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Abstract Metal injection molding (MIM) processes are generally more cost-effective for the generation of metallic AM components. However, the thermal processing required to remove the polymer and sinter the metal powder is not well understood in terms of resulting mechanical response and damage evolution, especially in ambient atmospheres where contamination is present. This study aims to provide a range of achievable mechanical properties of copper produced using a MIM-based method called fused filament fabrication (FFF) that is post-processed in a nonideal environment. These results showed direct correlations between sintering temperature to multiple aspects of material behavior. In addition, Nondestructive Evaluation (NDE) methods are leveraged to understand the variation in damage evolution that results from the processing, and it is shown that the higher sintering temperatures provided more desirable tensile properties for strength-based applications. Moreover, these results demonstrate a potential to tailor mechanical properties of FFF manufactured copper for a specific application.
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Development of a Novel, All‐Aromatic High Tensile Modulus Liquid Crystalline Polyimide for Fused Filament Fabrication Applications
Abstract Polyimides (PIs), known for their thermal resistance, chemical stability, and mechanical properties, are often considered challenging materials to process, resulting in limited commercial availability of PIs for melt extrusion, injection molding, and fused filament fabrication (FFF). Currently, material and knowledge gaps prevent the ability to rapidly produce parts from PIs that can be used in high strength and elevated temperature applications. To address this, a novel, fully aromatic PI with thermotropic liquid crystalline properties (LCPI) is successfully synthesized. The synthesized LCPI exhibits better solvent tolerance and thermal stability than commercially available counterparts. The LC phase is confirmed by thermal analysis, wide angle X‐ray scattering, and polarized optical microscopy. Rheological behavior clearly demonstrates that the LC phase reduces melt viscosity. These properties enable the LCPI to be processed into both drawn fibers and filaments for FFF, which is demonstrated alongside an injection molding process. The properties of the printed parts rivaled those made with Ultem 1000, exhibiting an average elastic modulus of 4.16 GPa. The injection molding process resulted in tensile moduli as high as 8.59 GPa and tensile strengths as high as 124.70 MPa. The LCPI polymer demonstrates the desired properties required for aerospace applications via melt processing techniques.
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- Award ID(s):
- 1930277
- PAR ID:
- 10610834
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Functional Materials
- Volume:
- 35
- Issue:
- 24
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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