Ultrasonic Riveting For Various Plastics
Ultrasonic riveting is suitable for the connection of plastics to other materials such as metals and to the connection of dissimilar plastics. However, it may not be suitable for the connection of the same plastic, because in this case, the softening head of the pin may be welded to the fitting and form a sharp notch, causing stress concentration and embrittlement of the joint. Contrary to ordinary ultrasonic welding, usually the softer the plastic, the easier it is to ultrasonically rive the joint. However, most plastics achieve good results with the right combination of amplitude and pressure. For best results, ultrasonic riveting is limited to plastics used to melt/soften temperature differences of at least 22 °C. Table 1 lists the ease of ultrasonic riveting of various common thermoplastics.