Influences of process conditions on stability of sensor controlled robot-based laser metal deposition

Abstract

Robot-guided Laser Metal Deposition (LMD) process offers an efficient and resource-friendly production of big complex metals parts. In order to produce high-quality parts with minimum post-processing time, a highly stable process is required. The LMD process is characterized by numerous influencing physical parameters that lead to melt-pool instability, which results in shape irregularities in the component, followed by longer post-processing time. For process stability, control systems are necessary, which react to the occurring process and part deviations. The harsh environmental and process conditions impose high mechanical and thermal stresses on the sensors, which impact the accuracy of the system. In this paper, the factors influencing the accuracy of the sensors have been presented. The usability and stability of geometry control strategies with sensors have been evaluated against strategies without sensors. Additionally, the sensor system requirements for irregularity detection have been reported along with the guidelines developed for the implementation of a robust sensor control system for robot-based LMD processes.