Q:

Snap fit on an enclosure

I am designing an enclosure, and top and bottom should be linked thanks to snap fit. I have to use 3D-printing to make both parts. The material is ABS. I made some trials, but they keep breaking. I am using the design in the following picture.  Do you have any idea about how I can strengthen them or something else to prevent them from breaking ? Thank you for your help !

A:

3D prints are weak in the direction of each layers plane. You could try to make the part in a different orientation.
Second thing to try is to use a coarser print. My friend tested mechanical properties of different 3D prints and concluded that the printers were worse the smaller the layer size was. Even materials that technically better didnt do well in a real test since the failure mode is not in the material itself but rather the bond between layers. Finer layers having more seeds for the error to start from.
You could also strengthen the print with some other material by sewing or taping something on the part.

A:

In addition to joojaa's excellent advice, you might try reducing the height of the interference and/or increasing the length of the flexure to which it is mounted — such changes would reduce the internal stress in the plastic to manageable levels.

