Modelling of the thermal condition on selective laser melting (SLM) of zirconia powders

Abstract

Selective Laser Melting (SLM) is an additive manufacturing technique capable of fabricating complex products layer by layer in a wide range of materials, particularly for metallic materials. As for ceramic materials such as Zirconia however, inconsistent part density continues to pose a challenge to the understanding of the relations between SLM process parameters and the aforementioned material. In this report, the thermal effect of SLM parameters on Zirconia are investigated numerically. A three dimensional transient thermal finite element model of the SLM process is presented. Temperature distribution simulation of a single-track laser melting with both Uniform and Gaussian laser beam profiles are conducted on a single-layered Zirconia powder bed model. The simulation results show that higher laser power and slower scanning speed yield a higher maximum temperature in the powder bed for both laser beam profiles. Gaussian laser beam, despite inducing higher laser energy due to its smaller laser

spot diameter, attained a lower maximum temperature in the powder bed as compared to Uniform laser beam at lower scanning speed. A 2K experiment conducted to further investigate the main effect of laser power and scanning scan on the maximum temperature of the powder bed reveals that the main effect of laser power is higher than the main effect of scanning speed. This finding is consistent for both laser profiles. The higher laser power induced a higher initial laser energy on the powder bed this enables the Zirconia powders to have a higher initial increase in temperature and thermal properties.