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Flat Wire Deposition Traditional repair techniques for land, sea, and air vehicles in many instances require extensive work involving dismantling of structural components for repair in depot facilities. In many instances, this dismantling procedure is very time consuming and extremely costly. Conventional powder or round wire laser metal deposition repair techniques do not allow for quality in-situ repair of fatigue cracks or corrosion surface damage of large components, especially the components with thin wall structures and when the repair is needed on vertical or overhead surfaces. There is an urgent need at Department of Defense (DoD) repair depots for equipment with in-situ repair capabilities which would dramatically reduce the time to repair or replace critical components, while reducing recurring repair costs, and significantly improving the U.S. military weapons systems support and readiness. With funding through the National Center for Manufacturing Sciences (NCMS) Commercial Technologies Maintenance Activities (CTMA) program, a collaborative project team was assembled for the Flat Wire Deposition Process project. The Flat Wire project was designed in two phases, with a go/no-go decision point following Phase I after which additional funds would be sought for future work. Phase I objectives were to:
The collaborative project partners were:
The team developed, built, and tested for basic functionality a prototype Mobile-PMD™ system for repair and reclaiming damaged large thin wall engine or large curved surface components. A noted complement to the LENS project, this technology is geared towards larger area repair and portability. The initial tests of Phase-I Mobile-PMD™ prototype system prove the feasibility of the system of performing the intended repair/reinforcement operations on large components with suitable mechanical and metallurgical characteristics. A number of technical challenges were overcome during this phase of the project. One of the challenges was to adopt the PMD™ process to operate on truly 3D surfaces, which are prevalent among large aircraft components. The engineering team accomplished the design, construction and tests of the robotic articulated arm with repeatability of ± 0.001 as well as the development of an initial graphic user interface (GUI) software necessary for its operation. During Phase I, only Titanium 6-4 and Titanium 6-4 casting alloys were utilized. The capability of the PMD™ flat wire laser deposition process was demonstrated for repairing of surface damage on large and complex thin wall structure curved surfaces of components as large as 4 to 5 feet in diameter such as a jet engine casing or thin wall titanium alloy exhaust pipe. Phase I demonstrated that this low heat deposition process would provide the repair of large parts with minimal deformation, superior metal grain structure, minimum porosity and potentially improved fatigue life compared to competing processes. The competing processes include MIG/TIG welding and laser powder metal deposition. The advantage of PMD over MIG/TIG welding is the much lower heat input required thus enabling thin wall structures, that heretofore could not be processed, to be repaired. The advantage of PMD over the powder metal deposition processes is that it is not constrained to be in a controlled atmosphere cabinet. Thus, much larger parts can be repaired. Program Manager: Mike Gnam, (734) 995-4971, mikeg@ncms.org
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