Abstract
Multi-laser selective laser melting (ML-SLM) is an emerging additive manufacturing technology, and it can rapidly fabricate large and complex parts. The published research on this subject is useful in optimizing the ML-SLM process. However, further research is necessary to understand the characteristics of parts formed using two or more lasers. In this study, the dual-laser (misaligned) and the single-laser Ti6Al4V SLM samples provided by DMG Mori were analyzed and compared with the annealed Ti6Al4V round bar samples for defect characteristics, porosity, and mechanical properties. It was demonstrated that the largest defect for the dual-laser (misaligned) samples is ~60 times larger than the largest defect for the single-laser samples. The average porosity of about 2.5% for dual-laser (misaligned) samples resulted in a loss of the tensile strength, the modulus of elasticity, and ductility by 81%, 42%, and 88% respectively in comparison to the single-laser samples. The hardness values for the single-laser samples are 63% higher than dual-laser (misaligned) samples. It was concluded that processing defects during manufacturing can have a hugely detrimental effect on the microstructure and mechanical properties of the finished parts.