Snap Fit Design

Snap Fit Design
Snap fits are commonly used as an assembly method for injection molded parts. Although they have been around for many years, they have recently become more important in an attempt to simplify assembly and its associated costs. Snap fits are very useful because they eliminate screws, clips, adhesives, or other joining methods. The snaps are molded into the product, so additional parts are not needed to join them together. Additionally, if designed correctly, they can be disassembled and reassembled several times without any problems. A snap fit can either be designed as a permanent snap or a multiple snap. Permanent fits are used in disposable parts that are never meant to be disassembled. Multiple snaps are used in most designs where disassembly for service is expected.

There are complications associated with snap fits. A lot more engineering is required to design a proper snap fit than designing something for screw assembly. Snap fits can also make the injection mold that produces the parts significantly more complicated and expensive. Generally, the savings in assembly costs more than makes up for added cost and complexity of the mold.

There are three main types of snap fits: annular, cantilever, and torsional.