Determining the influence of technological parameters of the electron-beam surfacing process on quality indicators

Abstract

This paper reports the technology and equipment designed for manufacturing parts and components with predefined properties by 3D printing methods. Underlying the technology is the use of a beam of high-power electrons to smelt metal powder in a vacuum chamber with the formation of successive layers that repeat the contours of the digital model of the article. The object of research is the process of surfacing articles from the Ti6Al4Vtitanium alloy powder. The purpose is to determine the optimal surfacing modes based on identifying the effect of process parameters on the quality indicators of articles. The result of the study is the analyzed influence of technological parameters on the properties of articles. The optimum energy density of the beam of 44.5 J/mm3has been determined. Based on the research results, 25 experimental samples were printed. Three beam speed modes were used: 270, 540, and 780 mm/s. For each mode, the dynamic focusing current varied from −1.2 to 1.27 A in increments of about 0.3 A. The articles were carefully examined. A method of raster electron microscopy was used to study the morphology of the samples' surfaces in several zones, namely in the central zone and along the contour; the roughness parameters of the surface micro relief, as well as the presence of defects (pores, non-melting, micro irregularities, inclusions), were established. It has been found that the articles are characterized mainly by a homogeneous micro relief of the profile. The structure of surfaces, formed in different zones depending on technological modes, differs in its morphology. Surfacing modes have been established that have the practical application: beam speed, 780 mm/s; power, 675 W; dynamic focus current, from –1.2 to 0 A. This provides for the minimal parameters of the surface micro relief and the absence of defects such as shrinkage pores, non-melting, as well as a minimum number of inclusions.