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Recently developed concentric laser metal wire deposition (LMWD) heads allow metal addition processes which are independent of the deposition direction, thus enabling complex paths to be generated. The sensitivity of the process to height deviations has experimentally been observed to be greater with this type of head than with powder ones, therefore requiring more precise and local process control algorithms to be implemented. This work developed a methodology for measuring the part, layer by layer, using a 3D scanner based on structured laser light. Height corrections were applied to the mean and intra-layer height deviations by recalculating the deposition trajectories of the next layer to be deposited. Local height deviations were adjusted by varying the scanning speed, thus increasing the feed rate in the lower areas and decreasing it in the higher ones. Defects generated in the purpose, with height differences within the layer, were successfully corrected. A flat layer was re-established through the application of the control strategy. The internal integrity of the parts due to the scanning speed variation was analyzed, resulting in fully dense parts. The structured light measurement and height correction systems are found to be an affordable and time-efficient solution that can be integrated into an LMWD environment, thereby improving the process robustness.

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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.

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