Certification is a big hurdle for adoption of additive manufacturing (AM) on structural elements in the aerospace industry for production. Structural elements manufactured for normal or transport category airplanes and rotorcrafts, for example, must be in full compliance with multiple CFR/CS regulations. A systematic certification framework is presented using a building block approach where design, analysis and manufacturing are incrementally developed and validated from a coupon level all the way to a full-scale assembly level on flight test aircrafts. Analysis validation by test is performed at every step to allow a certification by analysis approach, which is immensely scalable and cost effective for introducing new technologies such as AM into production. Variability is controlled through material and process specifications for powder feedstock, feedstock reuse and handling, fusion process and post processing steps. Design allowables are statistically derived from testing of independently fabricated specimens where materials are purchased and specimens fabricated using the same approved specifications. The specimen testing is reflective of variability arising from using multiple powder sources, machines, machine operators, build orientations, build thicknesses, operating temperatures and surface finishes, thus covering the design space for a wide variety of AM applications. An example of how this approach is currently being applied to develop and certify one of the largest structural component manufactured developed at Collins Aerospace using metal powder bed fusion process — metallic cascades on jet engine thrust reversers — is presented.
- Better identify and define the business case for pursuing and investing in additive manufacturing technologies.
- Define the certification and qualification requirements and roadmap for pursuing additive manufacturing on structural applications in the aerospace industry.
- Better understand the various considerations and hurdles faced in a production environment, and the conflict between need for a frozen versus flexible process.