A process for removing support material from a part made by an additive manufacturing process is disclosed. The part may be arranged in a media filled tank. Ultrasonic waves are directed for the part and/or support material. Ultrasonic waves from an ultrasonic transducer are applied to a part or support material and cause the part to vibrate. The frequency of the ultrasonic energy may be tuned to cause the part and/or the support material to vibrate at its resonant frequency. The support material may have different properties, such as density, geometry, material, or porosity. Such differences may allow the support material to resonate in response to the applied ultrasonic energy waves at a different ultrasonic frequency than, the part itself.