Deep penetration welding requires extremely high power densities of about 1 megawatt per square centimeter. In this process, the laser beam not only melts the metal, but also produces vapor. The dissipating vapor exerts pressure on the molten metal and partially displaces it. The material, meanwhile, continues to melt.
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Determining weld depth during laser welding | Industrial Laser Solutions
The company was awarded second place for their "Measurement of welding depth and topology in laser material processing using low coherence interferometry" development. The use of laser light as a material processing tool has tightened the requirements for quality assurance. Laser welding in particular is governed by strict quality specifications for qualifying the robustness and durability of welding seams. One of the key parameters is the welding depth, which indicates the depth to which the material is fused during the joining process.
Determining weld depth during laser welding
Penetration in laser welding refers to the depth of fusion. It is the distance that fusion extends into the base metal or previous pass from the surface melted during welding. All welding requires the pieces of metal and filler metal to have complete fusion in order to have proper weld strength. Whether it was a deep or shallow penetration, the important thing is you have joined the metals together in one piece. However, there are circumstances where deeper penetration in laser welding is more beneficial.
A fiber laser head welds with real-time weld depth monitoring using inline coherent imaging, or ICI. Many variables affect the quality of a laser weld. The laser power needs to remain stable and the optics must remain as clean as possible to avoid problems with the beam such as focus shift, which can change the spot size and, in turn, affect the weld quality. These all are optical issues.