Ultrasonic metal welding is the most technologically advanced method of bonding non-ferrous metals such as aluminum, copper, nickel, brass, gold and silver.
It has been demonstrated to eliminate most, if not all, of the problems existing in traditional bonding techniques involving the fusion of metal through the application of heat by flame, hot tools, electric current or electric arc in combination with cleaning and fluxing agents and sometimes filler metals.

　　Ultrasonic metal welding is rapidly becoming the process of choice by informed design and manufacturing engineers, because actual applications and operating cost comparisons well illustrate the degree of acceptance and the inherent advantages of ultrasonic metal welding for interconnection applications.

Features and Benefits for Ultrasonic Metal Welding
．Ultrasonic Metal Welding is the ideal process for bonding conductive non-ferrous materials such as copper, aluminum, nickel, brass, gold and silver, similar or dissimilar.
．Excellent welds are achieved even if welding materials are dissimilar in thickness and composition.
．It features fast cycle time, as a typical weld takes only seconds or fractions of a second.
．It is an environmentally friendly process as no solders, flux or braze material are required; no heat is applied, and no consumables are needed; no sparks, fumes or arcs are generated during the welding process.
．Very little energy is expended for a weld. It requires much less energy than that of traditional technologies like resistance welding, and eliminates the need for consumables such as solder, flux, crimp connectors and braze materials.
．It is a cold, friction welding technique without melting the parts and no harmful intermetallics are formed, while a true metallurgical bond is created.
．The ultrasonic weld is extremely reliable, resulting in the highest electrical conductivity.
．Weld tooling typically lasts for several hundred-thousand cycles without need for maintenance.

Ultrasonic Assembly Systems
　　 Ultrasonic assembly systems are generally composed of the following major elements: a power supply, converter, booster, horn, pneumatic press and holding fixture, as detailed in the figure below.

Figure Ultrasonic Assembly systems

Ultrasonic welding principle
　　 When bonding metals through ultrasonic welding, the energy required comes in the form of mechanical vibrations. The mechanical vibrations are introduced in horizontal oscillation direction to the parts to be welded. The principle for ultrasonic metal welding is like follows:

Figure: Ultrasonic metal welding mechanism
　　 During ultrasonic metal welding, a complex process is triggered involving static forces, oscillating shearing forces and a moderate temperature increase in the welding area. The magnitude of these factors depends on the thickness of the workpieces, their surface structure, and their mechanical properties.
　　 The workpieces are placed between the anvil and the horn, which oscillates horizontally during the welding process at high frequency (usually 20 or 35 or 40 kHz). These frequencies are our commonly used frequencies of oscillation and are above human audibility. The 20 kHz one permits the best possible use of energy. 35 or 40 kHz is used for welding processes which require smaller amount of energy.