The difference between ultrasonic welding technology and linear vibration welding technology is that it can be used to weld large as well as 3D-shaped components. This is a friction welding process where thermal energy is transferred by friction between the two halves of the component in the joint area. Compared to the ultrasonic welding process, vibration welding works with much lower frequencies and higher amplitudes, up to 1.8 mm at 240 Hz and 3.8 mm at 100 Hz. Another characteristic is the high welding forces, which, in combination with the parameters already mentioned, allow larger welding areas to be processed. The tool technology therefore plays a very important role due to the powerful forces that are exerted during the joining process.
We apply our extensive expertise in tool design and plastic joining when working with customers to configure the technology for their specific components and applications. Close consideration must be taken to the oscillating upper tool during the design process, and we use Finite Element Analysis (FEA) to confirm stability and ensure it is capable of absorbing the forces generated during the welding process.
The electromechanical drive is excited by a generator installed in the control cabinet. The arrangement in the oscillating head, together with the spring assemblies, enables the springs to be set into linear vibration as a result of the interaction of the magnetic fields. The vibration system can be brought back exactly to the zero position through the return force of the springs and by removing power from the electromagnetic coils.
The Stages of the Vibration Welding Process
- Phase 1: Solid friction (cold drive phase), due to the interfacial friction, the parts to be joined are heated up to the melting temperature.
- Phase 2: Transient melt formation, characterized by a melt film thickness that increases over time, in which the energy input is converted into heat by shearing and friction. The melting gradually increases.
- Phase 3: Stationary phase: the consistency of the melting rate is the feature of this phase.
- Phase 4: Holding pressure and cooling phase.
Application areas in the automotive industry
- Interior, exterior and engine compartment components
- Large welding areas can be achieved
- In general, all thermoplastic materials can be welded. You can find a list here.
- Suitable for virtually all thermoplastics
- Capable of welding large plastic components
- Very short process times possible
- Communication with external sources such as robots, conveyor systems, etc. is possible
- Quick Change tool change procedures