In-Process Detection of Defects on Parts Produced by Laser Metal Deposition Using Off-Axis Optical Monitoring

Abstract

Laser Metal Deposition (LMD) is emerging among metal Additive Manufacturing technologies due to its wide range of applications. This technique represents an evolution of laser cladding, currently used for fabricating and repairing complex metal components, promoting manufacturing sustainability. One of the main drawbacks hindering the widespread use of these technology is the complexity of implementing monitoring equipment on industrial LMD systems with limited modification setups. Therefore, it is essential to develop appropriate off-axis systems that allow effective monitoring of the deposition process. The present work proposes a prototype off-axis monitoring system consisting of a pair of specially set cameras capable of analyzing the evolution of the melt pool and discerning fundamental information on geometry, size and brightness intensity. By correlating this information with the process outcome, it could be possible to forecast the most frequent defects related to the deposition process. Experimental tests have been carried out, in which powder flow and laser alterations were specifically induced. The prototype system enabled the characterization of each type of process variation and the determination of specific indicators, serving as the basis for achieving a zero-waste sustainable manufacturing process.