Formation of aluminum alloy parts with working internal cavities by selective laser melting

The great difficulty in synthesizing parts by selective laser melting lies in the formation of high-quality internal surfaces of workpieces. High quality is understood as the absence of defects in the form of shells, pores, partially fused powder granules, forming a rough surface. This task is especially relevant when obtaining parts by selective laser melting of aluminum alloys powders. The main problem is the great complexity or impossibility of their mechanical post-processing. Thus, in the manufacture of parts with working internal cavities used for the flow of liquids and gases, the presence of defects is completely unacceptable. In this paper, we studied the formation of defects in the internal surfaces during the process of obtaining objects by selective laser melting, in particular, the sticking of granules of powder material on the formed surface under various processing conditions. Variable parameters were scanning speed and laser radiation power. Data on the behaviour of the growth of a multilayer object depending on the variable parameters are obtained. The groups of samples of different shapes obtained under different melting conditions are considered.