My name is Alexandre and I my hobbies are arduino, PCB, 3D printing, laser cut...
I use FreeCAD since several years to make enclosure for my electronic projects but I don't use 3D printing to do it because it takes time to print except for small parts.
I prefer to use laser cutting which is faster and allows to make larger boxes.
In order to make my work easier, I have developed a module for Freecad that allows to create connections between parts from Part/PartDesign workshops. Then, an export tool projects parts on a 2D plan in order to save outlines as Flattened SVG. SVG file is then reworked on Inkscape before being sent in cutting.
An example :

Module manages connection of type tab/slots, T-slot joints and crosspiece. It also allows to create rounded corner with living hinges.
Python source code and documentation is on GitHub : https://github.com/execuc/LCInterlocking
If this module corresponds to the freecad philosophy, I would like to propose it as an addon via the FreeCAD addon manager. So do not hesitate to say what you think about it.
Thank you