Increased efficiency during laser buildup welding by combining energy sources (SPRAYNERGY)
Excellent precision, highest mechanical strength and tailored properties of surface coatings and generated 3D structures: these characteristics led to the industrial breakthrough of laser buildup welding processes in series manufacturing. However, low deposition rates and limited energy efficiency set barriers for the technology – in particular for simply shaped parts. Exam ples include long hydraulic cylinders in offshore applications, oil production and mining tools as well as large screwconveyors, which require high strength surfaces. In terms of the coating properties required for these applications, there are no alternatives to laser buildup welding. However, the comparatively high coating costs have been limiting the use of this technology for these applications.
Laser buildup welding, just like any buildup welding process, suffers from energy losses. These are principally connected to the welding process and affect its efficiency. Heat conduction into the base material assumes a key role. On the one hand this cooling process enables the solidification of the laserinduced melt. It also represents the major loss component of the expensively generated and precisely applied laser energy. Up to 90 % of the absorbed energy drains into the workpiece. The fast heat conduction in combination with the laser beam tool leads to especially high cooling rates and spatial temperature gradients, which may become critical for crack prone coating materials.