How to Build Anything Out of Aluminum Extrusion and 3D Printed Brackets

The real power of 3D printing is in infinite customization of parts. This becomes especially powerful when you combine 3D printing with existing materials. I have been developing a few simple tricks to make generic fasteners and printed connectors a perfect match for aluminum extrusion, via a novel twist or two on top of techniques you may already know.

Work long enough with 3D printers, and our ideas inevitably grow beyond our print volume. Depending on the nature of the project, it may be possible to divide into pieces then glue them together. But usually a larger project also places higher structural demands ill-suited to plastic.

Those of us lucky enough to have nice workshops can turn to woodworking, welding, or metal machining for larger projects. Whether you have that option or not, aluminum extrusion beams provide the structure we need to go bigger and to do it quickly. And as an added bonus, 3D printing can make using aluminum extrusion easier and cheaper.

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Ask Hackaday: What can you do with Origami?

At some point, most of us have learned a little of the ancient art of origami. It’s a fascinating art form, and being able to create a recognizable model by simply folding paper in the right order can be hugely satisfying. Most of us move on to other pursuits once we master the classic crane model, but the mathematics behind origami can lead some practitioners past the pure art to more practical structures, like this folding ballistic barrier for law enforcement use.

The fifty-pound Kevlar and aluminum structure comes from Brigham Young University’s College of Mechanical Engineering, specifically from the Compliant Mechanisms Research program. Compliant mechanisms move by bending or deflecting rather than joints between discrete parts, and this ballistic shield is a great example. The mechanism is based on the Yoshimura crease pattern, which can be quickly modeled with a piece of paper. Scaling that up to a full-sized structure, light enough to be fielded but strong enough to stop a .44 Magnum round, was no mean feat. But as the video below shows, the prototype has a lot of potential.

Now it’s your turn: what applications have you seen for compliant mechanisms? Potential applications range in scale from MEMS linkages for microinjecting cells to huge antennas that unfurl in orbit. We’ve featured a few origami-like structures before, like this self-assembling robot or a folding quadcopter, but neither of these really rates as compliant. This elegant parabolic satellite antenna is more like it, though. There are applications for designing origami and a mathematical basis for the field; has anyone tried using these tools to design compliant structures? Sound off in the comments below.

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Print Your Own Vertices for Quick Structural Skeletons

3D printing is great for a lot of things: prototyping complex designs, replacing broken parts, and creating unique pencil holders to show your coworkers how zany you are. Unfortunately, 3D printing is pretty awful for creating large objects – it’s simply too inefficient. Not to mention, the small size of most consumer 3D printers is very limiting (even if you were willing to run a single print for days). The standard solution to this problem is to use off-the-shelf material, with only specialized parts being printed. But, for simple structures, designing those specialized parts is an unnecessary time sink. [Nurgak] has created a solution for this with a clever “Universal Vertex Module,” designed to mate off-the-shelf rods at the 90-degree angles that most people use.


The ingenuity of the design is in its simplicity: one side fits over the structural material (dowels, aluminum extrusions, etc.), and the other side is a four-sided pyramid. The pyramid shape allows two vertices to mate at 90-degree angles, and holes allow them to be held together with the zip ties that already litter the bottom of your toolbox.

[Nurgak’s] design is parametric, so it can be easily configured for your needs. The size of the vertices can be scaled for your particular project, and the opening can be adjusted to fit whatever material you’re using. It should work just as well for drinking straws as it does for aluminum extrusions.