Ultrasonic welding Summary Procedure description 1. Introduction 2. Process engineering 2.1. Construction of the joining zones 2.2. The phases of ultrasonic welding 3. Welding types 3.1. Path-dependent welding 3.2. Time-dependent welding 3.3. Energy-dependent welding 4. The process parameters for ultrasonic welding 5. Advantages of ultrasonic welding 5.1. Ultrasound principle 5.2. Sonotrodes 6. Machine technology 7. Application examples Illustration 1 Ultrasonic welding system

1. Introduction The ultrasonic vibrations are produced in a generator, which converts the incoming mains voltage into high-frequency energy. This high-frequency electrical energy is converted into mechanical vibration energy of the same frequency via the transducer (converter). The entire resonance unit consists of a generator, converter, amplitude transformer and sonotrode and operates in resonance. In ultrasonic welding, the heat required for plasticizing is generated by converting ultrasonic vibrations into mechanical vibrations and then transferred to the workpiece to be welded with a certain...

Illustration 2 Energy direction transmitter If there is no energy direction sensor, the welding time is unnecessarily extended. In addition, instead of seam formation, surface welding occurs, resulting in a lack of strength and inconsistency in the welding result. Thermal damage to the material cannot be ruled out either. The pinch weld is preferably used for welding semi-crystalline thermoplastics. However, pinch welds can also be used for amorphous plastics, especially if dense or high-strength welded joints are to be achieved. Illustration 3 Example of the energy direction sensor

2.2. The phases of ultrasonic welding    Start phase: Melting of the energy direction transmitter (ERG) Melting phase: With further heat input, more melt is produced and a complete coupling of the upper and lower part is created. Holding phase: The workpiece is held in a precise position and cools down under holding pressure, during which the horn sags slightly. Welding types 3.1. Path-dependent welding Relative: Stopping the ultrasound is defined starting from the trigger point. Absolute: Stopping the ultrasound is defined from the tool zero position. The drop after the stop due to the holding...

5. Advantages of ultrasonic welding     Ultrasonic welding offers the advantage that three-dimensional weld seams can be realized with short welding cycles. Post-processing of the weld seams is not necessary. Ultrasonic welding is environmentally friendly as no adhesives are required. This means that it can be recycled by type. Ultrasonic welding requires only a fraction of the energy needed for other thermal welding processes. Illustration 4 Components with article hold

5.2. Sonotrodes The sonotrode must be in full contact with the workpiece to ensure optimum sound transmission. Lateral displacement of the workpiece must be prevented by the mounting tool. 6. Machine technology KLN offers the proven Omega III series of standard welding machines with pneumatic drive or servo-electronic drive. Please contact our experts for a solution to your individual welding task.

Pneumatic feed or servomotor-driven Control system Transducer Machine foot

Basic design of a pneumatic ultrasonic welding machine. To ensure that you achieve optimum results, we are happy to put our many years of experience at your disposal when selecting the welding geometry. 7. Application examples Illustration 7 Center console cover Illustration 8 Rivet head after welding Illustration 9 Rivet head before welding

Illustration 10 Charging plug Illustration 11 Charging plug