Fast joining of instrument clusters using ultrasonics

With ultrasonics it is possible to solve a variety of joining tasks for instrument clusters. The weld tasks are just as individual as the design itself: Dust-free welding of cover slips to front frames, gap-free staking of chromium-plated trim rings or distortion-free joining of display plates. Ultrasonic welding is particularly suitable for parts with complex shapes and different weld zone positions.

In comparison with other joining processes, such as vibration and laser welding, the ultrasonic joining technology can score highly. With cycle times of less than 10 seconds it is possible to weld cover slips (made of PMMA and partly equipped with hot-embossed rims) onto support frames accurately and distortion-free. With weld processes of only half a second it is possible to achieve high-strength joints mark-free and lint-free. Energy is focused specifically in the area specifically designed for ultrasonic welding and thus prevents undesired component distortion. No additional consumables, such as adhesives or screws are required for ultrasonic welding. Specially conditioned plastics are not required, either. In comparison with clipped components, the ultrasonic process ensures creak-free connections and saves costs in terms of sophisticate tool structures. Even for difficult-to-access joining points or component surfaces with 3D contours, it is possible to develop suitable weld tools (sonotrodes) for safe production with the help of FEM calculations (finite element method).

Meanwhile, ultrasonic welding of instrument clusters is no longer limited to cover slips but day-to-day applications also include trim elements, such as chromium rings or complete cover frames and display plates. For these types of applications, ultrasonic staking with 35 kHz is used as a general rule. In contrast to classic ultrasonic welding, i.e. two plastic surfaces are joined, ultrasonic staking involves plastic material that is plasticized and added to the staking point so that it is possible to form the stake head.

However, to realize impeccable and secure ultrasonic weld joints, the component design must be suitable for ultrasonic processing. It is by no means more complex than for other joining processes but represents a basic requirements for successful welding. Key features of a good ultrasonics supplier is detailed preliminary consulting as well as competent support and customer services during the implementation process.