Wire-based additive manufacturing using an electron beam as heat source

Abstract

Many standard welding processes, such as gas metal arc-, laser-, or electron-beam welding, can be used for additive manufacturing (AM) with only slight adaptions. Wire-based additive manufacturing provides an interesting alternative to powder-based processes due to their simplicity and comparatively high deposition rates. The use of an electron beam as heat source for AM offers unique possibilities for construction of components due to its inherent flexibility. It is possible to efficiently build bigger parts with comparably fine features and high complexity. Furthermore, additional working steps such as preheating, surface modification, welding, or heat treatments can be implemented into the additive manufacturing process and thereby alleviate the bottleneck of the evacuation of the vacuum chamber. Aside from this, the ultra high vacuum atmosphere can be beneficial, when working with reactive materials such as Ti or Mo. The intrinsic complexity of electron-beam additive manufacturing (EBAM) can make a stable and reproducible process control quite challenging. In this study, the influence of the main process parameters, such as heat input, energy distribution, wire feed, and their complex interactions are investigated. Based on single beads on a mild steel substrate using an unalloyed metal core wire (G4Si1), the correlation between the process parameters such as beam current, acceleration voltage, speed, wire feed rate and position, and the resulting bead geometry, height, width and penetration was studied. These findings were used to successfully establish a multi pass layout consisting of one to six beads next to each other and up to ten layers in height. For basic characterization, metallographic analysis as well as hardness measurements were performed.

Additive manufacturing – a general corrosion perspective

“…The hardness of wire-fed electron beam additively manufactured structures have been demonstrated to vary locally throughout the microstructure, with the hardness map being useful in understanding the local variations [8]. The hardness varied between 150-300 HV1, with the surface and the bulk showing alternating hardness values, with no clear position attributable to low or high hardness [8]. Little modifications in the AM process, such as energy input or wire-feeding speed or angle, had a large influence on the hardness, also affecting the hardness 'pattern' in the material [8].…”

VLIJaNIE TRAEKTORII 3D-PEChATI CILINDRIChESKIH OBRAZCOV TITANOVOGO SPLAVA VT6 NA IH STRUKTURU I MEHANIChESKIE SVOJSTVA

“…Напротив, проволочные подходы предлагают меньшую точность изготовления, но позволяют получать крупногабаритные изделия, которые в последствии могут быть подвергнуты минимальной механической обработке. При этом в работах [1,2] отмечается, что при использовании проволочных методов, стратегия печати, в том числе ее траектория, может оказывать влияние на процесс формирования изделия.…”

Mathematical modeling of the electron-beam wire deposition additive manufacturing by the smoothed particle hydrodynamics method

“…The technology of electron-beam wire additive manufacturing (Lorenz et al 2015;Ding et al 2015;Stawovy 2018;Fuchs et al 2018;Fortuna et al 2018;Tarasov et al 2018) uses an electron beam to melt wire filler material. In the process of layer-by-layer melting, a workpiece is manufactured for subsequent processing.…”