In ultrasonic welding (USW), the faying surfaces of the two components are subjected
to a static normal force and oscillating shearing (tangential) stresses. The
shearing stresses are applied by the tip of a transducer , which is similar
to that used for ultrasonic machining. The frequency of oscillation
is generally in the range from 10 to 75 kHz, although a lower or higher frequency
can be employed. Proper coupling between the transducer and the tip (called-by
analogy with electrode-a sonotrode, from the word sonic) is important for efficient
operation.