Abstract: Product design is considered as constraint satisfaction problem (CSP), and an approach is proposed which is methodology based-on constraint network. In the process of product design, it is the crucial task to meet the requirement of product function, and research all kinds of variables and constraints, then abstract design constraint system to express the essential of the design activity with the theory of design environmental and design system. Constraints attached to the product design process are divided into three kinds according to their attributes, and expressed by graphic theory and construct constraints network, then constraints can be run in the constraint network under the control of the constraint mechanism to acquire the design chains. The conceptual design scheme can be got by decoding of the information stored decoded in design chains, which provides an approach to the mechanical product design auto-mation.

Key words: Constraint network, Conceptual design, Constraint design, Design automation, Methodology, Bézier, Five-axis, Trajectory generation, Corner rounding