Abstract Conventional laser-based powder bed fusion of metals (PBF-LB/M) currently faces technological challenges in scalability due to its low building rate and manufacturing throughput. One approach to address this issue is to parallelize multiple laser beams to increase processing flexibility. Recent research has studied, for instance, the improvements to mechanical properties of final products when using two or more laser beams in PBF-LB/M. However, some obstacles still need to be addressed involving the proximity of molten pools and their interaction mechanism. In particular, interactions between two close, parallel molten pools have not been fully understood yet. In this study, two lasers create two parallel-running molten pools with a small spatial offset in between. With different spatial offsets, experimental results reveal that besides the completely merged and completely separated regimes, there exists a new regime which yields periodic coalescence between the two molten pools. High-speed imaging shows two different mechanisms for the formation of such coalescence, what we denote as head-to-head and head-to-tail coalescence. By changing processing parameters including laser power and spatial offset, periodic structures with various wavelengths can be engineered using this dual-laser approach.

中文翻译：

---

使用双激光系统在激光粉末床聚变中产生周期性聚结

摘要 传统的基于激光的金属粉末床融合 (PBF-LB/M) 由于其低构建率和制造吞吐量，目前在可扩展性方面面临技术挑战。解决此问题的一种方法是并行化多个激光束以提高加工灵活性。例如，最近的研究已经研究了在 PBF-LB/M 中使用两个或多个激光束时最终产品机械性能的改进。然而，仍然需要解决一些障碍，涉及熔池的接近程度及其相互作用机制。特别是，尚未完全了解两个紧密平行的熔池之间的相互作用。在这项研究中，两个激光器创建了两个平行运行的熔池，其间具有很小的空间偏移。具有不同的空间偏移，实验结果表明，除了完全合并和完全分离的状态外，还存在一种新的状态，可以在两个熔池之间产生周期性聚结。高速成像显示了形成这种聚结的两种不同机制，我们将其称为头对头和头对尾聚结。通过改变包括激光功率和空间偏移在内的加工参数，可以使用这种双激光方法设计具有各种波长的周期性结构。