Abstract: Various implementations of a system for friction based additive manufacturing include a tool head that includes a central axis, a first end, and a second end opposite and spaced apart from the first end along the central axis. The tool head defines a feed channel that extends between openings defined by the first end and the second end. The opening defined by the second end is offset from the central axis of the tool head. The tool head is configured for rotating about the central axis. The system also includes an actuator that is configured to urge a feed material through the feed channel in a direction from the first end to the second end. The second end of the tool head is configured for being disposed adjacent a substrate onto which the feed material is being friction stir deposited.