Abstract
Many different types of snap-fits have been developed to replace conventional fasteners, and research efforts have been made to characterize their performance. It is often tedious to look for design equations for unique types of snap-fits to calculate the insertion and retention forces. If found, these equations tend to be long, complex, and difficult to use. For this reason, a snap-fit calculator has been created to help in designing integral attachment features.
Studies of seven most commonly used snap-fits (annular snap, bayonet-and-finger, cantilever hook, cantilever-hole, compressive hook, L-shaped hook, and U-shaped, hook) were used to provide the equations implemented in this snap-fit calculator, more fasteners than any other snap-fit calculator available. This tool aids in designing snap-fits to meet specific loading requirements by allowing the designer to size the feature to obtain desired estimates for maximum insertion and retention forces.
The software for this design tool was written in JAVA™ language that is independent of operating system platforms and can be distributed at a company site-wide over an intranet or worldwide over the Internet. This makes it easily accessible to a user, and universal upgrades can be achieved by simply updating the software at the server location. Designers will find this tool to be useful in the design process and the most convenient way to estimate the performance of snap-fits. This paper describes the development and operation of the IFP snap-fit calculator including several case studies comparing the calculated results to experimental data.