Principles from Toyota’sset-based Concurrent Engineering Process

(SBCE) by reasoning, developing, and communicating about sets of solutions in parallel and relatively independently (see Figure 1). As the design progresses, they gradually narrow their respective sets of solutions based on additional information from development, testing, the customer, and other participants’ sets. As they narrow, they commit to staying within the set(s), barring extreme circumstances, so that others can rely on their communication. This paradigm results in development practices that at first glance appear inefficient and wasteful—for example, developing large numbers of alternative design prototypes—but are logical when viewed in context. Since the initial study we have continued interviewing Toyota managers and engineers. Further study verified that the practices we learned about were not aberrations. We also learned about other practices that contribute to design process efficiency and create a environment conducive to set-based design. In addition to the Toyota study, we have conducted a series of workshops where US engineering teams, after an introduction to the ideas of SBCE and Toyota’s practices, apply them in the design and manufacture of a mechanical toy.