Modeling the effects of coordinated multi-beam additive manufacturing

Abstract

In additive manufacturing (AM), it is necessary to know the influence of processing parameters in order to have better control over the microstructure and mechanical performance of the part. Laser powder bed fusion (LPBF) AM is beneficial for many reasons; however, it is limited by the thermal solidification conditions achievable in the available processing parameter ranges for single-beam processing methods. Therefore, this work investigates the effect of multiple, coordinated heat sources, which are used to strategically modify the melting and solidifying in the AM process. To model this, existing thermal models of the LPBF process have been modified to include the effects of multiple, coordinated laser beams. These computational models are used to calculate melt pool dimensions and thermal conditions (thermal gradient and cooling rate). Furthermore, the results of the simulations are used to determine the influence of the distance between the coordinated laser beams in different configurations. The multi-beam scanning strategies modeled in the present study are shown to alter both melt pool shape and size, and the thermal conditions at the onset of solidification. However, these variations are not shown to result in alterations in the grain morphology of Ti-6Al-4V components. This predictive method used in this research provides insight into the effects of using multiple coordinated beams in LPBF, which is a necessary step in increasing the capabilities of the AM process.