|The quadcopter frame in SolidWorks|
|The design from MIT|
I then printed the part at Stanford's PRL (Product Realization Lab) using their ProJet 3D printer which uses wax support material so it would be easy to melt away after the print. After the print finished, the part looked great but I quickly realized some flaws in the design. The biggest flaw was that it just seemed too heavy. The printing material was heavier than I anticipated and as a result I had serious doubts about its ability to fly. Another problem that was made clear was that it wasn't the most sturdy design. I carelessly dropped it from my bed and one of the arms broke. If this quadcopter was to fly, it would often be dropping from height and would most likely break upon impact and since the frame was a single 3D print it wouldn't be easily fixed.
|Fresh out of the printer|
|Melting off the wax|
So it was back to the drawing board. Armed with the lessons I learned from my previous design, I decided the new version had to have several key features. It had to be lighter, this meant less plastic or at least a lighter plastic. It had to be stronger and more easily fixed. Finally it had to be more easily printed. The first version was a difficult print and may be too hard to do with a hobbyist grade machine. With these parameters in mind, I decided that the best way to do this was use carbon fiber rods for the arms and only 3D print the base that held the electronics and motor holders. This decision had several advantages. First, the carbon fiber meant less plastic and made it much lighter while also stronger. By printing out only the motor holders and electronics base, the prints were simpler, cheaper, and easily replaceable. As an added bonus, the entire frame ended up being cheaper because I only had to use about a dollar of carbon fiber and the print only took 0.66 cubic inches of support and printing material so it was a fraction of the cost of the old frame.
Check out the CAD files at: https://sourceforge.net/projects/nanoquad/files/?source=navbar.
|The revised design (the square rods are carbon fiber)|
|The printed parts. One of the problems was the support material was inside the holes which made it difficult to clean out.|
|Post support material|
|The assembled frame|
|The final quadcopter|