Abstract—The use of function has been recognized as an important part of the design process over last two decades, especially at the conceptual design stage, due to its critical role in determining the final product’s functionality. Although there are now some general methodologies dealing with functions or reasoning about functions, virtually no commercial CAD system can support conceptual design process due to their focus on geometrical modeling but not functional modeling. This paper presents a functional modeling approach to guide conceptual die design through functional reasoning steps including functional decomposition, functional supportive synthesis and function-structure mapping. The formed functional model provides a good basis to generate various die structures at the conceptual design stage, because function is a higher level of abstraction than structure, and helps to capture the designer’s intent. The functional modeling process has been implemented in a computerized design environment to expedite the conceptual die design process.70105

Index Words—Conceptual design; Die structure design; Functional model; Functional modeling; Functional reasoning

1. INTRODUCTION

In engineering design, all products and artifacts have some intended reason behind their existence: the product or artifact functions [1]. In other words, engineering design process should be guided by functions. A crucial early stage in the design process is the conceptual design stage, during which an initial design solution to the design problem is devised to fulfill the required functions [2]. Functional design [3] has become a new perspective towards the research of conceptual design activity, and its objective is to provide computer tools to link design functions with the structural (physical) embodiments used to realize the functions. Generally designers agree that function is the most important concept in determining a product’s basic characteristics, because products with problems in their main functions will never sell, no matter how sophisticated their details are.

In the present, the use of Computer-Aided-Design (CAD) systems has significantly improved designer’s productivity and the quality of designs. However most of these CAD systems focus on the downstream design activity, i.e., detailed design, while have little impact at the conceptual design stage, in particular, to conceptual die design, due to two main issues:

(a) they have concentrated on geometrical modeling, as opposed to providing support for functional modeling that is

needed at the conceptual design stage; and (b) they don’t possess the ability to draw conclusions from incomplete and approximated information, in particular, functional information.

At the heart of the conceptual design stage lies the conceptual synthesis activity of feasible design solutions, i.e., how functional requirements of a design problem are transformed into feasible initial design solutions. Functional modeling approaches are promising for supporting such a synthesis activity by describing problems and solutions in terms of their functions, and allowing reasoning about them from functional hierarchy. We believe the explicit use of a functional model provides a good basis to generate various design solutions, because function is a higher level of abstraction than structure and enables design efforts to be more focused. The function search space will be smaller than the structure search space.

The study presented in this paper focuses on providing conceptual support for die structure design by using a functional modeling approach. The work was inspired by many research projects currently being pursued in the field of functional modeling. The developed conceptual die design system, though built upon ideas collected from the mentioned literature, differs from them in that it has developed a new functional modeling framework to represent design problems and solutions comprehensively through various functional reasoning steps including functional decomposition, functional supportive synthesis and function-structure mapping. In addition, the functional modeling approach has not been addressed in the literature of die design research.