It's A Snap: Plastic Snap Latch Design Page
 As an introduction into the design of a plastic snap fit please take some time to become familiar with the notations which will be used in this software. It is important for the user to understand the dimensions and loads shown in the diagram above, and the names of the variables described to the right. Once you are ready to try out the calculator, just select the "It's A Snap" logo at the top or button of this page. |
The following notations will be used to develop formulas for cantilever beam snap fits. | ||
| M | = | Bending moment | |
| L | = | Length of element | |
| bBASE | = | Maximum width at root | |
| bTIP | = | Minimum width at tip | |
| hBASE | = | Maximum height at root | |
| hTIP | = | Minimum height at tip | |
| P | = | Snap-in force | |
| F | = | Engagement force | |
| j | = | Angle of deflection | |
| y | = | Deflection | |
| y MAX | = | Maximum deflection at tip | |
| IZ | = | Moment of inertia relative to the Z axis | |
| I0 | = | Moment of inertia for the root cross section | |
| CG | = | Geometric constant | |
| eDESIGN | = | Design or permissible strain | |
| eULTIMATE | = | Ultimate strain | |
| s(x) | = | Instantaneous stress | |
| sDESIGN | = | Design or permissible stress | |
| sULTIMATE | = | Ultimate stress | |
| n | = | Safety factor | |
| m | = | Coefficient of friction | |
| ES | = | Secant modulus of elasticity | |
It's A Snap: Plastic Snap Latch Design Page