Melt Pool Characterization for Selective Laser Melting of Ti-6Al-4V Pre-alloyed Powder

Parameter optimization for metal powders in Selective Laser Melting (SLM) is usually carried out by experimental investigations of the influence of significant parameters (such as laser power, scan speed, hatch spacing, layer thickness, scan pattern, etc.) on microstructure and/or mechanical properties. This type of experimental optimization is extremely time- and cost-consuming. In order to accelerate the optimization process, a study was undertaken to develop a method for rapid optimization of parameters based on melt pool characterizations. These characterizations began with investigations of SLM single bead experiments. Pre-alloyed Ti-6Al-4V powder was used for single bead fabrication with multiple laser power and scan speed combinations. Surface morphology and dimensions of single beads were characterized. Geometrical features of melt pools were measured after polishing and etching of the cross section of each single bead. It was found that melt pool characteristics provide significant information that is helpful for process parameters selection. These experiments are being extended to characterize test pads with multiple layers.