Impact behavior and fractography of additively manufactured polymers: Laser sintering, multijet fusion, and hot lithography

Abstract

To reduce the lead time, polymer fuel tanks could be toollessly produced using additive manufacturing (AM) technologies. Detailed knowledge of the performance of AM polymers is essential for the design and development of such components. In instrumented static (0.01 mm/s) and dynamic (2.5 m/s) three-point bending and puncture tests, the impact behaviors of polyamide and methacrylate-based photopolymer test specimens were compared. The polyamide test specimens were produced by laser sintering and multijet fusion, and the photopolymer test specimens were produced by a hot lithography process. Fractography was performed using stereo light and scanning electron microscopy to investigate the fracture surface morphology. The test results were used to analyze the relationships among the surface roughness, shear modulus, and glass transition temperature. The AM polymers revealed comparable force–displacement behaviors in a static three-point bending test, but their impact behaviors differed greatly. The obtained results highlight that the impact performance of AM polymers is an essential design variable for fluid-containing parts.