Generation of design data for a post & dome snap-fit feature

This paper provides design information for the initial sizing and optimization of the post & dome snap-fit feature. The post & dome is a very efficient, high-performance, and versatile snap-fit that will be of strong interest to the plastic part design community. It is self-datuming, can take some shear loading in addition to retention, and its basic topology can be modified in several effective ways. The post & dome is currently under-utilized in plastic part design due to a lack of sizing equations, design knowledge, and recognition of this feature. Guidelines for initial sizing are formulated by considering the mouldability of the structures as well as by balancing the strength of both the post and the dome segments. Equations for maximum strain during insertion, maximum insertion force, and retention force are formulated in terms of the post & dome's defining geometry. These are based on finite element and design-of-experiment results from a previous study. If the post & dome's performance parameters are acceptable, the geometry of the dome can be modified as outlined in an enclosed flowchart. This flowchart and associated design process allows the synthesis of a post & dome for specific loads and/or spatial constraints.