An improved functional decomposition method based on FAST and the method of removal and operation

Functional decomposition plays an important part in the conceptual design. However, the existing functional decomposition methods for existing products have either a limitation of application scope or can not provide sufficiently comprehensive information. For these, an improved functional decomposition method based on function analysis system technique (called FAST) and the method of removal and operation is proposed. With the improved method, more information such as logical relationship of function, functional level, functional hierarchy and the relationship between function units and components can be got clearly, which are the important information for the conceptual design. The functional decomposition of a water dispenser illustrates the method's application process.