Glossary of Ultrasonic Welding Terms
Booster: a mechanical transformer used to increase or decrease the amplitude of the horn.
Far field weld: refers to a weld where the distance between the contact surface of the horn and the weld joint is more than 1/4 inch. Ultrasonic energy is transmitted through the upper portion of the part to the joint surface.
Filler: an inert substance added to a resin to modify its physical properties.
Frequency: the number of cycles per second, measured in hertz.
Gain: the ratio of output amplitude to input amplitude of a horn or booster.
Horn: an acoustical tool that transfers mechanical vibrations from the transducer and booster to the parts to be assembled.
Near field weld: refers to a weld where the contact surface of the horn is 1/4 inch or less away from the joint surface. It is important that the horn fits the exact contour of the part to be welded.
Nodal point: the point or points in a booster or horn where little or no linear motion occurs.
Staking: the melting and forming of a plastic stud to retain or lock another material (often dissimilar) in place.
Swaging: used to capture another component of an assembly by melting and reforming a ridge of plastic around the component. The ridge locks the second component in place without welding the two materials together.
Thermoplastic resins: material that can be repeatedly softened and reshaped with heat and pressure. They are ideal for ultrasonic welding.
Thermoset resins: material that cannot be melted or reformed. Hard and brittle, they are not suitable for ultrasonic welding.
Transducer: a piezoelectric device that converts high-frequency electrical energy into high-frequency mechanical vibrations.
Ultrasonic welding: an assembly process in which parts are joined by the local application of pressure and high-frequency vibratory energy.