Comparison of Laser Power and Scan Speed in SLM

Abstract

With the rapid development of selective laser melting technology, the effect of different process parameters on the quality of the printed parts was studied by many researchers in recent years. In this work, a comparison on the effect of laser power and scan speed which was considered as two main factors to affect laser power density, was studied. An inner structure part with overhanging surface was designed and printed to better study the influence on the surface quality caused by these two factors. The testing results revealed that with the same energy density, different performance can be observed on the overhanging and side surface quality caused by laser power and scan speed. With the increasing of the laser power, side surface roughness value showed an increasing trend due to the increasing of the temperature gradient of the molten pool while the overhanging surface quality had a descending trend. It was mainly due to the fact that to keep the same laser power density, the scan speed decreased which resulted to the increasing time for solidification of the molten pool. This phenomenon lead to the increasing of the sinking distance and the overhanging surface quality showed a decline trend.