| Abstract | The folded shell projector (FSP) is a compact flextensional sound source being developed for low frequency sonar applications. The FSP radiates sound from within a thin-walled cylindrical shell with superimposed corrugations. The initial prototype of the shell was built by electroforming, followed by NC machining. However, this was an expensive and time-consuming process providing limited choices for the shell material. A novel laser consolidation process for the manufacturing of complex FSP shells was investigated in this study. Advances in the laser consolidation process achieved by IMTI permitted the free-form production of the FSP shell directly from a CAD file delivered over the Internet. The investigation included changing the design of the shell during the program, proving that rapid design evolutions are easily accommodated, as no hard tooling was required. Four shells have been built using IN-625 alloy to validate the process, and assembled into projectors. The laser consolidated (LC) IN-625 shells have a wall thickness of typically 0.8mm. The process parameters have been optimized for high accuracy and surface finish, with wall thickness tolerences of less than 0.02 mm. The calibration results reveal that the LC FSP's show a substantial improvement in performance over the electroformed prototype. |
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