Functional design framework for innovative design thinking in product development

Functional design means the process of formulating a unique design problem by mapping a set of customer needs to a set of functional requirements. In the context of product development, functional design is one of the most challenging but rewarding design activities. On the one hand, designers must extract useful information from a large amount of diversified, unstructured, and even inconsistent customer voices. On the other hand, designers must formulate a set of functional requirements that are inherently intangible, solution-neutral, and arguably subjective. Functional design exerts great impacts on the formation of innovative design thinking. It is especially difficult for novice designers who are naturally inclined to rapidly dive into the solution space with little exploration of the problem space. This paper presents a systematic functional design framework to guide novice designers, through a step-bystep process, to sequentially investigate the customer domain, explore the functional domain, and manage design couplings between customer needs and functional requirements. A collection of existing design methods is incorporated, in an adaptive manner, into the framework to facilitate the execution of each step. To date, the proposed framework has been iteratively taught, practiced, and refined based on two engineering design courses since 2013. (c) 2020 CIRP.