The conceptual stage of mechanical product design has been recognised as th
e most critical product development stage. This is an area which is not add
ressed by current CAD systems. In this paper, we present our work on the ab
straction and exploration of functional design information to support this
design area. We consider the exploration of relevant functional design info
rmation as an important aspect of design work during this design process. F
our aspects of functional design information are abstracted, including func
tion, behaviour, structure and working environment. The working environment
information is demonstrated as being useful to the exploration of function
al design solutions. The physical behaviour is represented by an input-outp
ut flow-of-action, contrary to the commonly-used input-output flow-of-objec
t approach (where object refers to material, energy or signal). Not only is
this approach more generic, more importantly, we argue that the input-outp
ut flow-of-object is only a physical-level design abstraction, while flow-o
f-action is a functional-level design abstraction, while flow-of-action is
a functional-level design abstraction, hence it can capture design intentio
n. Based on this strategy, we explore functional design information by cons
idering the relevant action flows between the design and its working enviro
nment, as well as between the different components of the design, including
their attributes, attribute expressions, constraints, and so on. Prototype
software has been developed to implement the proposed approaches. A simple
design example is used to illustrate the various aspects of functional des
ign information and their exploration process.