Case Study: Canard
Process: Metal injection molding
Materials: Stainless steel
End Use and Function
This stainless steel powder metallurgy (PM) component is used on the Talon, an add-on guidance and control package that transforms a legacy 70-mm (2.75-inch) Hydra-70 unguided rocket into a low-cost, precision-guided weapon. Three canards on each Talon act as the primary flight control surfaces. While the metal injection molding (MIM) tooling was fairly straightforward, sintering demanded specially engineered and fabricated ceramic setters in order to maintain the extremely accurate profile tolerances of the airfoil surfaces without secondary operations, which is very difficult to achieve during shrinkage from the green to sintered component.
Machining the attachment/pivot lug detail on the proximal end, and the latching notch on the distal end are the secondary operations performed, followed by solution treatment and aging, and finally bead blasting. Several milestones had to be achieved during this qualification process, especially the fundamental testing and analysis of the stress corrosion properties of the MIM material, which involved the integral use of 3D CT scanning during development.
This PM component is highly challenging in its geometric complexity without the need for extensive secondary processes as well as the high physical and dynamic properties required for the application. It demonstrates to the defense industry that MIM produces structural parts that meet all mission requirements at significantly reduced costs. The conversion of the canard from one fully machined from wrought to the MIM design, at a cost savings of more than 65%, represents a successful collaboration to qualify a highly critical structural application by two major aerospace organizations.