Visual Sensing and Image Processing for Error Detection in Laser Metal Wire Deposition

Laser metal deposition with wire (LMD-w) involves feeding metal wire through a nozzle and melting the wire with a high-power laser. With efficient process control, i.e. sensing, processing, and feedback correction of errors, the technology has the potential to change the course of manufacturing. However, the limitation most often encountered in LMD is the difficulty in controlling the process. Monitoring and control of metal additive manufacturing processes has been mostly researched on powder-based systems and has not been extensively investigated on metal wire feed systems. This work proposes a method for detecting discontinuities in a deposited layer in the LMD-w process via optical inspection and processing of images obtained from a high-resolution camera. The aim is to develop an effective sensing module that automatically detects irregularities in each layer before proceeding to subsequent layers, which will reduce part porosity and improve inter-layer bond integrity.