I designed an enclosure for my LED lighting controller.
It houses the circuit board, has two buttons and cutouts for the wires and IR receiver.
I printed it in white PLA and installed it with a small strip of servo tape.
3D Design Software
I have tried a number of 3D design applications from SketchUp to Solidworks. For me the most important feature of the software is that it be parametric. This allows you to make changes to the dimensions of your design and have the 3D model update without having to recreate the design from scratch.
Professional packages like Solidworks provide this capability but a license will set you back around $5,000. You can get a student license for Solidworks, but they don’t provide a Maker license.
Another interesting option is Autodesk Fusion 360 which is also parametric but is free for students, enthusiasts, hobbyists, and startups.
I am a software engineer by trade, so I normally end up using OpenSCAD. Which instead of having a rich UI to manipulate 3D objects, allows you to write code which renders a 3D model. Because everything is in code, you can parameterize any dimension or design attribute you want with variables in the code.
Open SCAD
OpenSCAD has a set of primitive shape commands like cube and cylinder which can be moved around using commands like translate and rotate and combined using commands like union, difference and intersection.
My enclosure is almost all cubes and cylinders except for the beveled edge. The triangular buttons are actually cylinders with three sides, the $fn variable allows you to define how many fragments a circle short be drawn with. Curved surfaces in 3D models are rendered as mesh of triangles.
The bevel was made using the polyhedron command that allows you to define a 3D object as a mesh of triangles.
Enclosure Design
The first thing I did was get the exact dimensions of the board and enter these as variables into my OpenSCAD design. I got the board, mounting hole and button dimensions from my Eagle board design. I looked up the board thickness on the OshPark website and the button height in the datasheet.
Then I used these dimensions to create a simple model of my board with the mounting holes and buttons. I didn’t render the board in the final design, but it was useful to check my design against.
The enclosure consists of a base and a lid, the lid has a lip which slips into the base and provides a simple friction fit. There is a variable that controls the gap between the lid lip and the box.
Dimensional tolerance of 3D printed parts is never perfect, so some prototype printing and adjustment is required. I was printing on a Makerbot Replicator 2 at 200 micron resolution and a 200 micron gap in the design worked well here. The bumpy nature of the extruded print and the slight flexibility of the PLA makes for a very nice friction fit.
The board is secured on posts in the base with pegs that go through the mounting holes and I also have posts coming down from the lid to hold the board down onto the pegs.
The buttons on the circuit board are pushed by square plungers that sit in a guide. Here a greater gap of 400 micros is required so the plungers can move freely in the guide. The triangular top fits through a matching hole in the lid and is smaller than the peg so the peg cannot escape through the hole.
Thingiverse
Thingiverse is a popular website hosted by Makerbot for sharing 3D designs that can be downloaded and printed on 3D printers.
I have shared my LED light controller enclosure design files on thingiverse. The STL files are rendered 3D meshes exported from OpenSCAD and ready for printing. The scad file is the OpenSCAD design file.