Improving fracture strength of fused filament fabrication parts via thermal annealing in a printed support shell
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Polymeric structures fabricated using fused filament fabrication (FFF) have limited use in engineering applications as a result of their poor inter-laminar bonding. In this study, we utilize a dual-material print head to encase a low glass transition temperature (Tg) polymer (acrylonitrile butadiene styrene) within a high-Tg shell (polycarbonate). The resulting structure, if annealed at a temperature between the core and shell polymer Tg values, creates a tough interior with high inter-laminar strength while retaining the as-printed three-dimensional geometry of the part. Fracture toughness of annealed, shelled parts was evaluated using single edge notch bend (SENB) fracture specimens and reached values more than 1800% higher than unannealed specimens. Importantly, the annealed specimens exhibited consistent ductile failure and plastic deformation, unlike the as-printed parts which exhibited brittle inter-laminar fracture. Parts with complex geometries are presented to demonstrate geometric stability during annealing and a practical load bearing application.
KeywordsAdditive manufacturing Fused deposition modelling Fracture mechanics Annealing
This research was supported in part by an appointment to the Postgraduate Research Participation Program at the U.S. Army Research Laboratory administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the U.S. Department of Energy and USARL.
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Conflict of interest
On behalf of all authors, the corresponding author states that there is no conflict of interest.
- 5.Yerazunis WS, Barnwell III JC, Nikovski DN (2016) Strengthening ABS, nylon, and polyester 3D printed parts by stress tensor aligned deposition paths and five-axis printing. In: Proceedings of the Solid Freeform Fabrication Symposium, AT&T Conference Center, Austin, Texas, pp 1259–1271. http://sffsymposium.engr.utexas.edu/TOC2016, http://sffsymposium.engr.utexas.edu/sites/default/files/2016/102-Yerazunis.pdf
- 9.Roschli AC, Duty CE, Lindahl JM, Post BK, Chesser PC, Love LJ, Gaul KT (2018) Increasing interlaminar strength in large scale additive manufacturing. Conference: 29th International Solid Freeform Fabrication Symposium—Austin, Texas, United States of America—8/13/2018 4:00:00 AM-8/15/2018 4:00:00 AM.; Oak Ridge National Lab. (ORNL), Oak RidgeGoogle Scholar
- 11.Rodriguez JF (1999) Modeling the mechanical behavior of fused deposition ABS polymer components. University of Notre Dame, Notre DameGoogle Scholar
- 14.Lužanin O, Movrin D, Plančak M (2014) Effect of layer thickness, deposition angle, and infill on maximum flexural force in FDM-built specimens. J Technol Plast 39(1):49–58Google Scholar
- 19.Huang B, Singamneni S (2012) Alternate slicing and deposition strategies for FDM of light curved parts. J Achiev Mater Manuf Eng 55(2):511–517Google Scholar
- 23.Tyson E How to anneal your 3d prints for strength. https://rigid.ink/blogs/news/how-to-anneal-your-3d-prints-for-strength. Accessed Nov 2018
- 27.ASTM (2015) ASTM E1820-15a—standard test method or measurement of fracture toughness. https://doi.org/10.1520/e1820-15a
- 28.PC Data Sheet (2017) Stratasys, Ltd. https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahUKEwjB6NucxLnhAhVqUt8KHS3uAFsQFjAAegQIABAC&url=https%3A%2F%2Fwww.stratasys.com%2F-%2Fmedia%2Ffiles%2Fmaterial-spec-sheets%2Fmss_fdm_pc_1117a.pdf&usg=AOvVaw1NPJpFdA15rhVAOseePkaS