Motivation

1. Serves as a way to mount boards to the car

2. Protects against water ingress

Design Guidelines

Connector

Ensure that there is sufficient space to easily access the connectors used:Standards - Schematic | Connectors. Many of them are locking, so clearance for and access to the locking mechanism is required.

Retainment

The PCB should be retained in such a way that it can be removed without risking damage. It should be secured in all axes to a degree sufficient to overcome expected vibrations (ie. not press fit).

3D Printing Guidelines

Thin Walls

Wall should not be made thinner than 1mm. Remember that FDM printers can’t print arbitrary wall thicknesses on the low end. You can’t print a 1mm vertical wall with a 0.4mm nozzle, it will probably turn out closer to 1.2mm.

Wall thickness:

1.2mm - Thin walls that don’t need to bear any load (ie. a cover for a PCB), pretty flexible

2.0mm - A reasonably stiff wall that can support some light forces (screws for the enclosure, etc)

3.0mm - Probably never needed for a PCB enclosure