The 3D printer is the hottest tool to bring into classrooms these days. They are the talk of the town. In lots of ways, they are amazing machines. It possibly more ways, they are tricky classroom tools. Most of them take plenty of tinkering and tuning, print times are long (a 1 hour print for all 50 students in a grade can be a week or more in the making), upkeep is time consuming. Lots of little quarks.
However, where they have excelled in my classroom is in printing construction brackets. If we aim to print small parts to be used to let students build bigger structures you can kill a few birds with one stone. Print times are reduced, and you have a build to pull students away from the computer screen.
I wanted to share a few examples, and how I use them in my classroom. First up, the simplest. Brackets to join straws at different angles. I took inspiration from Makerbot’s Speedy Architect project for this one. These pieces are tiny, taking less than 10 minutes on our Printrbot Simple Metals using my super-duper fast printing profile. Currently, the 6th grade is designing architectural models using these brackets. They will be adhering to uniform proportional scale for the structure (about 1″ to 10′), and will be closely monitoring a the cost of production. Straws cost $100 per inch, and 3D prints cost their real life cost, times a thousand, or about $20 per basic bracket.
I’m super excited to see how this project turns out. There are lots of great math connections to the 6th grade curriculum using the scaling and the economy system. The structures are bit innocuous from the structural engineering perspective, but the amount of iterative design & 3D printing we can pull off while printing such small parts will make this project worth while. We are lucky enough that each of our groups of 4 will have their own 3D printer to operate during class time, keeping the project rolling at a fast pace.
Up next, there are the balsa wood brackets, that came from the Zazouck project on Thingiverse. These parts are a bit different than the straws in that I use them exclusively as construction tool. The parts are all printed ahead of time, sorted into different types and they are used to do rapid fire construction challenges. Most recently students were tasked with building a 12″ bridge, while controlling for the cost of parts and materials used to build the bridges.
These pieces are great for rapid construction. They lack in the structural consistency that using glued joints might give you, but they let students build quickly. Often, balsa breaks in the brackets, but a drill bit reams them out pretty easily. These are great bits, and took about 30 mins to print a set of each piece. To get a classroom set of about 20 of each part, I had the machines running constantly for a few days. But now they are done and we have our own custom construction set…in colors that match the labs floors!
Last up, we’ve got the most complicated component yet. The craft stick brackets. These pose the most difficult design process of the three, but I think it gives the most rewarding final product. Requiring constantly being aware of stick orientation in regards to slot location on the brackets. I think the challenge of the design makes these an awesome candidate for creating a lesson on using Fusion 360 assemblies to virtual design structures before printing them. This is something I’ve got in the pipe for the 7th grade next semester.
All of these follow a basic principle. Find a material that is cheap and plentiful in you lab, and design brackets to join them at different angles. Have students design the parts, even model the whole structure in CAD before printing. Cut down print times, end up with bigger and cooler parts…its a win win all around. Have you done any construction projects like this? Let me know!