrahlung further   wire-laser DED; by inputting travel velocity, laser power,
            augments laser-energy uptake, and the laser improves melt-  and wire feed speed, they predicted bead dimensions,
            pool convection as well as the homogeneity of elemental   yielding R² values of 91% and 94%. Xia et al.  employed
                                                                                                    30
            distribution.  Even so, integrating laser and arc complicates   a genetic-algorithm-tuned adaptive neuro-fuzzy inference
                      19
            the multiphysics interactions, greatly raising the challenge   system model to estimate surface roughness from wire
            of forecasting weld-bead dimensions. Consequently, the   feed and welding speeds, achieving validation R  values
                                                                                                       2
            precise  prediction of  weld-bead  geometry  in laser-arc   exceeding 90%. Oh et al.  introduced an SVR model into
                                                                                   31
            hybrid additive manufacturing (LAHAM) emerges as a   the WAAM process, using key parameters such as welding
            pivotal problem that demands prompt resolution.    current and wire feed rate to accurately predict bead width
              As an essential subdivision of artificial intelligence   and height and to identify geometric non-uniformity
            (AI), machine learning (ML) identifies patterns through   defects that may arise under different operating conditions.
                                                                       32
            data analysis and leverages them for prediction and   Šket et al.  used an extreme gradient boosting (XGBoost)
            decision-making tasks.  During the past decade, ML has   regression model, with current and travel speed as the two
                              20
            found broad applications across numerous domains, such   process parameters, to predict the geometric morphology
            as medical diagnostics,  forecasting material properties,    of the weld bead.
                                                         22
                              21
            intelligent manufacturing,  self-driving vehicles,  natural   Despite these advances in predicting layer geometries of
                                                   24
                                 23
            language processing,  and object detection.  A synopsis of   MAM based on process parameters, reliable estimation of
                                              26
                            25
            research forecasting the links between process parameters   bead size in LAHAM still confronts significant challenges.
            and layer geometry in MAM is provided in Table 1. Using   The link between LAHAM processing parameters and
            Volume 4 Issue 3 (2025)                         2                         doi: 10.36922/MSAM025220036
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