GREEN LASER WELDING
EWI is using its Miyachi Unitek™ LW2AG, 532nm wavelength, pulsed green laser. The 532nm wavelength produces visible green light. The state-of-the-art laser increases EWI’s capability for non-contact joining of small conductive parts such as gold and copper. EWI will use this laser for a variety of joining applications for its manufacturing customers in the automotive, electronics, medical devices, advanced energy, and other industrial market segments.
Laser welding conductive parts presents a unique challenge due to high reflectivity. The initial reflectivity of laser light from a laser operating at 1064nm for copper is 90%. Therefore, a lot of power is required to overcome the initial reflectivity. As the laser power is increased, the material heats up and the high power needed initially to overcome reflectivity quickly becomes too much and leads to excessive heating and vaporization. Pulse shaping does not provide a solution to inconsistent laser beam absorption. However, when the laser wavelength is cut in half to 532nm (green light) the laser light reflectivity decreases and absorption increases considerably.
This laser allows EWI to create precise welds on small metallic parts without the unwanted effects of flux residue as from brazing or soldering. See examples.