Please give a lot of attention and participation from the members of the Mechanical Engineering department.

▣ 주   제: Process Monitoring and Control in Metal Additive Manufacturing

▣ 연   사: Jihoon Jeong 교수

▣ 소   속: Texas A&M 

▣ 일   시: 2024. 6. 27.(Thu) 11:00

▣ 장   소: 제4공학관 D603호

▣ 초   청: 현재상 교수

▣ 초   록

In-situ monitoring is critical for fundamental understanding and developing control methods, advanced materials, and tool path planning strategies in metal additive manufacturing (AM). In-situ monitoring techniques have mainly focused on melt pool monitoring and typically involve off-axis or coaxially mounted cameras (e.g. IR, CCD, and CMOS), which generate 2-D data. While these techniques capture critical deposition information, they do not capture other important phenomena, such as the unique coupling between the laser and melt pool, which ultimately limits the design and generality of open-loop and closed-loop process control. We establish in-situ, parallel signals at fast rates of 100 kHz by monitoring multiple process phenomena at the same time through different wavelength bands and thermal calibration. Ultimately, a relationship between each change in process parameter and the relative absorption of the laser was established. In-situ monitoring of the laser coupling phenomenon not only provides insight into material processing conditions but will also enable more complex control in metal AM processes. By implementing photodiodes as a functioning two-color pyrometer, we established 415 Hz signals that were used to control melt pool temperature throughout a build by modulating laser power. In addition, a simulation-guided feedforward-feedback control framework will be discussed to effectively manipulate the melt pool temperature in metal AM processes.