Laser Brazing of Aluminum Alloys
| •Process Description
As the demand for more efficient vehicles increase, the automotive industry is transitioning from galvanized high strength steel body panels to aluminum alloy body panels. The coach-peel joint is a visible seam between two panels that needs to possess high surface quality. Galvanized steel lent itself to the laser brazing process because the zinc layer on the surface was vaporized during the joining process; allowing for a clean, oxide free surface in which brazing is done with exceptionally high surface quality. Aluminum, however, has an ever present oxide layer on the surface. This oxide layer is good in that it prevents further corrosion, but it is detrimental to the brazing process. Flux can be used to chemically remove the oxide layer for brazing, but this require application of the flux, and removal of the residual post joining. This work aims to develop a flux-free joining technique for aluminum panels in a coach-peel configuration that possesses sufficient strength and high surface quality.
| •CLAM Capabilities
The joining process is conducted using a 4 kW continuous wave fiber laser that is mounted to a 6-axis robotic arm. Filler material is added into the groove of the joint by a precision wire feeding system. Experimental investigation is being conducted to determine the effects of processing parameters on the surface quality of the joint as well as the strength of the joint. A beam splitter is being utilized in an attempt to improve the process stability and results. Thermal modeling of the process is being conducted to provide a better understanding of the process and to predict the temperature distribution during the process so that the laser power can be optimized during the process.
| Experimental setup of laser joining coach-peel samples
Cross-Section of Joined Samples compared with Preliminary Simulation Results