Mechanical properties of hexagonal lattice structures fabricated using continuous liquid interface production additive manufacturing

Davis J. McGregor, Sameh Tawfick, William P. King

Research output: Contribution to journalArticle

Abstract

Additive manufacturing (AM) is a key enabler for architectured lattice materials, because of the geometric complexity of parts that can be produced. Recent advancements in AM have enabled rapid production speeds, high spatial resolution, and a variety of engineering polymers. An open question remains whether production grade AM can accurately and repeatably produce lattice parts. This study presents design, production, and mechanical property testing of hexagonal lattice parts manufactured using continuous liquid interface production (CLIP) based AM. We printed and tested 84 parts, in three polymer materials having relative density ranging from 0.06 to 0.23. Lattice wall structures were reliably printed when truss aspect ratio was in the range 5 to 20 and wall thicknesses were 0.35 or 0.5 mm. The printed lattice parts, each comprising hundreds of slender walls, were measured using high resolution optical scanning. The images were analyzed to evaluate the difference between the printed parts and their designs, and the effect of geometric deviations on the mechanical behavior. The measured elastic moduli of the printed parts are close to the values expected from the materials specifications. The measured strength of the printed parts deviates by 7% from the behavior predicted from the scanned geometry. The failure mode of the printed structures depends upon the material and part geometry. To our knowledge, this is the largest study on the accuracy and performance of AM lattice parts, and the first study of its type for lattice parts made using CLIP.

Original languageEnglish (US)
Pages (from-to)10-18
Number of pages9
JournalAdditive Manufacturing
Volume25
DOIs
StatePublished - Jan 2019

Fingerprint

3D printers
Mechanical properties
Liquids
Polymers
Geometry
Failure modes
Aspect ratio
Elastic moduli
Scanning
Specifications
Testing

Keywords

  • Additive manufacturing
  • Architectured materials
  • Honeycomb
  • Lattice

ASJC Scopus subject areas

  • Biomedical Engineering
  • Materials Science(all)
  • Engineering (miscellaneous)
  • Industrial and Manufacturing Engineering

Cite this

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abstract = "Additive manufacturing (AM) is a key enabler for architectured lattice materials, because of the geometric complexity of parts that can be produced. Recent advancements in AM have enabled rapid production speeds, high spatial resolution, and a variety of engineering polymers. An open question remains whether production grade AM can accurately and repeatably produce lattice parts. This study presents design, production, and mechanical property testing of hexagonal lattice parts manufactured using continuous liquid interface production (CLIP) based AM. We printed and tested 84 parts, in three polymer materials having relative density ranging from 0.06 to 0.23. Lattice wall structures were reliably printed when truss aspect ratio was in the range 5 to 20 and wall thicknesses were 0.35 or 0.5 mm. The printed lattice parts, each comprising hundreds of slender walls, were measured using high resolution optical scanning. The images were analyzed to evaluate the difference between the printed parts and their designs, and the effect of geometric deviations on the mechanical behavior. The measured elastic moduli of the printed parts are close to the values expected from the materials specifications. The measured strength of the printed parts deviates by 7{\%} from the behavior predicted from the scanned geometry. The failure mode of the printed structures depends upon the material and part geometry. To our knowledge, this is the largest study on the accuracy and performance of AM lattice parts, and the first study of its type for lattice parts made using CLIP.",
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