A HIERARCHICAL-CLASSIFICATION SCHEME TO DEFINE AND ORDER THE DESIGN SPACE FOR INTEGRAL SNAP-FIT ASSEMBLY

The diversity of integral attachment snap-fit feature types (e.g. cant ilever hooks, bayonet-fingers, compressive hooks, annular snaps, and o thers), and their possible combinations, sizes and locations and orien tations on par-ts to enable assembly has made it appear that design po ssibilities may be unbounded. Attempts at understanding, no less optim ization, seemed intractable. This paper presents a hierarchical classi fication scheme that brings order to the design space, and uses that c lassification scheme to define boundaries and size of the design space for achieving attachment at a level above feature detailing. Classifi cation is bused on the essential geometry of parts being assembled. Th e result is surprising order and simplicity, and the ability to reduce viable options for any assembly situation to a number (e.g. 8-10) tha t will permit true optimization.