Center for Ultrasonic Additive Manufacturing

What is UAM?

Ultrasonic additive manufacturing is a solid-state manufacturing process that combines additive joining of thin metal tapes with subtractive milling operations to generate near net shape metallic parts. A rotating sonotrode driven by piezoelectric transducers applies ultrasonic vibrations (>20 kHz) to a foil, creating a scrubbing action and plastic deformation between the foil and the material to which it is being welded, often a metallic baseplate, a part, or other foils. The scrubbing action displaces surface oxides and contaminants while collapsing asperities, exposing nascent surfaces that instantaneously bond under a compressive force. A CNC stage allows for selective material removal and machining to final dimensions, though the low thermal loading in UAM implies that finished parts suffer no distortion, and hence no remedial machining is required.

Schematic of the UAM process and ultrasonic system. Piezoelectric transducers operate in a push-pull fashion. The red arrows depict the motion that occurs during welding.

In UAM of soft alloys (e.g., aluminum, copper), recrystallization and grain refinement are observed in good quality builds within micrometers of the foil interfaces. The UAM system recently installed at The Ohio State University utilizes 9 kW of ultrasonic power, which improves the ability of the process to recrystallize hard materials at the faying interfaces and achieve quality joints of dissimilar materials.

UAM Machine at OSU

Very high power UAM machine installed in the Center for Ultrasonic Additive Manufacturing, which is located in Scott Laboratory.