M. Walluk, A. Luccitti, B. Hilton, B. Baker, K. DePalma, K. Sisak, P. Martin
Rochester Institute of Technology,
Keywords: additive manufacturing for repair, framework, additive friction stir deposition
Summary:Maintenance and sustainment of high value assets, such as vehicles, often relies on replacing damaged components rather than repairing them. In the case of components that no longer have a replacement option, additive manufacturing (AM) technologies are being considered to build these components from scratch through use of 3D printers. For some components this may be feasible, however, replacement using current 3D printing technologies is not always possible due to limited material options and performance considerations. Furthermore, replacement with new or printed components can be more costly than repairing the existing assets. Due to these challenges, the option to repair damaged components using maturing AM Repair technologies is enticing to many industry and government practitioners. Within the engineering community there is a knowledge gap in how to efficiently evaluate potential AM Repair approaches against the original equipment part performance requirements, especially when original design information is unavailable. The performance and durability of repaired components must meet the requirements of the application, which is highly dependent on the AM technology and material combination used for the repair. Additionally, each damaged component must be evaluated to understand the particular condition that resulted in removal from service. Adoption of AM Repair processes for the damaged component is currently limited by complexities associated with material properties and the need for a comprehensive, systemic solution for repair. One approach to this problem is the definition of AM Repair solutions based on their technological and functional capabilities. The present work focuses on creation of a framework to determine if components are suitable candidates for additive repair and, if so, recommend an AM repair process and material combination that is best suited for the functions of the part. This task requires an understanding of both the initial performance requirements of the part and the functional failures that caused the need for repair. The decision tool, which recommends an appropriate additive technology, must draw on a database of mechanical properties from a variety of process-material combinations. For an example, this presentation highlights one of the AM repair technologies being investigated, additive friction stir deposition (AFSD), that adds material to a substrate through a thermo-mechanical process. Specifically, AFSD for the deposition of aluminum 6061-T6 to repair similar 6061 plate was used as one of the AM Repair options in a case study to demonstrate the framework. Material testing was conducted to populate the as-deposited material properties along with the original substrate properties to be used in the evaluation.