Evaluation of design process alternatives using signal flow graphs

Abstract

The introduction of new design activities into an established product development process may involve more work in the initial stages of development, yet this extra effort may reduce the need for more expensive and time-consuming redesign activities later in the project. Wehave studied a case where more intensive use of computational simulations in the early design phase means that fewer hardware tests are needed because the designs can be analytically evaluated in advance of physical testing. Total development lead time and cost can thus be significantly reduced. This paper addresses how to evaluate alternative design strategies and methods with respect to their impact on the development process time. This is achieved by analysing the design process using signal flow graphs. The technique has been applied to jet engine component development projects at Volvo Aero Corporation in Sweden. We have found that evaluating alternative processes using signal flow graphs not only is helpful to assess the effect of introduction of new or improved design activities on the development process, but also is a means to facilitate the discussion of process improvement alternatives and trade-offs for an organization.