Design Tip - 5

Today's design tip will talk about the snaps. This won't be the only snap tip, the snap design is difficult enough to have a single blog. 

The first tip about the snaps will be a "silly tip". I said it is a silly tip, but should be not so silly taking into account I've seen these mistakes more than 2 or 3 times this year on the parts I reviewed.

The first point is the hole dimension. The hole dimension has to be big enough to admit the snap deflection when assembling the part. On the attached picture, the dimension 'b' has to be bigger than the dimension 'a'. How much bigger? it depends on the size of your parts and the tolerances you are working with. On the applications I work b = a + 0.5mm is more than enough, but don't take this formula as 'The Truth', understand the concept and apply it to your design.

The second issue is easier. It is important to add a chamfer on the assembly side, it will help the assembly process. Using the same angle on the snap and on the hole is the best combination.

The last point is the parting line of the hole. This point was already commented on the 2nd Design Tip. It is very important to think about the mold, and define the part design to have a robust tool.