Industrial laser testing and characterization at NIST
Directly measuring laser power, and connecting power to weld properties, are among the unique capabilities of this lab developing a better understanding of laser welding.
The National Institute of Standards and Technology (NIST) facilities in Boulder, CO are home to the Laser Welding Program in NIST's Physical Measurement Laboratory.
Laser welding is more energy efficient than conventional welding, says PML physicist and laser applications project leader Paul Williams. Conventional welding typically uses an arc of electricity to heat and fuse materials. In contrast, a multi-kilowatt laser beam can heat a smaller area of the metals being joined, creating a smaller, smoother seam than a conventional weld, on the order of millimeters rather than centimeters. Williams and laser safety officer Josh Hadler are featured in this SPIE video recorded in the lab at NIST.
Their facility features a welding booth -- an enclosed space for the welds to take place -- as well as lasers capable of producing a beam up to 10 kW. (A 10 kW laser can cut 1 cm of stainless steel.) A set of spectroscopy instruments will give them a measurement of the atoms leaving the metal during a weld, which will help them to understand local metal composition.
By measuring radiation pressure, Williams and colleagues have created a system that gives them an absolute reading of their laser's power in real time. This is a first; previously, only relative measurements in real time were possible. Early results include real-time power measurements during the weld process, which could profoundly change how laser welding is done. The team also has preliminary data connecting laser power to weld properties.