Technology suitable for both serial and small quantity production

Laser micro welding is a process to realize a precise weld joints with small distortion on small and tiny metal or plastic parts in the range of micrometers and millimeters size. The principle of laser welding is based on the heating and melting of the material caused by absorption of laser high-power radiation. For laser microwelding two types of laser sources are used: cw laser for seam welding and pulsed laser with pulse duration about 1-10 ms for single spot or spot seam welding. As laser source for welding solid-state laser (as a rule Nd:YAG laser) usually are used.

As laser welding is non-contact, no welding tolls are required and it is possible to weld versatile (and also delicate) joint configuration without contamination of the components. Very good energy focusability and controllability of the laser beam enables welds in the sub-micro range with very small heat-affected zone and heat distortion. Because of the very short welding time (few milliseconds for pulsed spot welding) laser welding is very attractive for series production. An essential requirement for good a weld quality in laser welding, as well as in other micro welding processes, is a small or no gap between joining partners.

Laser soldering, as well as other soldering processes, use filler material (solder), which in liquid state wet the materials to be joined and provide mechanically and electrically stable connections if it is solidificated. The energy for melting of solder is applied by mean of laser beam. There are three different laser soldering processes: single spot, laser line and laser spot line (simultaneous and quasi-simultanious) soldering. The typical laser source for soldering are solid state lasers and particularly diode lasers.

Because the laser energy can be focused and portioned out very exactly, the laser is especially used for soldering of the temperature-sensitive assemblies and boards. Also it is used for joining of assemblies with high thermal capacity that could be not conventionally soldered in the reflow process. Other large application field for laser soldering is the selective rework: soldering out of defective assemblies and soldering in of new components.