Abstract
Product development involves many trade-offs between upstream objectives (e.g., customer needs) and downstream constraints (e.g., modularity, manufacturability, etc.) Conceptual design, when design concepts are generated and improved, is the most important product development stage when these tradeoffs are made. However, when designers try to improve a known design concept of a current product during product development, it is often difficult for them to be both creative (i.e., meeting new objectives) and practical (i.e., incorporating existing constraints) at the same time. This paper presents a method that models known design concepts and manages their functional couplings for designers to achieve these difficult balances systematically during concept improvement. The modeling involves three steps. The first is to represent the known design concept as a dual-hierarchy by decomposing it into sub-concepts and identifying their functional requirements. The second is to find “functional schematics,” defined as a design matrix with minimal complexity, to manage functional couplings of the sub-concepts. The third is to build the executable modules based on the functional schematics. The model help designers achieve the most desirable level of upstream-downstream balance. A coffeemaker example is included to show how such a model of design concept is created and its design coupling modules are managed. The result also suggests that this approach can be used to create a “product family” from the base (or an existing) product to meet continually changing market demands.
