Effects of Processing Parameters on Surface Roughness of Additive Manufactured Ti-6Al-4V via Electron Beam Melting

Abstract

As one of the powder bed fusion additive manufacturing technologies, electron beam melting (EBM) is gaining more and more attention due to its near-net-shape production capacity with low residual stress and good mechanical properties. These characteristics also allow EBM built parts to be used as produced without post-processing. However, the as-built rough surface introduces a detrimental influence on the mechanical properties of metallic alloys. Thereafter, understanding the effects of processing parameters on the part’s surface roughness, in turn, becomes critical. This paper has focused on varying the processing parameters of two types of contouring scanning strategies namely, multispot and non-multispot, in EBM. The results suggest that the beam current and speed function are the most significant processing parameters for non-multispot contouring scanning strategy. While for multispot contouring scanning strategy, the number of spots, spot time, and spot overlap have greater effects than focus offset and beam current. The improved surface roughness has been obtained in both contouring scanning strategies. Furthermore, non-multispot contouring scanning strategy gives a lower surface roughness value and poorer geometrical accuracy than the multispot counterpart under the optimized conditions. These findings could be used as a guideline for selecting the contouring type used for specific industrial parts that are built using EBM.

Pilot Attempt to Benchmark Spatial Resolution of an Electronic Imaging System Prototype for In-Process Electron Beam Melting Monitoring

“…Minimum electron beam size (mm) 0.200 [23] Spatial resolution without gas, R sp(no gas) (mm) 0.224 The spatial resolution analysis described above was estimated for situations with the absence of gas. However, the Arcam A1 EBM machine operates under helium gas at 2 x 10 -3 mbar [24]. The influence of gas on spatial resolution is thought to be the broadening of the primary machine electron beam.…”

Frontiers of Additively Manufactured Metallic Materials

“…Even if the desired microstructure and mechanical properties are not achieved by adjusting the AM process itself (e.g., modifying the processing parameters [ 44 ]), there are possibilities to improve them after the AM process using post-AM treatments. The other application of post-AM treatments is to reduce manufacturing irregularities or to induce surface-related functionalities that could enhance the performance of AM metallic materials.…”

Surface Roughness Characterisation and Analysis of the Electron Beam Melting (EBM) Process

“…Klingvall Ek et al [33] obtained no influences on the roughness values. Furthermore, Wang et al [34] investigated the effects of producing a contour by using MultiBeam TM or continuous line strategies in order to improve the surface roughness. However, Wang et al [34] established that the process window for improving surface roughness is small, and modifying only the processing parameters has no significant effect on the roughness values.…”