The main applications of Hundred-watt fiber delivered direct diode lasers include laser soldering and plastic laser welding. Laser soldering provides flexible solution for unleaded electronic soldering through accurate position, temperature control. Laser soldering possesses the characteristics of Non-contact soldering, heating speed, small heat affected zone, it would be more suitable for unleaded processing by fast heating and small heat influence. At the laser beam-transmission welding plastic, this technique requires one part to be transmissive to a laser beam and the other part to be absorptive to the beam or a coating at the interface to be absorptive to the beam. The two parts are put under pressure while the laser beam moves along the joining line.