Assembly Considerations

The laser welding process uses a laser beam that passes through one component and melts the surface of the second component at the welding interface. The first component, made of a material that lets the laser pass through without heat generation, is known as the transmissive component. The component absorbing the energy is either made of an absorptive material or has an absorptive material at the interface. Modern laser welding technology enables the illumination of the entire welding surface instantly, instead of the old technology that relied on scanning the weld area.

Some of the positive attributes of laser welding are:

No relative motion between the parts, only the weld area is heated and melted as in induction welding but without the need of a third component such as a preform
Fast weld times, typically from 1 to 5 seconds
Allows preassembled components to be welded, maintaining the same position and orientation
Allows accurate control of power dissipation at the joint interface by varying the power of the laser source producing a weld with less flash
No particulate matter. Eliminates the fear of particulate contamination in delicate medical and sensitive electronic products
Suitable for a large variety of amorphous and semi-crystalline thermoplastics
Can be used with a limited selection of dissimilar material combinations.

And the negative attributes are:

Combination of transmissive and absorptive materials is absolutely necessary
With increase in thickness, transmissibility diminishes, rendering even the transmissive materials unsuitable for laser welding if they are too thick
Material to be melted must be absorptive to the laser beam. To make normally transmissive material absorptive, special additives packages have to be added to the formulations, or the surface has to be coated with absorptive inks
Laser welding equipment is expensive

[ Close This Window ]