Two decades ago, laser welding was seen as an exotic process, only used in very few instances where absolutely no other method of welding would be suitable. Today, thanks to advancements in technology and increased affordability, laser welding has become an integral part of the metalworking industry.
Welding is the process of heating two materials into a molten state to fuse them together. Using lasers to generate light energy, materials then absorb this energy, which is then converted into heat energy. Using a light beam either in the visible or infrared segment of the electromagnetic spectrum, this energy can be transmitted from the source material using delivery optics. The optics then focus and direct the energy into a very tiny and exact point.
Because a laser emits coherent radiation, the beam of energy will have very little, if any divergence. The power supply of a laser has the capability to deliver a pulse of light that has not only accurate, but repeatable energy and duration. When the beam of the laser is focused onto a small spot, the density of the energy becomes much larger. Another added benefit is that a laser beam can travel a large distance without losing a significant amount of energy or weakening the quality of the beam.
The light that is absorbed causes what is known as a “keyhole” effect. This means the focused beam essentially acts as a drill, which vaporizes and melts selections of the metal. As the pulse of the laser ends, the metal that has been liquefied then flows back in toward the keyhole. As the metal solidifies it creates a small spot weld. While the process can seem complex, it can be completed in milliseconds.
Because the laser has the ability to fire pulses one right after another, seams can be created quickly and efficiently. Moving the work piece or optics allows anything from individual spot welds to multiple overlapping spot welds to create a seam weld that can be structural or hermetic.
There are certain applications where traditional methods of welding simply cannot perform to high enough standards. Materials such as copper, aluminum and titanium are very difficult to weld due to the fact that these metals have a lower melting point and higher thermal conductivity. However, these metals can all be easily bonded with laser welding.
When using lasers to weld objects, aesthetics play a key role. The joints produced by laser welding look exceptionally attractive. The laser welding process allows a very high quality product to be made easily and efficiently.