US Patent 9217331 Impeller balancing using additive process

A number of variations may include a method of balancing a rotor assembly and a balanced rotor assembly which may involve additive material applied to the rotor assembly. One or more of the following options may be employed: adding a mass to an impeller hub between two adjacent vanes; adding a mass to an impeller back wall; adding a mass to back wall scallops, and adding a mass to an impeller nose. Material removal may be used in combination with material addition.