Laser welding instruments are devices which have the capability to concentrate laser photons into a high-energy beam, which produces massive heat when it comes in contact with other materials.  When a thin, high powered laser beam is focussed at the juncture of two metal pieces placed over a heat resistant substrate, the resultant heat melts the metals, allowing one to mould and fuse the metal pieces into any desired shape. After the laser source is shut down, the temperature drops and solidification of liquid metals yield a single welded block of metal. Since the use of laser generates heat in a tiny area only, its permits extreme precision in welding and shaping work.

The laser beams used for welding can be charged as a continuous linear stream of photons or as a series of pulses, each lasting for a few milliseconds. While the continuous streams are utilized in making deep welds, the pulsating photons find application in cutting metals to minute pieces. In modern times, workers safety is the prime concern in industries, most welding setups make use of robotic arms to shoot the laser beam through target metals, thereby jointing them into one. Also, there are other setups where remote consoles are utilized in steering the movement of the laser beam.

There are two types of laser welding- Laser Conduction Welding and Laser Penetration Welding.