New Infrared Technologies (NIT), in collaboration with the AIMEN Technology Centre, has developed the I3LASWELD system for the inline quality control of laser welding processes, capable of detecting defects in weld seams in real time and identifying defective parts.
The I3LASWELD system (Inline Infrared Imaging Laser Welding QA) is based on a high speed infrared camera (1 kHz) manufactured by NIT, opto-mechanically coupled to the laser optics, which continuously monitors the geometry of the melt-pool. These infrared images of the melt-pool, acquired coaxially, are processed in real time using powerful algorithms based on neural networks, which provide information about the areas where the defects are concentrated and thus enable an evaluation of final quality (OK / NOK).
The I3LASWELD system is compatible with both fixed and remote welding laser optics, and can be trained to detect multiple defects in different configurations, process types (transparency, butt or edge), sheet materials and thicknesses. As training is based on images of real processes, in which the defects to be detected have been forced in a production scenario, I3LASWELD provides very high defect detection rates with a success rate of more than 99%. Some examples of defects that I3LASWELD is able to detect very accurately are: lack of penetration, lack of fusion (false friend), excessive throat depth and absence of bead (discontinuities, pores, holes), among others.
I3LASWELD has been successfully validated in a collaborative project with VOLVO, in which quality control of transparency welds between steel sheets (0.75 mm + 0.70 mm) was carried out to ensure that the process met the required standards regarding both depth of the weld throat and internal width of the joint.
Currently, NIT and AIMEN are implementing the I3LASWELD system in a GESTAMP production cell, at its Abrera plant, to detect defects in welds on-the-fly using a remote welding optical scanner, aiming to control the quality of more than 10,000 weld beads per production shift. The interconnection of I3LASWELD with the production quality control system implemented in the process cell will enable immediate performance metrics to be obtained, providing very accurate and valuable information to production engineers, in real time.