Page 194 - IJB-9-4

International Journal of Bioprinting

RESEARCH ARTICLE
Metrological characterization of porosity

graded β-Ti21S triply periodic minimal surface
cellular structure manufactured by laser powder

bed fusion

Lorena Emanuelli *, Raffaele De Biasi , Anton du Plessis , Carlo Lora ,
3,4
5
1
2
Alireza Jam , Matteo Benedetti , Massimo Pellizzari 2
2
2
1 INSTM (Operative center: University of Trento), Trento, 38123, Italy
2 Department of Industrial Engineering, University of Trento, Trento, Italy
3 Research Group 3D Innovation, Stellenbosch University, Stellenbosch, South Africa
4 Object Research Systems, Montreal, Canada
5
SISMA SpA, Piovene Rocchette, Vicenza, Italy
(This article belongs to the Special Issue: 3D Printing of Advanced Biomedical Devices)
Abstract
The design of a functionally graded porous structure (FGPS) for use in prosthetic
devices is crucial for meeting both mechanical and biological requirements. One of
the most commonly used cellular structures in FGPS is the triply periodic minimal
surface (TPMS) structure due to its ability to be defined by implicit equations, which
allows for smooth transitions between layers. This study evaluates the feasibility of
*Corresponding author: Lorena using a novel β-Ti21S alloy to fabricate TPMS-based FGPS. This beta titanium alloy
Emanuelli exhibits low elastic modulus (53 GPa) and good mechanical properties in as-built
(lorena.emanuelli@unitn.it) condition. Two TPMS FGPSs with relative density gradients of 0.17, 0.34, 0.50, 0.66,
Citation: Emanuelli L, De Biasi R, and 0.83 and unit cell sizes of 2.5 mm and 4 mm were designed and fabricated using
du Plessis A, et al., 2023, laser powder bed fusion (LPBF). The as-manufactured structures were analyzed using
Metrological characterization of
porosity graded β-Ti21S triply scanning electron microscopy (SEM) and X-ray micro-computed tomography (µ-CT),
periodic minimal surface cellular and the results were compared to the design. The analysis revealed that the pore size
structure manufactured by laser and ligament thickness were undersized by less than 5%. Compression tests showed
powder bed fusion. Int J Bioprint,
9(4): 729. that the stabilized elastic modulus was 4.1 GPa for the TPMS with a 2.5 mm unit cell size
https://doi.org/10.18063/ijb.729 and 10.7 GPa for the TPMS with a 4 mm unit cell size. A finite element simulation was
performed to predict the specimen’s elastic properties, and a lumped model based
Received: January 09, 2023
Accepted: February 28, 2023 on lattice homogenized properties was proposed and its limitations were explored.
Published Online: April 7, 2023
Copyright: © 2023 Author(s). Keywords: Functionally graded porous structures; Ti-21S; Skeletal-based triply
This is an Open Access article
distributed under the terms of the periodic minimal surface structure; Metrological characterization; Laser powder bed
Creative Commons Attribution fusion; Additive manufacturing
License, permitting distribution,
and reproduction in any medium,
provided the original work is
properly cited.
1. Introduction
Publisher’s Note: Whioce
Publishing remains neutral with The mechanical and osteogenic properties are of primary importance in the selection of
regard to jurisdictional claims in a biomaterial and in the design of an implant. The main requirements for a biomaterial
published maps and institutional
affiliations. include biocompatibility, high corrosion and wear resistance, high osteogenic response,

Volume 9 Issue 4 (2023) 186 https://doi.org/10.18063/ijb.729