Laser Welding
With the various transmission techniques of laser welding, it is possible to weld almost any shapes. The heat is introduced to join the plastics by laser beams.
Highly transparent thermoplastics with good absorption in the layers close to the surface are ideal for laser welding. The plastics being welded should also have adequate polymer compatibility, low reflection factors and melting temperatures at the same level. The process also offers the facility to weld together combinations of hard and soft plastics.
During welding, the laser beam penetrates the laser-transparent plastic and strikes the absorbent plastic. Both plastics are then plasticised. After cooling, the welding process is complete.
Principle of laser welding
- Laser-transparent plastic
- Beam source: Diode laser, Nd:YAG laser
- Absorbent plastic
- Clamp
The three methods of transmission welding using laser are described below.
Contour laser welding
The laser beam traces the contour to be welded.
- Advantages:
- Flexible system
- Easy to change geometry
- Disadvantages:
- Guide system needed for the tool
- Process time depends on weld length
- Restrictions on the size of process surface
- Restrictions in part geometry
Simultaneous laser welding
Several
laser beams weld the contour simultaneously.
- Advantages:
- Short process times
- No guide system needed for the tool
- Disadvantages:
- New tool needed for geometry changes
- Restrictions in part geometry
- Capital costs increase with component size
Quasi simultaneous laser welding
The laser
beam is emitted via a scan mirror so that the contour is completely irradiated.
- Advantages:
- Short process times
- No guide system needed for the tool
- Flexible system
- Easy to change geometry
- Disadvantages:
- Restrictions on the size of process surface
- Restrictions in part geometry
SONOTRONIC designs and manufactures machines for laser welding, for example, for welding blood diagnosis systems (medical engineering), car bumpers, exhaust testing systems (automotive industry) or plastic trims of electronic consumer goods (electronics and electrical engineering).
