SBIR-STTR Award

We propose to create an open-source modification of our commercially available, affordable, industrial 3D printer, and in conjunction develop printable, high temperature hybrid thermoset (HT2) materials in partnership with the University of Tennessee at Knoxville (UTK) during this Phase 1 NASA/STTR. In addition to additive manufacturing’s (AM) benefits of low-cost prototyping, efficient low volume manufacturing, and unparalleled ability to create complex geometries, utilizing the Gigabot platform offers scalability as research progresses to enable affordable and large-scale printing of TPS. The methodology proposed will have the potential of expanding the thermoset extrusion material library and significantly decrease the time spent on previous TPS systems. In collaboration between re:3D and UTK, HT2 Materials will be developed, and 3D printed with the target application of TPS for space vehicles. The TPS materials and methods will allow for optimum performance of extreme materials, making it possible to print them in more complex and contoured geometries to enable maximum heat shielding performance in space vehicular applications in launch and recovery. This will involve the formulation of a three-phase, low-density, epoxy-polysilazane based syntactic foam, including high-alumina cenospheres and nanoclay reinforcement. The optimum material formulation will be paired with the CNC controlled movement of an extrusion head to enable tailored density and porosity control coupled with long pot life and several curing options to meet post-processing constraints. Various geometries will then be tested to demonstrate the optimized 3D printing parameters and resolution. The various parts that will be designed and fabricated will then be tested for their thermo-mechanical properties, extreme heat and flame resistance, and charring and ablation properties. Anticipated

Benefits:
The development of a variety of termoset materials capable of withstanding the rigors of space for use in TPS creation. The ability to use open-source additive manufacturing tools for the creation of tool-path algorithms, for printing directly onto the face of three dimensional objects for the creation of TPS. Time and Money savings from using additive manufacturing for TPS creation. Scalability of the solution as the project progresses to incorporate large build/surface areas. Private-commercial space industry is growing exponentially, and TPS creation through Additive Manufacturing, would prove to be useful for customers in this sector. TPS creation could be useful to other space agencies and DoD partners. There are also a whole host of opportunities to learn more within the R&D effort for technologies to be incorporated into future iterations of re:3D's 3D printers.

Based on the knowledge and expertise gained in partnership with the University of Tennessee at Knoxville (UTK) during the NASA/STTR Phase I work, re:3D proposes the development of a pilot system for the deposition of a phenolic foam TPS surface onto a scaled demonstration article in parallel with refinements and improvements to the foam’s material characteristics.The Phase II research activities at UTK will focus on understanding the processing requirements to scale up production of the foam feedstock to 3D print large-scale test articles, refine the foam to further lower density and increase temperature stability, explore novel printing approaches to tailor effective density and elastic modulus and/or incorporate graded composition to raise temperature stability at the outer surface, and continued plasma arc jet torch testing of the developed materials and architectures.During Phase II, re:3D will be responsible for designing, developing and building the systems and mechanisms required for a pilot material extrusion system of the phenolic foam onto a scaled demonstration article consisting of an aluminum dome with a radius of curvature of approximately 1 meter and a 1-meter base diameter. The system would be comprised of the following elements: Mixing of the foam components, either outsourced or performed in-house as determined by a feasibility study during the course of the Phase II investigation at UTK Transport of the foam from the mixing containers to the deposition nozzle through the use of an appropriate metering pump Conformal deposition of the foam onto the aluminum dome with in-situ defect monitoring and advanced motion planning using a gantry printer based on re:3D’s existing Terabot platform and a custom-designed extruder with added degrees of motion Curing of the foam in an appropriate industrial oven Post-process machining to achieve the final desired finish of the TPS surface Anticipated

Benefits:
This process has applicability mission requiring an EDL phase dependent on parasitic surfaces for spacecraft survival. Current methods are expensive, labor intensive and result in non-optimum layering. In addition to cost benefits through material savings and automation, AM application of TPS surfaces offers real-time component certification, integration of sensors into the TPS during fabrication, & implementation of digital thread paradigms where TPS surfaces are generatively designed around engineering requirements. Outside of research institutions, to our knowledge there are no commercially available large-scale printers capable of applying thermoset foams to conformal, non-planar surfaces. With the resources of a Phase II grant, our collaboration with UTK, and partnerships with industry, we believe this project is achievable and will result in a process to industries beyond space and DoD customers.