This requires lower intensity hence larger spot sizes but higher average power. Lasers can produce a continuous seam either by overlapping individual weld spots or by a continuous melting process. Although these weld seams are typically wider than laser cuts, they are still very much narrower than can be produced by conventional flame or electric arc welding techniques. The total heat affected zone is therefore much lower. Laser soldering is increasing in popularity as the soldering of heavily populated PCB's and PWB's becomes increasingly difficult.
Lasers can solder smaller joints than are possible using conventional manual techniques.
Both CO 2 and diode lasers have been used. Laser brazing is a relatively new technique that is not widely used as yet. Melting of braze in this case is usually achieved indirectly by conduction through one of the surfaces to be joined. Large spot sizes are therefore employed.