Laser welding, in the recent past, was used only for the purposes, which could not be done with the conventional methods of welding. However, the scenario has considerably changed, and laser welding is one of the major techniques used in the metalworking industries, as the concentrated energy of laser results in a better quality of weld.
The operation of laser welding is economical and efficient due to its versatility and can be used in place of any other welding technique. It is also advantageous over other conventional processes, as its equipment can be used for some secondary purposes also, such as cutting, drilling, sealing, and scribing, etc. Clearly, the laser welding equipments and the technique itself, are multifunctional in their nature!
It is also true that a few manufacturing experts do not prefer to use laser welding, for, the operation and the capability is not so familiar among the workforce. It involves a higher initial cost and trained workers that can operate on the equipment and machines.
As welding is based on the principle that metal has to be brought to its molten state; and then, solidifying it under pressure, and creating a weld joint, the laser welding technique uses light energy for the purpose of heating metal pieces. The light is absorbed by the metals and heat is produced helping to attain molten state.
In common, two types of laser beams are being used for welding operation--CO2 and Nd:YAG. However, both of these operate in the infrared region of the electromagnetic radiation spectrum, which is invisible to the human eye.
In laser welding, a keyhole is created with laser beam, and the liquid steel solidifies behind the traversing beam, leaving a very narrow weld, approximately 1 mm wide; however, the surrounding material is not distorted. There is no need for finishing or reworking of the welding joint, which reduces the cost involved, potentially!
Below are some facts that are important to understand the overall functioning of laser welding process:
· Thermal diffusivity is inversely proportional to the ability of material to conduct heat—lower the diffusivity, the more the heat remains in the vicinity of the laser beam spot.
· In case of metals having lower boiling points, plasma generation could occur, as large amount of metal vapors are produced, which could absorb the energy and block the laser beam.
· Although the laser weldability does not depend upon the melting point, still, it must be reached during initial absorption. That is why metals having lower melting points are easy to operate on than those ones having higher melting points.
Safety in laser welding process is one of the major concerns for the manufacturers and for the scientists also. Laser welding process involves emission of concentrated light energy infrared beams, which are invisible in general. So the operator needs to be much careful while performing the task, as these could focus on to the skin or eyes, and are harmful for human beings. The person working on laser welding equipment should follow the safety norms implicitly and diligently!