Mitsubishi Electric (Tokyo, Japan) and its affiliate company Tada Electric are jointly developing a new fiber laser welding technology that cuts flying molten metal (spatter) by 95% or more (when compared with conventional technology during welding using hot-rolled material).
Conventional spatter levels can lower the quality and speed of fiber laser welding, so the new low-spatter technology raises the welding quality and productivity of high-power fiber-laser welding for industrial applications such as steel processing, automobile production, and electrical equipment installations. The new technology is expected to be incorporated in laser welding machines that will appear in 2019.
In laser welding, a deep penetration hole and a molten metal pool are formed in the area irradiated with the laser beam. Laser power can be raised for deeper penetration, but this can generate excessive spatter. So the two companies, after studying molten pools under a variety of welding conditions and conducting more than 10,000 experiments with a high-speed camera, discovered that spatter could be greatly suppressed by irradiating a low-power laser beam around the high-power beam. Later, using a newly developed optical beam-forming system installed at the output end of the optical fiber, a low-power laser was irradiated simultaneously around a high-power laser focused on the same point. Testing with a 10 kW high-power fiber laser confirmed that spatter could be reduced by more than 95% compared with a conventional system working at the same welding speed.
In conventional fiber laser welding, spatter increases remarkably at certain welding speeds, requiring the speed to be lowered to ensure welding quality. However, using the new technology when raising the welding speed increases spatter only minimally, allowing for the full benefits of the laser's power to be used. In a test using 4.5-mm-thick SPHC (hot-rolled steel), the technology's welding speed was double that of a conventional welding process.
For more information, please visit www.mitsubishielectric.com.