Laser additive manufacturing has been regarded as a typical green manufacturing process. This paper presents a novel numerical approach termed time step fusion (TSF) along with the finite volume method (FVM), for fast computing the temperature field in a predominant laser additive manufacturing process, namely, selective laser melting. The solution acceleration strategy using TSF is that the entire computational domain is partitioned into multiple subdomains, and in the subdomain distant from the laser source and with the milder thermal gradients, larger time steps are employed. A thin wall is simulated to verify the proposed TSF method and evaluate its effectiveness and efficiency. The results are compared with those of the standard FVM model without TSF. It shows that they are in good agreement in terms of the spatiotemporal thermal profiles. The mean absolute error for the case studies with TSF is below 1 K except for a few spikes of the discrepancy reaching up to 15 K in the molten pool. Meanwhile, up to 28% acceleration in computational speed is obtained with TSF-FVM compared with regular FVM, and 93% time saving is achieved compared with a benchmark FEM model with a commercial solver. An extended case study is also presented to further verify the applicability of the proposed approach for complex geometries. The factors that contribute to the speed are analyzed, and the strategies for potential further improvement are also discussed.

激光增材制造已被视为典型的绿色制造工艺。本文提出了一种称为时步融合（TSF）和有限体积法（FVM）的新型数值方法，用于快速计算主要的激光增材制造过程中的温度场，即选择性激光熔化。使用TSF的解决方案加速策略是将整个计算域划分为多个子域，并且在远离激光源且具有较缓的热梯度的子域中，将使用较大的时间步长。模拟薄壁以验证所提出的TSF方法并评估其有效性和效率。将结果与没有TSF的标准FVM模型的结果进行比较。这表明它们在时空热剖面方面非常吻合。使用TSF进行的案例研究的平均绝对误差低于1 K，除了在熔池中达到15 K的一些差异峰值。同时，与常规FVM相比，TSF-FVM可获得高达28％的计算速度加速，与带有商用求解器的基准FEM模型相比，可以节省93％的时间。还提出了扩展的案例研究，以进一步验证所提出的方法在复杂几何形状中的适用性。分析了影响速度的因素，并讨论了可能进一步改善的策略。与常规FVM相比，TSF-FVM可获得高达28％的计算速度加速，与带有商用求解器的基准FEM模型相比，可以节省93％的时间。还提出了扩展的案例研究，以进一步验证所提出的方法在复杂几何形状中的适用性。分析了影响速度的因素，并讨论了可能进一步改善的策略。与常规FVM相比，TSF-FVM可将计算速度提高多达28％，与带有商用求解器的基准FEM模型相比，可节省93％的时间。还提出了扩展的案例研究，以进一步验证所提出的方法在复杂几何形状中的适用性。分析了影响速度的因素，并讨论了可能进一步改善的策略。