Statistical Investigation of the Surface Roughness of Ti-6Al-4V Products Built by Selective Electron Beam Melting

The paper presents the results of a statistical study of the parameters of the microgeometry of the surface of the vertical walls of the construction objects during additive shaping via electron beam melting. An assessment was made of the influence of the construction condi-tions and the hatching mode parameters on the surface roughness. The influence of the hatching mode parameters on the roughness of the side surface, when constructing samples with vertical walls, was established. It is shown that the value of the average size of the height of the irregularities Rz increases with the intensification of the energy regime of hatching. A physical model is proposed that describes the influence of the hatching mode on the roughness of vertical walls, based on the hypothesis of a possibility of penetration of the melt micro-flow during hatching onto the outer surface of the contour. It is shown that the distribution of the surface roughness values of the vertical walls has a non-Gaussian character, the curves are, as a rule, right asymmetric (the mode is located to the left of the size grouping center), which indicates the influence of non-random factors, the number or values of which systematically change over time.