Keys to Successfully Implementing Design for Manufacturing and Assembly (DFMA) Techniques to an Existing Production Program

Abstract

Frequently, new design efforts have successfully used DFMA techniques in order to yield designs that are simpler and faster to assemble, easier to maintain, and less costly than designs that utilized the previous philosophy of several small parts being mechanically fastened together. However, a substantial difference exists between using DFMA on a new program, such as the F/A-18E/F Super Hornet or the Joint Strike Fighter, and using DFMA on an existing production program such as the F-15 Eagle or the C-17 Globemaster III . Generally, design efforts on a new program would be funded under that particular program's development costs. However, for an existing program where the program life is limited, it becomes more challenging to implement DFMA techniques to new redesigns since the return on investment (ROI) and break-even point are directly proportional to the expected life cycle savings and implementation costs. This paper will explore ways to successfully implement DFMA and pitfalls to avoid when planning a redesign activity for an existing production program. The United States Air Force (USAF) C-17 Globemaster III is designed and built by the Boeing Company. The C-17 has been a hugely successful transport aircraft, as evidenced by being the winner of the prestigious Collier Trophy and having an exemplary service record, including combat experience during the Bosnian Conflict. In 1994, the USAF awarded McDonnell Douglas Corporation a contract extending C-17 production through 120 aircraft. The C-17 program office in Long Beach, along with subcontractors who build major C-17 subassemblies, then undertook several initiatives aimed at reducing the cost of the airplane. Four successful C-17 redesigns will be examined that were aimed primarily at reducing cost and span time: the cargo ramp floor monolithic machining project, the cargo ramp vent door support structure casting, the low cost crew door redesign, and the main landing gear pod-to-fuselage attachment redesign.