There is a significant gap between the properties of materials that are produced using current 3D printing processes and the properties that are needed to support critical space systems. The main limitation for polymers is the interlayer adhesion between layers in the buildup direction. The polyetherimide/polycarbonate (PEI/PC) composite recently demonstrated on the International Space Station is a significant step forward in development for 3D printing in space. However, 3D printing with PEI/PC represents the current practical limits of additive manufacturing (AM) in space due to the temperature requirements to produce other higher-performance materials.
The Phase I SBIR demonstrated the ability to retrofit a simple commercial AM printer with a high-temperature head and low-power laser diodes to enable printing of carbon fiber reinforced (CFR) PEEK, one of the strongest polymers available, along with other polymer formulations like ABS. Increases of up to 240% in tensile strength were demonstrated in the buildup direction using the lasers to provide targeted supplemental heating. Power requirements for the full printer system were 600W, compared to 3,600W and higher for commercial printers coming onto the market that can print PEEK. In this Phase II SBIR, AMI, an ISO 13485-Certified medical device developer and manufacturer, will further develop, test, and commercialize the CFR PEEK composite feedstock and printer retrofit approach, with improved strength through focused photothermal polymerization. Penn State experts on 3D printing, polymer formulation and the effects of thermal history on 3D printed part strength will participate in the project. A local company with expertise in compounding PEEK, will collaborate with the team to produce feedstock ready for 3D print with enhanced layer adhesion.
Additive manufacturing of high performance thermoplastics provides a unique opportunity to enable in situ production of: a) large aerospace structures that not possible with terrestrial manufacture and delivery b)devices or structures on other planetary bodies, and c) temporary, on-demand tools and items capable of being recycled and reused by astronauts.
Additive manufacturing of CFR PEEK to produce: 1) custom orthotics, 2) molds for injection molding, and 3) implantable PEEK devices (orthopedics) due to biocompatibility history of PEEK and better match to mechanical properties of bone compared to metals. The medical effort requires conducting quality activities like Verification and Validation on parts printed individually.