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




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            Figure 7. Predicted values (A) and error performance (B) of each model in the width prediction task
            Abbreviations: ANN: Artificial neural network; ELM: Extreme learning machines; GPR: Gaussian process regression; SVR: Support vector regression

            Table 7. Evaluation metrics of each model in the width   its maximum relative error stood at 4.2%, ranking second
            prediction task                                    to SVR, confirming PSO-EP’s outstanding precision and
            Model          MAE          RMSE          R 2      robustness in the weld bead height prediction task.
            GPR            0.2006       0.2400       0.9302    3.2. Comparison of PSO-EP with other ensemble
            SVR            0.1741       0.2012       0.9510    methods
            ANN            0.1704       0.2519       0.9231    Figure  10 presents a comparison of four ensemble
            ELM            0.2021       0.2322       0.9347    forecasting  approaches:  the  averaging  method,
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            PSO-EP         0.1454       0.1890       0.9567    Stacking,  ELGA,  and the PSO-EP method introduced
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            Abbreviations: ANN: Artificial neural network; ELM: Extreme learning   herein. Results indicated that PSO-EP attained an R  of
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            machines; GPR: Gaussian process regression; MAE: Mean absolute   0.9492 in predicting weld bead height, surpassing the
            error; PSO-EP: Particle swarm optimization-based ensemble prediction
            model; R : Coefficient of determination; RMSE: Root mean squared   averaging method (0.9387) by 1.12%, stacking (0.9378) by
                  2
            error; SVR: Support vector regression.             1.22%, and ELGA (0.9206) by 3.11%. For weld bead width
                                                               prediction, PSO-EP achieved an R  of 0.9567, which is
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            fluctuation points, struggling to precisely represent height   2.07% higher than the averaging method (0.9373), 3.47%
            changes. Quantitative assessment showed that the PSO-EP   higher than stacking (0.9246), and 2.36% higher than
            achieved an R  of 0.9492 (Table 8), again leading all models,   ELGA (0.9346). These notable improvements stem from
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            with RMSE and MAE metrics below those of competitors;   the PSO algorithm’s effective global optimization ability.
            Volume 4 Issue 3 (2025)                         9                         doi: 10.36922/MSAM025220036
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