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Metal additive manufacturing may be limited by build volumes (i.e., it can be hard to make large parts), post-processing requirements, and upfront costs to buy capital equipment. The two NASA-developed technologies are add-on tools for FSW systems (reducing costs), do not require a printer or print bed, and produce parts with high quality surface finishes. The C-FSD attachment includes a non-rotating block through which the C-FSW rotating pin is threaded, and a containment plate to hold the plasticized metal within the system. In this technique, raw metal feedstock is fed into one end of the non-rotating block, is heated and plasticized by the C-FSW pin, and is driven out the other side of the block. The C-FSW pin is used to join the new material to the pre-existing layer. The B-FSD tool uses a dual-shoulder design to print outward from the edge of the base panel. The B-FSD process uses the same feed system as the C-FSD, but utilizes the bobbin/SR-FSW pin's dual shoulders (i.e., containing the metal on both the top and bottom) enabling more complex structures to be made, and the ability to print varying thickness depositions in a single pass. The Additive C-FSD and B-FSD end effector tools are both at technology readiness level (TRL) 4 (component and/or breadboard validation in laboratory environment) and are available for patent licensing.

The invention consists of a 3D print head apparatus that heats and extrudes a regolith-polymer (or other) mixture as part of an additive manufacturing process. The technology includes a securing mechanism, hopper, nozzle, barrel, and heating system. The securing mechanism attaches to a wrist joint of a robotic arm. The hopper, connected to the securing mechanism, has a cavity and a lower aperture. The barrel is an elongated, hollow member with its first end connected to the hopper's lower aperture and its second end connected to the nozzle's upper aperture. The heating system is positioned along the barrel and comprises a heater, thermocouple, insulator, and heating controller. The heating controller activates the heater based on input signals received from the thermocouple. The print head apparatus also includes a feed screw, drive shaft, and motor. The feed screw is positioned within the elongated hollow member of the barrel, and the drive shaft transmits torque to the feed screw. The motor provides torque to the drive shaft. An agitator is secured to the drive shaft, facilitating the consistent movement and mixing of the regolith-polymer mixture in the hopper. The nozzle includes a tube with an open end and an occluded end, allowing the mixture to be extruded through the lower aperture. The jointly developed 3D print head technology enables efficient, large-scale additive construction using in-situ resources, such as regolith or other materials. The innovation reduces the need for transporting materials from Earth and allows for sustainable habitat development on the Moon or Mars. Given its adaptability to different crushed rock-polymer materials, the invention may also serve as an alternative to conventional Portland concrete construction on Earth.