This Sunday afternoon, I sat down at the PC to do some modeling, at 2:30pm. I had planned to work until 4 and then to go outside. As 3d modelling goes, I looked up again at 8pm.
One of the projects of the day was version 2 of the Copter Shock Wheels. Two of the four original wheels have developed broken spokes. the failure points are mostly near the “folds” in the spokes. Version 2 is going to use regular coiled spokes instead of folded spokes, for more even load handling. Version 2 will also be stiffer overall, to give the copter a better horizontal stance when resting. A “heavy” variation of v.2 will add some extra branching in the spokes to absorb impact loads.
After v.1, my dad, an engineer, asked why I did wheels at all, instead of a linear solution. The copter does not roll, after all. As a 3d-printed solution, wheels are easier to achieve. They can cope with sideways forces in non-vertical landings, and bring some redundancy. Having said that, I am looking forward to trying a linear solution in the future, as a linear solution will be inherently more efficient. The project will again be 3d-printed at Shapeways.com, using the “light, strong & flexible” material.
About 3d printing:
The 3d printer deposits tiny amounts of plastic on top of each other, following the structure of the 3d model data, and fuses them together. The print head moves from point to point in a given plane, skips the empty points and prints the non-empty ones. When one such plane is complete, the print head moves upwards a tiny bit, and then prints the next level. The result is a detailed layer-by-layer “print” of the original model, in three dimensions. Some 3D printers use powder, and then fuse the powder together by pointing a laser at it. Others use drops of hot liquid material that fuses and hardens as it cools. Many other materials can be used besides plastics, for example ceramics and metals.
Online 3D printing services let users upload models to print. These services use high-end machines that generate very nice output. There also are affordable 3d printers that can be assembled and used at home, such as the Makerbot series of devices. These machines work in similar ways to the professional systems. They make some compromises in terms of materials, detail, and speed, but are quite compelling.