IMPROVED AIRFRAME MANUFACTURING TECHNOLOGY

The objective of the Improved Airframe Manufacturing Technology (IAMT) program is to select and demonstrate technologies that will reduce the cost of building complex primary airframe structural composites assemblies. The IAMT program takes advantage of advanced manufacturing processes and tooling concepts that promise to reduce the cost of manufacturing. Incorporation of such improvements must have only a moderate design impact with minimum risk. The advanced technology selected for the IAMT program is the resin transfer molding process. This method was selected based on significant advancements made to the conventional RTM process, such as innovations in elastomeric tooling technology, advanced resin systems, automated preform development, and automated ply cutting and kitting. The potential for automation, particularly in the area of preform manufacturing and assembly, and the elimination of fasteners and post cure machining make the RTM process attractive for large complex airframe structures. Other advantages associated with RTM, such as elimination of expensive prepreg with limited shelf life, along with costly autoclaves to process them, are realized with the RTM program. In addition, reduction in variability made possible by precision tooling and process controls will result in consistent high quality structures. Proprietary tooling innovations are being implemented on this program which enables the fabrication of complex internal part geometry without the traditional lock-in problems associated with match metal tooling. The tooling concept also provides maximum fiber compaction during the molding process in a way that conventional matched metal RTM tooling cannot provide. In addition, the matrix material used in this program, 3M Scotch ply PR500, has mechanical properties comparable to toughened epoxy prepreg resin systems. Therefore, the resulting composite has mechanical properties and fiber volumes comparable to autoclave cured laminates.