Practical Enclosure Design, Optimized for 3D Printing

[3D Hubs] have shared a handy guide on designing practical and 3D printing-friendly enclosures. The guide walks through the design of a two shell, two button remote control enclosure. It allows for a PCB mounted inside, exposes a USB port, and is optimized for 3D printing without painting itself into a corner in the process. [3D Hubs] uses Fusion 360 (free to hobbyists and startups) in their examples, but the design principles are easily implemented with any tool.

One of the tips is to design parts with wall thicknesses that are a multiple of the printer’s nozzle diameter. For example, a 2.4 mm wall thickness may sound a bit arbitrary at first, but it divides easily by the typical FDM nozzle diameter of 0.4 mm which makes slicing results more consistent and reliable. Most of us have at some point encountered a model where the slicer can’t quite decide how to handle a thin feature, delivering either a void between perimeters or an awkward attempt at infill, and this practice helps reduce that. Another tip is to minimize the number of sharp edges in the design, because rounded corners print more efficiently and with smoother motions from the print head.

The road to enclosures has many paths, including enclosures made from FR4 (aka PCB material) all the way down to scrap wood with toner transfer labeling, and certainly desktop 3D printing has been a boon to anyone who’s had to joylessly drill and saw away at a featureless plastic box.

Designing And Printing A Custom Enclosure

enclosure

So you know how to design a circuit board, assemble the parts, and have a functional device at the end of a soldering session. Great, but if you want to use that device in the real world, you’re probably going to want an enclosure, and Tupperware hacked with an Exacto knife just won’t cut it. It’s actually not that hard to design a custom enclosure for you board, as [Glen] demonstrates with a custom 3D printed project box.

[Glen]’s board, a quad RS-422 transmitter with a PMOD connector, was designed in Eagle. There are a vast array of scripts and plugins for this kind of mechanical design work, including the EagleUP plugins that turn an Eagle PCB into a 3D object that can be imported into SketchUp.

Taking measurements from Eagle, [Glen] designed a small project box that fits the PCB. A few standoffs were added, and the board itself was imported into SketchUp. From there, all he needed to do was to subtract the outline of the connectors from the walls of then enclosure for a custom-fit case. Much better than Tupperware, and much easier than designing a laser cut enclosure.

Once the enclosure was complete, [Glen] exported the design as an STL, ready for 3D printing or in his case, sending off to Shapeways. Either way, the result is a custom enclosure with a perfect fit.