#Turbocase

Making a nice case for a PCB project is not terribly hard, but it is annoyingly time consuming if you just want a simple functional case. This most of the time for a case design for me is spend on figuring out how to align the mounting holes in the PCB with the 3D print and ensure the cutouts for the connectors are correct.

This project provides a hacky neat way to generate an OpenSCAD project based on the data in a KiCAD PCB file.

To define the shape of the case create a drawing of inside edge of the case on one of the user layers. This follows the same semantics as the PCB fabrication outline on the Edge.Cuts layer. By default turbocase reads the outline from the User.6 layer.

Turbocase will automatically extract information about MountingHole footprints and place plastic posts underneath the PCB to fit threaded metal inserts after 3D printing. It currently is hardcoded to the bag of M3 inserts I have.

For connectors KiCAD needs to learn about the third dimension. For this purpose I have added a "Height" property to the connects I want to be processed by turbocase that defines the height from the top of the PCB to the top of the connector so an appropiate cutout can be made in the case. The rest of the shape of the connector is defined by the bounding box of the F.Fab layer of the connector.

An example of a KiCAD PCB with a case outline on User.6:

The generated case from this file:

#Features in summary

• Generate a case from the shape defined on the User.6 layer including holes for the bottom of the case.
• Generate a lid that fits on the case automatically. Holes defined in the User.7 layer will be cut out of the lid.
• Generate mounting posts in the case that line up with the MountingHole footprints on the PCB
• Add bounding boxes for any footprint on the PCB that has a Height property defined (shown in red above).
• Automatically cut out the bounding boxes for those footprints from the case when clipping the walls.
• There is a library of extra footprints that instruct TurboCase to add extra features to the case like shaped screw holes and mounting posts for the lid.

#Installation

$ pip install turbocase

#Usage

1. Create a case outline in the User.6 layer using the line drawing tools.
2. Add the Height property to the connector footprints that need to be in the case export
3. Ensure the screw holes for the PCB are MountingHole footprints
4. Run the turbocase tool to make an OpenSCAD file:

$ turbocase project/project.kicad_pcb case.scad

#Footprints

TurboCase can automatically add prefab structures to the generated case by using the included KiCad library. The TurboCase.pretty folder in this repository is the footprint library that defines custom objects to add to the design of your case. The tool will detect any footprints that start with TurboCase: and append the correct module from parts.py into the final OpenSCAD file.

#Command line options

usage: turbocase [-h] [--layer LAYER] [--lid-layer LID_LAYER] [--bottom BOTTOM] [--wall WALL] [--standoff STANDOFF] [--show-pcb SHOW_PCB] [--lid {cap,inner-fit}] [--verbose] [--debug] pcb output

positional arguments:
  pcb                   Input kicad PCB file
  output                Generated openSCAD case template

options:
  -h, --help            show this help message and exit
  --layer LAYER         Layer with the case inner-outline [defaults to User.6]
  --lid-layer LID_LAYER
                        Layer with lid-specific holes [defaults to User.7]
  --bottom BOTTOM       Bottom thickness in mm [default 1.2]
  --wall WALL           Wall thickness in mm [default 1.2]
  --standoff STANDOFF   Height generated for the PCB mounts in mm[default 5]
  --show-pcb SHOW_PCB   Show the PCB placeholder by default [default false]
  --lid {cap,inner-fit}
                        Lid construction model
  --verbose, -v         Show log messages
  --debug               Display a lot of debugging info

#Contributing

The official repositories for this project are https://sr.ht/~martijnbraam/turbocase/ and https://codeberg.org/MartijnBraam/TurboCase. Patches can be sent to Codeberg as a pull request or to sr.ht using git-send-email:

$ git config sendemail.to "~martijnbraam/public-inbox@lists.sr.ht"
$ git send-email HEAD^

If you'd like to support development of this project and several others like this financially consider contributing to my Liberapay or Patreon.