For engineers faced with the task of joining nonferrous metals, stranded wire, and many metal alloys, ultrasonic welding is emerging as an option to consider.

It's a cold-phase friction-welding technique that requires no melting, and no high temperature buildup of any kind.

To explain the process and illustrate applications where it works best, engineers at STAPLA (Frankfurt, Germany and Wilmington, MA) decided to write a book on the technology. Afterall, they figured, they were the first to design and build an ultrasonic metal welding system, so who better to write the book on the subject!

The book describes an ideal metal-welding unit, including the generator, welding device, transducer system, anvil, and fixtures. And, it discusses certain welding parameters, such as the influence of welding energy, mechanical stress, and thermal stress. It covers ways to improve the quality of the welds, and discusses the materials suitable for ultrasonic welding.

According to STAPLA, The process applies high-frequency mechanical oscillations to the surfaces being joined, rubbing them together under pressure. The molecules of the surface begin to swirl and intermingle, creating a firm bond.

Besides the book, the company, of course, also designs several ultrasonic-welding products for use in industries such as automotive, appliance, communications, and electronics. Among the latest is the Ultraindexer, which STAPLA calls a precision ultrasonic welder coupled with a linear table. Engineers can program the Ultraindexer to perform multiple weld cycles on the same part or different assemblies.

Sonics & Materials, of Newtown, CT, also designs and manufactures ultrasonic welding equipment. Among their most recent products: the Model 2050 20kHz Ultrasonic Rigid Welder. Its rigidity makes it suitable for demanding applications where minimal deflection is important, the company says. The model has THK rails and bearings, increased throat depth and increased column diameter and wall thickness.

For more information, see www.staplaultrasonics.com