Overlay

The principle of energy focusing

The secret of ultrasonic welding is focusing the ultrasound with an energy director. In this way, it is possible to generate heat and subsequently melt, restricted to a locally defined area, while using only little energy. Large-area contact surfaces are counterproductive; they require high power and only achieve undefined joining areas with poor strength.

Energy focusing is achieved by:

  • the energy director (ED)
  • sonotrode design
  • contouring of the anvil profile

 

 

 

Energy focusing through  weld geometry
Energy focusing through  weld geometry

Possibilities of energy focusing due to variations in the joint design

Energy focusing through sonotrode
Energy focusing through sonotrode

Possibilities of energy focusing due to variations in sonotrode design

Focusing by the sonotrode shape (weld tool); e.g. during the ultrasonic staking process, the sonotrode assumes the task of energy concentration.
The centering tip serves as melting initiation aid.

Energy focusing through anvil structure

Possibilities of energy focusing due to variations in anvil structures

Focusing by means of contouring of the anvil structure for web materials such as film, cardboard, and nonwovens. Local deformation is achieved by anvil or sonotrode contours.

BASICS of PLASTICS

PDF, 376 kB BASICS of PLASTICS in download cart file in download cart