Mechanical properties of tissue-mimicking composites formed by material jetting additive manufacturing.

Capitalizing on features including high resolution, smooth surface finish, large build volume, and simultaneous multi-color/multi-material printing, material jetting additive manufacturing enables the fabrication of full-scale anatomic models. The ability to print materials that resemble relevant, compliant tissues has especially motivated implementation of material jetting for patient-specific surgical planning or training models. In an effort to broaden the material selection for the material jetting process, and to provide materials that more closely mimic the functional needs for a wider variety of tissues, a composite material system is explored that uses non-curing fluid dispersed into a photo-curable medium. The material properties of the composites are examined through both thermal and mechanical analysis (dynamic mechanical analysis, Shore hardness testing, puncture testing, and tensile testing). Higher contributions of non-curing fluid generally reduce part strength and stiffness, and exponential and second-order polynomial expressions are appropriate fits for many of the mechanical properties as functions of non-curing fluid concentration. Through the fundamental exploration of the impact of an added diluent on material properties, the study advances knowledge on the process-property relationship for multi-material jetting. Additionally, better understanding of the mechanical property space offered by these materials will expand the capabilities of material jetting in the context of biomedical applications. The collection of mechanical properties serve as reference data sets to facilitate quicker screening for tissue-mimicking, medical models.
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