The influence of process parameters on vertical surface roughness of the AlSi10Mg parts fabricated by selective laser melting

In recent years, the aluminum alloys parts produced by Selective Laser Melting (SLM) are increasingly used instead of casting aluminum alloys parts in the automotive, aerospace and other fields. However, the high surface roughness of the vertical surfaces is a major issue influencing the application of SLM for aluminum. Moreover, most of the methods to reduce the surface roughness, such as polishing, bead blasting or machining, will increase the production delays and costs. The present study aims at evaluating the effect of linear energy density on the surface roughness of the vertical planes. Both deposited tracks and volumetric specimens were produced and the morphologies and the surface roughnesses were measured. The obtained results indicate that the surface roughness of the vertical planes was reduced to 4 pm from 15 pm when deposited a suitable linear energy density, reducing the surface roughness by more than 70%. The surface morphologies and the height change rate of the deposited tracks had a significant influence on the surface roughness. Furthermore, for experiments with the same linear energy density, the surface roughness was improved with higher laser power.