Novel Line Heat Input Model for Process Simulation of Selective Laser Melting

Selective Laser Melting (SLM) is an additive manufacturing method that is gaining in popularity. Due to the nature of the SLM process, the component being built experiences rapid temperature cycling ranging between chamber temperature and the melting temperature of the material. This induces significant residual stresses in the component that can lead to deformation as well as failure of the support structure and/or the component. The vast majority of current simulation methodologies utilise either a heat source resembling that of the laser spot itself (point heat source) or a planar heat source that represents one or more layers being simultaneously deposited. The former approach is very computationally expensive due to the massive difference in time scale between the laser motion and the overall build time. The latter approach represents a severe averaging of the effects of the laser-powder interaction over a large volume with detrimental effects on the meso-scale accuracy. A novel line heat input model has been developed to fill this gap and provide meso-scale resolution on a component with significantly lower computational demand. Experimental work is being conducted to validate this model and initial results show very good correlation. The proposed model can offer insight into the SLM process, including but not limited to: understanding the effect of processing parameter on the temperature and residual stress, the buildability of different geometric features and the strength of various support structures.