Thermal Monitoring and Control by Infrared Camera in the Manufacture of Parts With Laser Metal Deposition

Abstract

Techniques included in Additive Manufacturing (FA), especially Laser Metal Deposition (LMD), are subject to variable conditions during the manufacturing process. To achieve the required homogeneity in the manufacture of 3D components layer by layer, these instabilities must be compensated by adapting the process parameters. In this work, it is proposed to use an infrared (IR) thermal camera to monitor the evolution and thermal distribution of the surface of the parts produced, throughout the LMD deposition process. On the one hand, the influence of the temperature of the component on the resulting thickness is demonstrated. On the other hand, a control system is developed and implemented based on the adaptation of waiting times in order to maintain constant thermal conditions of the surface at the time prior to the deposition of each bead. The proposed control system is validated through LMD experimentation, demonstrating an increase in geometric homogeneity and the optimization of the time required for manufacture. This study is part of a wider development on LMD monitoring and control systems and its final objective is to increase the production capacities of this technology. Keywords: Additive Manufacturing, Laser Metal Deposition, infrared camera, thermal monitoring, thermal control, interlayer wait time.

Design and Development of a Multisensory Real-Time Monitoring Platform for Ultrafast Laser Engraving Process

“…Using an infrared thermal camera, the characteristics of the molten pool can be determined, and the temperature of the deposited surface can be measured and observed. IR cameras provided acceptable results for thermal monitoring and control of laser welding and laser additive manufacturing [20], [33], [34], [35]. However, in this study, the eligibility of IR camera to monitor the laser scribing process in real-time was evaluated.…”

“…Different types of cameras, photodiodes, pyrometers, and spectrometers are examples of optical sensors that can be used for monitoring purpose [15], [17], [18], [19]. It should be noted that thermal methods can be included in the group of optical methods [16], [20]. In this paper, infrared cameras and pyrometers have been classified in the category of optical sensors.…”

A Review on Wire-Laser Directed Energy Deposition: Parameter Control, Process Stability, and Future Research Paths

“…Various types of cameras, such as CCD (charge-coupled device), IR cameras, and CMOS (complementary metal oxide semiconductor), have been employed in research. Utilizing these monitoring systems allows for in-process monitoring; however, the brightness of the deposition area makes it difficult for the camera to accurately monitor the process [208,215,216]. A novel and promising approach is using optical coherence tomography (OCT) for real-time height measurements [217][218][219].…”

Investigation on the Cause-Effect Relationships between the Process Parameters and the Resulting Geometric Properties for Wire-Based Coaxial Laser Metal Deposition

“…Since heat accumulation is influenced by the height and the volume of the parts [42], the thermal conditions also changed for the different speed ratios. Higher speed ratios led to more material deposition and more heat accumulation, resulting in a progressively thicker wall [48]. The contour shapes of the cross-sections of the parts are shown in the Appendix A.…”