Papers by Keyword: Superplastic Blow Forming

Abstract: Institute of Space and Astronautical Science (ISAS/JAXA) in collaboration with Mitsubishi Heavy Industries (MHI) has developed fuel and gas tanks for reaction control system and orbital control system of satellites; A tank is fabricated through welding of two thin, hemi-spherical or conical parts, which are fabricated by superplastic blow forming. Mass-productivity is not an important factor but the forming precision and flexibiliry in the process are important for this application. ISAS and MHI, therefore, developed a new blow-forming technique, which has high flexibility in terms of tank size because it requires a furnace but not a hot-press machine. Some typical propulsion tanks fabricated through this process are presented.

Abstract: Superplastic blow forming with diffusion bonded sheet is an effective forming technology for the production of multi-cell structures which should have light weight and high stiffness for aerospace purpose. In the current study, finite element analysis on superplastic blow forming process has been carried out in order to improve the forming process when manufacturing axi-symmetric multi-cell structures using diffusion bonded Ti-6Al-4V multi-sheets. The simulation focused on the reduction of forming time and obtaining finally required shape throughout investigating the deformation mode of sheet according to the forming conditions, which are diffusion bonding pattern and die geometry. To reduce forming time, a preforming die was required, and to obtain the final shape the bonding pattern should be also modified within allowable geometrical margin, so that the sheet is easy to deform. Moreover, an intermediate simulation result, which was forming pressure profile, was employed in real forming test to check if the prediction was reasonably on progress. In the future, a study on the thickness ratio between each sheet should be followed to obtain optimum process parameters.