title: Compensation strategy to reduce geometry and mechanics mismatches in porous biomaterials built with Selective Laser Melting.
abstract: The accuracy of Additive Manufacturing processes in fabricating porous biomaterials is currently limited by their capacity to render pore morphology that precisely matches its design. In a porous biomaterial, a geometric mismatch can result in pore occlusion and strut thinning, drawbacks that can inherently compromise bone ingrowth and severely impact mechanical performance. This paper focuses on Selective Laser Melting of porous microarchitecture and proposes a compensation scheme that reduces the morphology mismatch between as-designed and as-manufactured geometry, in particular that of the pore. A spider web analog is introduced, built out of Ti-6Al-4V powder via SLM, and morphologically characterized. Results from error analysis of strut thickness are used to generate thickness compensation relations expressed as a function of the angle each strut formed with the build plane. The scheme is applied to fabricate a set of three-dimensional porous biomaterials, which are morphologically and mechanically characterized via micro Computed Tomography, mechanically tested and numerically analyzed. For strut thickness, the results show the largest mismatch (60% from the design) occurring for horizontal members, reduces to 3.1% upon application of the compensation. Similar improvement is observed also for the mechanical properties, a factor that further corroborates the merit of the design-oriented scheme here introduced.
authors.affiliation: Department of Mechanical Engineering, McGill University, Montreal, QC, Canada H3G 1A4.
authors.forename: Zahra S
authors.initials: ZS
authors.lastname: Bagheri
authors.affiliation: Department of Mechanical Engineering, McGill University, Montreal, QC, Canada H3G 1A4.
authors.forename: David
authors.initials: D
authors.lastname: Melancon
authors.affiliation: Department of Mechanical Engineering, McGill University, Montreal, QC, Canada H3G 1A4.
authors.forename: Lu
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Mechanical Engineering, McGill University, Montreal, QC, Canada H3G 1A4.
authors.forename: R Burnett
authors.initials: RB
authors.lastname: Johnston
authors.affiliation: Department of Mechanical Engineering, McGill University, Montreal, QC, Canada H3G 1A4. Electronic address: damiano.pasini@mcgill.ca.
authors.forename: Damiano
authors.initials: D
authors.lastname: Pasini
mesh_terms: D000497:Alloys; D001672:Biocompatible Materials / Q000032:analysis*; D007834:Lasers; D016062:Porosity; D014025:Titanium / Q000032:analysis; D055114:X-Ray Microtomography
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; C031462:titanium alloy (TiAl6V4); D014025:Titanium
keywords: Additive Manufacturing; Compensation strategy; Geometry mismatch; Mechanical properties; Metallic porous biomaterials