Tarick Walton Global Product Manager Ultrasonics, Branson Welding and Assembly at Emerson
welding: materials
What advances in welding address material variations? Conventional ultrasonic welding technology, using single-parameter weld modes, has enabled electronics manufacturers to achieve high levels of assembly quality and reliability. This is particularly true for products built from rigid, molded plastic components. Ultrasonic welding creates a highfrequency, heat-generating motion between the components to be bonded. It’s been used to join thermoplastics for more than 70 years and has frequently been chosen when parts were too complex or costly to be molded in one piece. Instead, they were molded in multiple parts, which allowed for more efficient and cost-effective welding. This type of welding uses single, weld-parameter modes such as downforce, distance/collapse, depth, time, or energy to manage weld consistency and high repeatability. However, controlling weld quality with single-parameter modes becomes more challenging when assembling plastic parts that are: • Compressible or contain compressible elements • Inserted into substrates that vary in hardness • Installed over or contain sensitive metal or electronic components To assemble hard-to-handle or variable parts, manufacturers have typically had to add an external measuring device to the welder, which allows for the adaptation of a critical weld parameter. This practice adds time, complexity, and cost to the process. Manufacturers facing nextgeneration product assembly challenges
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— from miniaturization to increased electronic contents — require a new range of assembly innovations. Fortunately, advanced technology is offering just that and eliminating the need for external measuring devices. This new, “dynamic mode” for ultrasonic welding
can automatically adjust to respond to part-to-part variabilities and unique materials while avoiding the need to add external measurement or sensing devices. This technique can safely weld small, thin, or complex plastic parts onto plastic structures directly atop sensors or delicate electronics without damage. It can also weld parts atop plastic assemblies containing compressible internal elements, such as elastomeric seals or cores.
As next-generation electronic devices become smaller and lighter, ultrasonic techniques are evolving to create repeatable welds atop delicate components.
Working in dynamic mode The dynamic welding mode can monitor,
December 2021 www.fastenerengineering.com
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