Review of the Formation Mechanisms and Control Methods of Geometrical Defects in Laser Deposition Manufacturing

Laser deposition manufacturing (LDM) is a revolutionary integrated manufacturing technology that expands numerous possibilities for producing large-scale parts in the aerospace and other industries. However, geometrical defects can severely affect the forming accuracy of parts and restrict the progress of LDM technology to large-scale components. This study summarizes the main types of geometrical defects and classifies them into four categories: flatness defects, melting collapse, distortion, cracking, and delamination. To overcome this challenge, one approach that has received considerable attention is process monitoring accompanied by mitigation strategies to improve the forming accuracy and repeatability. This study outlines the current understanding of the formation mechanism of common geometrical defects and discusses techniques to monitor the process and mitigate defects. Further, it discusses approaches for monitoring and controlling the LDM process while emphasizing the monitored melt pool, surface topography, temperature, and distortion. Next, the study focuses on procedures, including optimizing process parameters, thermal control methods, prediction, and compensation, to mitigate geometrical defects. Finally, the aim of the study is to provide a reference for researchers in this field. However, many future research hotpots for LDM precision control that require further investigation are still present.