Process Development for a Robotized Laser Wire Additive Manufacturing

Additive manufacturing has attracted the attention of industries such as aerospace and automotive as well as the medical technology sectors in recent years. Among all metal-based additive techniques, laser metal wire deposition offers some advantages like shorter processing time, more efficient material usage, and a larger buildup envelop. It has been found that robotized laser/wire additive manufacturing (RLWAM) is a demanding process. A plethora of process parameters must be controlled compared to other laser-based metal deposition processes. The influence of main process parameters such as laser power, stepover increment, wire feed speed, travel speed and z-increment was investigated in this study to find the optimal values. Droplet formation, wire dripping, irregular deposition in the first layer, and deviation of the wire tip were also found to be the main obstacles throughout the process and practical solutions were proposed to deal with these issues. In this study, an 8-axis robot (6-axis arm robot with a 2-axis positioner) and a 4 kW fiber laser along with a wire feeder were integrated to print the different geometrical shapes in 3D. In order to verify the geometrical accuracy of the as-built part, the buildup was scanned using a portable 3D laser scanner. The 3D representation, the Standard Tessellation Language (STL) format obtained from the buildup, was compared with the original CAD model. The results show that RLWAM can be successfully applied in printing even complicated geometries.