Generating processing maps of metallic alloys manufactured by laser powder bed fusion technology

The growing trend of additive manufacturing processes aks for a parallel adjustment of already available models applied to industrial solidification processes. User friendly modeling codes can be a adopted as a valid aid in optimizing processes parameters ranges in the case of extending already existing modelling technologies to already developed or to new alloys. A modelling approach is here reported able to simulate the generation of single tracks scanned over the powder bed during a selective laser melting process. Track geometry is considered as function of: alloy thermo-physical properties, laser speed and power, powder bed thickness. The adopted approach is based on a simplified representation of the physical aspects. Main simplifying items concern: the laser energy input, modelling the formation of the pool cavity, modelling the powder bed thermo-physical properties. In the model, the effective laser absorptivity increase, with rising the specific energy is accounted at the onset of vaporization, to attain the real trend of pool volume increase, the subsequent pool cavity deepening and laser rays’ interceptions. Modeling the effective laser absorption variation has been validated using literature experimental data relating to laser welding tests performed on 316L disks. The model has been validated based on literature data providing track width and depth. The model is tailored on the following different alloys: Ti6Al4V, Inconel625, Al7050, 316L and pure copper.