Novel Low Cost Waterjet Machining of Hard Materials for MDA Applications

New high temperature resistant materials are being developed for the kill vehicles required for missile defense. These materials are typically very hard and difficult or impossible to machine by conventional techniques, thus limiting their use and driving cost and lead time up. Designs are being constrained by manufacturing limitations. These issues will be addressed in the proposed program by further development of waterjet machining techniques that were successfully demonstrated in Phase I. A particularly promising new material is chemical vapor composite silicon carbide (CVC SiC) for use as a seeker mirror and supporting structure. This material requires finish machining after the blank is grown on a mandrel to cut it to shape and reduce unnecessary weight by milling an isogrid pattern on the back surface. The waterjetting techniques to do this will be developed in this program and a test mirror made. Required techniques will be precision zero-taper cutting, controlled-depth milling and piercing. Other techniques which will applications to other supporting structure, such as grooving and turning will also be developed. Other hard ceramic and composite materials will be machined and it is expected that these novel waterjet machining techniques will have widespread use beyond the immediate needs of the Missile Defense Agency to commercial applications such as jet engines and semiconductor manufacturing.