Product Code: ICAL06_1206

Laser Consolidation of Net-Shape Shells for Flextensional Sonar Projectors
Authors:
Lijue Xue, National Research Council Canada; London Ontario Canada
Chris Purcell, Defence Research and Development Canada- Atlantic; Dartmouth NS Canada
Presented at ICALEO 2006

Laser consolidation (LC) is a computer-aided manufacturing process that builds a functional net-shape part directly from a CAD model, without the use of moulds or dies. The folded shell projector (FSP) is a compact flextensional underwater sound projector developed by DRDC-Atlantic for low frequency sonar applications. The radiating surface of the FSP is a thin-walled shell of complex shape that challenges conventional manufacturing technologies. In this study, several versions of the FSP were designed using DRDC-Atlantic's MAVART finite element code. NRC-IMTI refined the laser consolidation process and successfully manufactured the complex shells from IN-625 and Ti-6Al-4V alloys. The laser consolidated net-shape shells are metallurgically sound and exhibit excellent surface finish, dimensional accuracy and mechanical properties. Field tests of FSP prototypes demonstrated that the shells met their design goals of resonant frequency and source level. Other manufacturing methods for building the shells (hydro-forming and Ni vapor deposition) were also explored. However, at the moment, the laser consolidation process is the only manufacturing technology capable of making the FSP shell to the required tolerances.