This paper advances the findings of the selective laser melting (SLM) of tool steel and
stainless steel powders. The distinguishing feature is the melting of single layers in deep powder
beds by a continuous CO2 laser. First, effect of process parameters on the surface roughness for
each material is investigated. Based on these results combined with visual observation of the
solidified tracks, the question is then discussed as how the processability of various type of steels
is changed. The results show that surface morphology of layers is affected strongly by scan
spacing, thereby giving a lower average roughness at reduced scan spacing. The effect of scan
speed is also remarkable. In addition, other roughness parameters such as the peak height and
skewness are found to be useful tools for evaluation of laser melted surfaces.Mechanical Engineerin
