Compared with other additive manufacturing processes, the metal-based additive manufacturing (MAM) can build higher precision and higher density parts, and have unique advantages in the applications to automotive, medical, and aerospace industries. However, the quality defects of builds, such as dimensional accuracy, layer morphology, mechanical and metallurgical defects, have been hindering the wide applications of MAM technologies. These decrease the repeatability and consistency of build quality. In order to overcome these shortcomings and to produce high-quality parts, it is very important to carry out online monitoring and process control in the building process. A process monitoring system is demanded which can automatically optimize the process parameters to eliminate incipient defects, improve the process stability and the final build quality. In this paper, the current representative studies are selected from the literature, and the research progress of MAM process monitoring and control are surveyed. Taking the key components of the MAM monitoring system as the mainstream, this study investigates the MAM monitoring system, measurement and signal acquisition, signal and image processing, as well as machine learning methods for the process monitoring and quality classification. The advantages and disadvantages of their algorithmic implementations and applications are discussed and summarized. Finally, the prospects of MAM process monitoring researches are advised.

与其他增材制造工艺相比，基于金属的增材制造（MAM）可以制造更高精度和更高密度的零件，在汽车、医疗和航空航天等行业的应用中具有独特的优势。然而，构建的质量缺陷，如尺寸精度、层形貌、机械和冶金缺陷，一直阻碍着 MAM 技术的广泛应用。这些降低了构建质量的可重复性和一致性。为了克服这些缺点并生产出高质量的零件，在建造过程中进行在线监控和过程控制非常重要。需要一种可以自动优化工艺参数以消除初期缺陷的过程监控系统，提高工艺稳定性和最终构建质量。本文从文献中选取当前具有代表性的研究，对MAM过程监控的研究进展进行了综述。本研究以MAM监控系统的关键部件为主流，研究了MAM监控系统、测量和信号采集、信号和图像处理，以及过程监控和质量分类的机器学习方法。讨论和总结了它们的算法实现和应用的优缺点。最后对MAM过程监控研究的前景进行了展望。本研究以MAM监控系统的关键部件为主流，研究了MAM监控系统、测量和信号采集、信号和图像处理，以及过程监控和质量分类的机器学习方法。讨论和总结了它们的算法实现和应用的优缺点。最后对MAM过程监控研究的前景进行了展望。本研究以MAM监控系统的关键部件为主流，研究了MAM监控系统、测量和信号采集、信号和图像处理，以及过程监控和质量分类的机器学习方法。讨论和总结了它们的算法实现和应用的优缺点。最后对MAM过程监控研究的前景进行了展望。讨论和总结了它们的算法实现和应用的优缺点。最后对MAM过程监控研究的前景进行了展望。讨论和总结了它们的算法实现和应用的优缺点。最后对MAM过程监控研究的前景进行了展望。