If Polyethylene (PE) is the material and part dimensions are large, the demands on the joining technology grow. In this case the medical container also had to be Ieak-proof and satisfy requirements for validated and traceable welding processes.
PE is a very soft plastic that has high dampening effect to the ultrasonic vibrations. As a result, welding amplitudes have to be bigger than 40 µm in order to melt the material. Before there were ultrasonic generators capable of delivering such high power with long-term reliability, it was not possible to handle such welding applications by ultrasonic. Difficult jobs of this type are often realized utilizing hot plate welding. However, this technology does not provide sufficient quality-relevant process data to satisfy the high production requirements. In this case, the project was successfully completed by using ultrasonic welding technology.