Advances in Manufacturing Superplastically Formed and Diffusion Bonded Components

摘要

This paper will discuss some of the advances that have been made at Boeing Commercial Airplanes to manufacture production and research Superplastically Formed and Diffusion Bonded (SPF/DB) structure. Even though SPF/DB has been in production for over twenty years, challenges have been encountered that need solutions before the process can see wide spread acceptance. Airplane engineers, designers and stress analysts, need to be assured that the process will yield quality hardware that meets structural requirements. However, the engineers must have requirements that are realistic. For example, if there are areas that can tolerate non-bonds of a certain size and still be structurally acceptable, then the drawing should be zoned accordingly. One of the main concerns is the diffusion bond quality that is achieved and how can this be determined without destructively evaluating each part. Also of interest is the weight of the part since titanium is being used for SPF/DB and the structure does not always need this material to meet requirements. A key element of the weight issue is the thickness needed to meet structural requirements. Fortunately, with Finite Element Modeling, the proposed SPF/DB geometry can be modeled and the thicknesses predicted. An estimated weight can now be determined and a decision made whether steps need to be taken to reduce the weight in order to be competitive with other fabrication technologies. After SPF/DB has been selected as the manufacturing method of choice, the hardware needs to be fabricated so that quality is achieved throughout the entire process and the engineering requirements are met.