First introduced for sheet metal applications, laser welding today is used across all industries and a wide range of steels and alloys. The importance of the technology is driven by the requirements to manufacture leaner, reduce material cost and join dissimilar materials amongst many others.
The advantages of laser beam welding:
- Very little heat distortion
- Extremely precise and high welding speeds
- Excellent weld seam quality and a narrow weld
- Typically no finish machining process required after laser welding
- Many hard to weld materials and material combinations can be joined with laser welding.
As applications have grown to cover a wide range from small medical components to large shipbuilding parts, so have the different laser welding techniques.
Keyhole welding is producing the laser typical narrow welds within a penetration range of a few thousands of an inch to an inch and more in a single pass. The exceptional weld quality is used for hermetic seal areas, highly dynamic loaded parts and components, heat sensitive assemblies and many more. Depending on the individual material or joint fit-up requirements the process is run with laser alone or laser and filler wire.
Heat Conduction Welding:
Heat conduction welding is generating laser welds that look similar to arc welds but with much less heat input and distortion and exceptional surface quality. This process is used for assemblies that have penetration requirements of less than approximately .120” -.0160”, less than ideal fit-up, and superior weld surface quality. The process is run with laser only or laser and filler wire. This process is also used for build-up welding or machined groove welding where low heat input is essential.
Pulsed Laser Welding:
Pulsed laser welding is generally used for smaller components. A series of high frequency, small duration pulses is essentially creating a solid band of overlapping spot welds. The process is also used for very heat sensitive applications. The welding process can operate with just the laser or laser and filler wire.
In hybrid welding a laser source is combined with another energy source, such as an induction generator or arc welding source to combine the advantages of both technologies. Hybrid applications are found where increased weld penetration is needed, weld fit-up is poor or the welded materials require a slower cooling cycle to avoid phase formations and cracking.