Ball end milling of titanium TIG weld material and the effect of SiC addition - process forces and shape deviations

An increasing amount of blade integrated disks (Blisks) is used in turbine engines. These integrally milled components offer benefits regarding to their performance-to-weight ratio. However, in case of failure, partial replacement is not possible. The Blisk has to be replaced entirely or repaired using re-generative processes for increased sustainability. Usually, a welding process is applied for patch repair or to build up a worn tip. Afterwards, a re-contouring process such as milling is needed to restore the original shape. To determine the influence of the welding process on the process forces during subsequent ball end milling, TIG welds have been re-contoured. Moreover, to achieve grain refinement in the fusion zone and enhanced mechanical properties, SiC was added to the weld pool. Process forces during milling as well as workpiece deflections were measured. It is shown, that the welding process has a serious impact on forces and needs to be considered for a precise process planning.