SGER: Synergistic and Inherently Stable Laser/Plasma-Jet Welding Processes: Proof of Concept

该SGER赠款旨在开发一种试验系统，通过将光纤激光器和等离子射流相结合来实现协同和稳定的深熔焊接。该试验系统的成功在很大程度上依赖于实时等离子体传感器以及光纤激光器和等离子体射流的集成。为了开发这种实时等离子体传感器，高速摄影系统将与高性能计算系统集成，以高达200，000 fps的帧速率进行图像处理。该高速摄影系统允许PI观察小孔和等离子体喷射的振荡，以验证和改进新的等离子体传感器阵列的设计。观察还允许验证目前正在开发的激光/等离子体射流过程的严格数学建模。关键技术在于具有中等功率的激光束和具有特殊喷嘴设计的等离子体炬的协同能量沉积。激光，其高得多的功率密度，将创建小孔，而从等离子体炬精细聚焦等离子体射流将提供额外的能量沉积。通过对等离子体射流和激光诱导等离子体的主动调节，可以稳定小孔。闭环深熔激光焊接工艺的成功开发将是这一领域的突破。申请SGER授权将允许PI证明协同能量沉积概念以及工艺的内在稳定性，从而为闭环焊接系统奠定基础。由于缺乏实时反馈传感器，这种闭环系统还没有尝试过。该技术将使激光焊接在更大范围的工业中经济可行。美国工业需要这种先进技术来提高竞争力，以扭转许多大公司将工作外包的趋势。此外，美国的激光加工车间（超过10，000家）将看到他们的服务能力因这种技术的可用性而显着提高。在计算上，该项目使用了新的数值策略组合。这项工作是在一个跨学科的小组环境中进行的，通过课程和项目将研究与本科生和研究生结合起来。

This SGER grant aims at developing a pilot system to achieve synergistic and stable deep penetration welding by combining a fiber laser and a plasma jet. The success of this pilot system heavily relies on a real-time plasma sensor and the integration of the fiber laser and the plasma jet. To develop this real-time plasma sensor, a high speed photography system will be integrated with a high performance computing system for image processing at a frame rate up to 200,000 fps. This high speed photography system allows the PIs to observe the oscillation of keyhole and plasma ejection in order to validate and refine the design of the new plasma sensor array. The observation also allows the validation of rigorous mathematical modeling of the laser/plasma-jet process currently under development. The key technology resides in synergistic energy deposition of a laser beam with moderate power and a plasma torch with a special nozzle design. The laser, with its much higher power density, will create the keyhole while a finely focused plasma jet from the plasma torch will provide additional energy deposition. The keyhole will be stabilized through active regulation of the plasma jet and the laser-induced plasma. The successful development of closed-loop deep penetration laser welding processes will be a breakthrough in this area. The request SGER grant will allow the PIs to prove the synergistic energy deposition concept as well as the inherent stability of the process, thus, establishing the foundation for a closed-loop welding system. Such a closed-loop system has not been attempted because the lack of real-time feedback sensors.The technology will render laser welding economically viable for a much larger range of industries. The US industry is in need of this kind of advanced technology to boost competitiveness in order to turn back the tide of off-shoring jobs by many major corporations. Further, US laser job shops (over 10,000) will see their service capability significantly increased by the availability of such a technology. Computationally, the project uses novel combination of numerical strategies. The work is being performed in an interdisciplinary group environment that integrates research with undergraduate and graduate students through both courses and projects.