Surface characterization of powder-bed fusion 3D-printed metal parts

• Main Author: Chan, Ethan
• Other Authors: Tan Xipeng
• Format: Final Year Project
• Language: English
• Published: 2018
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/74700
• Institution: Nanyang Technological University

Electron beam melting (EBM) is a subset of the powder-bed fusion metal additive manufacturing process. The biomedical and aerospace industries and many others use this technology to print complex functional components to meet its stringent requirements. This technology often requires post-processing techniques to achieve its final desired properties (i.e. surface finish). While earlier studies on powder-bed fusion processes focused on the microstructures, mechanical properties, and printing parameters, research on surface characteristics of on powder-bed fusion metal printed parts are limited. Despite the advantage to print complex geometries with high density and mechanical properties, relatively rough as-printed surface still poses a major issue for EBM -printed parts. This project aims to study the surface characterization (i.e. surface roughness, waviness, texture, and flaw) of EBM printed metal parts of basic geometries. Fine spherical stainless steel (SS)316L powder (25 - 63 µm) was used to print designed geometrical shapes such as a cube, pyramid, cylinder, semi-cylinder, hemisphere, cone and a truncated cone. The surfaces of each EBM-printed parts were then measured using a laser scanning 3D confocal microscope followed by image processing and filtering. Surface roughness measurement involved the use of high pass cut-off filter of λ_c=8 mm and low pass cut-off filter of λ_s = 0 mm, the parameters used for the 2D surface profile analysis were Ra, Rp, Rv, and Rz. Waviness measurement involved the use of λ_c=0 mm and low pass cut-off filter of λ_s = 0 mm, the parameters used for the same 2D profile were Wa, Wp, Wv, and Wz. Surface texture and flaw were observed by area mapping dependent on geometry surface constraints. The results and conclusions allow readers to have a better understanding of the surface characteristics of powder-bed fusion 3D-printed parts, in particular using EBM technology.