What is a snap-fit design feature?
Ever found the perfect fit? Maybe it was with that new dress shirt, or pair of pants. It felt right and looked great. When assembling plastic you can end up in a similar predicament: looking for the perfect design to make two or more plastic parts fit together perfectly. The concept is simple. Snap-fit designs require two main features: the protruding part in the form of a hook, stud, or bead, and the depression or undercut component on its mate. This design feature allows for you to assemble and disassemble two plastic components together easily, many times over, without causing harm to the part.
For the design engineer, the task becomes finding the perfect balance – much like finding the perfect fit of pants – between the rigidity of the material and the flexibility of the joints. Additionally, the distance in the overhang depth can secure assembly, but cause greater stress on the joints of the plastic during deflection, until locked in place, when the stress once again is alleviated. A great engineer can find the perfect balance between strength and flexibility for each snap-fit feature.
With a better understanding of what a snap-fit feature is, you may be as excited that there are alternative reasons for utilizing a snap-fit feature that go beyond design functionality.
Of assembly types, snap-fit is the most eco-friendly design. Since they are easy to disassemble, components of different types of plastic are easy to separate and recycle.
Thermoplastic injection molded snap-fit features allow for simple assembly through the form of inexpensively molded geometric shapes. No additional parts of materials are necessary in this assembly process.
Perhaps the most alluring feature of the snap-fit design is the ability to easily assemble and disassemble many times over without causing harm to the assembly.