Machining Parameters for Direct Digital Manufacturing (DDM) of Aerospace Components

ABSTRACT: Direct Digital Manufacturing (DDM) of aircraft metallic components is an emerging and innovative manufacturing process, which can create or repair metallic parts directly from powder metal. DDM promises cost, time and efficiency benefits over traditional machining processes (in which material is removed using cutting tools) in the area of low production volumes, processes involving constant design iterations and manufacturing parts that have relatively complex geometric shapes. For conventional materials, machining processes and material irregularities they cause are well known and any potential failure points or induced stress points that could result in failures have corrective actions to take (e.g. Heat treat). But the newer technologies of additive metal fabrication materials are unknown. We are proposing a research of the required machining processes (Turning, milling, grinding) for final machining of DDM parts and the standardization of these processes to eliminate stress build up or failure points. Phase I research will be restricted to demonstrate the viability of the DDM process by developing machining parameters that will not alter the DDM part microstructures and define metrics for measuring the effectiveness of implementation of the machining parameters and proposed standards, the methodology used, and concept analytical tools produced. BENEFIT: Worldwide market for titanium alone is estimated at $225bn for 2008-2009. Aerospace, being the single largest user in this market, constitutes 56% of the market segment. 16% is for military aerospace market, while commercial aerospace market is the rest 40%. Non-aerospace market, such as medical devices, chemical, automotive, sports industry together constitutes the rest 44% of the titanium market. Last year alone, 5000MTon of titanium has been used in USA in aerospace applications and 90% of this is structural application. Largest single use of titanium is in the aircraft gas turbine engine. In the most modern jet engines, titanium-based alloy parts make up 20% to 30% of the dry weight, primarily in the compressor. The potential market for this technology, specific to metallic aircraft parts for defense application is estimated to be more than $100 millions annually within Northrop Grummen alone, and more than $500 millions industry-wide. Since DMD, a leading DDM process, integrated with proposed machining parameters, achieving improved dimensional accuracy and material integrity described in this proposal, is enabling and certified, it is expected that fundamentally new design concepts and applications could expand the market well beyond $1 billion. To access this market opportunity, POM will offer application and engineering services to introduce new customers to a state-of-the art DMD technology, and to optimize specific processes. Customers will have the option to have POM directly manufacture production parts, or alternatively, to purchase DMD systems.