We’ve all have projects that are done, but not complete. They work, but they’re just a few PCBs wired together precariously on our desks. But fear not! A true maker’s blog has gifted us with a detailed step-by-step guide on how to make a project enclosure.
Having purchased an MP Select Mini 3D Printer, there was little to do but find something practical to print. What better than an enclosure for a recently finished Time/Date/Temperature display Arduino based device?
The enclosure in this guide, while quite nice, isn’t the main attraction here. The real feature is the incredibly detailed instructions for how to design, model and print an enclosure for any project. For the veterans out there, it seems simple. Sketch something on the back of a napkin and take a nap on your keyboard with OpenSCAD open. When you wake, BAM: perfect 3D model. However, for newcomers, the process can seem daunting. With incredibly specific instructions (an example is “Open up a new workspace by clicking CREATE NEW DESIGN,” notice the accurate capitalization!), it should ease the barrier of the first enclosure, turning the inexperienced into the kind-of-experienced.
If you’ve been printing enclosures since the dawn of time or plastic simply isn’t your style, boy, do we have you covered. Why not check out FR4 (aka PCB) enclosures? Or what about laser cut enclosures from eagle files? Maybe two-piece boxes are more your thing.
[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.
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.