Symmetric ultrasonic rotary horn

The present invention relates generally to ultrasonic welding. More particularly, the invention relates to an ultrasonic rotary horn having tapered axial input sections for the conversion of axial acoustic energy into radial acoustic energy. An ultrasonic rotary horn has tapered input sections for the conversion of axial acoustic energy into radial acoustic energy. The preferred rotary horn includes a first half having a first radial weld section and a first axial input section for receiving a first axial acoustic energy. The rotary horn further includes a second half coupled to the first half. The second half has a second radial weld section and a second axial input section for receiving a second axial acoustic energy. Each half has a coned section defined by an inner tapered surface and an outer tapered surface such that the halves convert a portion of the first and second axial acoustic energy into radial acoustic energy. Each inner tapered surface forms an inner angle with respect to an axis of the horn and each outer tapered surface forms an outer angle with respect to the axis.