The influence of the workpiece illumination proportion in annular laser beam wire deposition process

The paper provides a description of an annular laser beam based direct wire deposition head, which can be used to perform controllable, simultaneous, and symmetrical heating of both the workpiece surface and the axially fed wire. In order to characterize the proportion of energy delivered to the workpiece and fed wire, respectively, a new process parameter, referred to as the workpiece illumination proportion, has been introduced, which is defined as the percentage of the annular laser beam power incident on the workpiece surface. The influence of this newly defined illumination parameter on the process outcome was characterized, based on single-layer deposition experiments using a 0.6 mm diameter nickel wire which was fed onto a stainless steel workpiece. The results show that the geometry of the deposited layer is influenced, as well as by the conventional process parameters, also by the newly introduced workpiece illumination parameter, which also affects the process stability and its robustness.