Laser welding
Up to the point that the laser beam contacts the workpiece, all the components that direct it are either transparent, refractive or reflective, absorbing only small amounts of energy from the ultraviolet light. The laser power supply is capable of delivering a "pulse" of light that has accurate and repeatable energy and duration. When the "pulse" of laser energy is focused into a small spot (adjustable anywhere from approximately 0.1 to 2.0 mm in diameter) onto the workpiece, the energy density (energy/area) becomes quite large. The light is absorbed by the (metal) workpiece, causing a "keyhole" effect as the focused beam "drills" into, vaporizes and melts some of the metal. As the pulse ends, the liquefied metal around the "keyhole" flows back in, solidifying and creating a small "spot" weld. The entire process takes only milliseconds. The laser has the ability to fire many pulses per second, and moving the workpiece or optics allows anything from separate "spot" welds to a series of overlapping "spot" welds to create a "seam" weld that can be structural and/or hermetic.
