Riveting with ultrasonics is a wide-spread application used when you have to joint thermoplastic materials with materials of different nature.
The operation principle is based on localized heat production by mechanic vibrations.
Usually this technique is utilized when you have to joint together plastics and metal.
The sonotrode has to be designed and manufactured in the way to house and shape the material which melts giving
itself the characteristic rivet shape. With special sonotrodes you can make at the same time multiple riveting.
The principle rules to be observed during riveting are the following:
- the pin base has to be rounded to avoid its breaking during vibration
- the sonotrode feed speed towards the part has to be slow
- the thrust pressure has to be slow. The progressive plasticization which takes place under low and continuous pressure, forms the stop cap.
- the ultrasonics have to intervene before the sonotrode touches the part
- the pause time after the vibrations has to be sufficiently long to permit the material to cool down.