Experimental laser welding efficiency

In order to model the laser beam welding process either analytically or by numerical techniques, it is necessary to know the efficiency of the process. Efficiencies have various meanings depending on their application and utilization. But in each case, the efficiency is the ratio of the energy absorbed to the total energy applied the work piece. Measurement of the total energy at the work piece is relatively simple and can be done accurately with a water calorimeter and a few precautions. Measurement of the energy absorbed can be made by a variety of techniques, such as measuring the temperature of the weldment by infrared cameras, measuring the energy of the laser beam below the work piece, measuring the volume of the fusion zone and calculating the energy required to melt that volume, preplacing thermocouples in the heat-affected zone and measuring their temperature, or by other techniques. In this experimental study, the temperature rise in preplaced thermocouple was chosen as the appropriate technique...