Evaluation of Support Structure Removability for Additively Manufactured Ti6Al4V Overhangs via Electron Beam Melting

Wadea Ameen,Abdulrahman Al-Ahmari,Muneer Khan Mohammed

doi:10.3390/met9111211

Abstract

The addition of support structures is essential for the successful fabrication of overhang structures through additive manufacturing (AM). The support structures protect the overhang portion from distortions. They are fabricated with the functional parts and are removed later after the fabrication of the AM part. While structures bearing insufficient support result in defective overhangs, structures with excessive support result in higher material consumption, time and higher post-processing costs. The objective of this study is to investigate the effects of design and process parameters of support structures on support removability during the electron beam melting (EBM)-based additive manufacturing of the Ti6Al4V overhang part. The support design parameters include tooth parameters, no support offset, fragmentation parameters and perforation parameters. The EBM process parameters consist of beam current, beam scan speed and beam focus offset. The results show that both support design and process parameters have a significant effect on support removability. In addition, with the appropriate selection of design and process parameters, it is possible to significantly reduce the support removal time and protect the surface quality of the part.

Highlights

IntroductionIn powder-bed-fusion (PBF) processes, such as electron beam melting (EBM), and in selective laser sintering and melting, a thin powder layer is selectively melted using an electron or laser beam [1,2]
Introduction and Literature ReviewAdditive manufacturing (AM) is a manufacturing technique used to fabricate three-dimensional parts in a layer-by-layer manner directly from a computer-aided design (CAD) model.In powder-bed-fusion (PBF) processes, such as electron beam melting (EBM), and in selective laser sintering and melting, a thin powder layer is selectively melted using an electron or laser beam [1,2].Once the powder layer is molten, a new powder layer is spread and melted based upon the CAD data, the steps are repeated until the full component is fabricated
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Summary

Introduction

In powder-bed-fusion (PBF) processes, such as electron beam melting (EBM), and in selective laser sintering and melting, a thin powder layer is selectively melted using an electron or laser beam [1,2]. Once the powder layer is molten, a new powder layer is spread and melted based upon the CAD data, the steps are repeated until the full component is fabricated. The fabrication of structures with overhang geometries that do not contain support structures results in warpage deformation due to the thermal gradient and residual stress. Support structures are essential in the manufacturing of defect-free overhang structures through the PBF process [3]. By facilitating the removal of heat from the structure, support structures prevent part curling, distortion, sagging, cracks, shrinkage, and/or other deformations that result from thermal stresses

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Conclusion