Rubber Band Car

thingiverse

Here is my take on the rubber band car. I had some kids in our office for "bring your kid to work day" and I downloaded the "Rubber Band-Powered Car" (RBPC) for a quick demonstration of my 3D printer. I found the RBPC very difficult to print on my Prusa i3 MK2 with Maker Geeks raptor PLA because it was not compatible with that material. The RBPC axles are integrated into the wheel and so if the axle breaks off (and it will because it was a weak design) you have to reprint the entire assembly. My design goals were to make a more robust and forgiving car that could withstand heavy use by kids and also print well on my Prusa i3 MK2. I also wanted a low piece count and part that could be printed using the fastest settings on my printer (Prusa i3 MK2 running with the "0.35mm Fast" settings). I liked the overall body shape of the RBPC so I kept that design. I redesigned the entire car to make it more reliable. First, I made the wheels and axle to be more robust (8mm axle diameter) and they can be printed separately for easy replacement. To affix the wheels to the axle, I use super glue instead of a press-fit design, but I have plenty of glue so that wasn't an issue. The axle was given a larger rubber band hook to improve traction. The rear drive wheels were designed to wrap a rubber band around the circumference to give it extra grip. Excess rubber band material can be woven in the "oval pockets" of the wheel to accommodate differing rubber band sizes. I lengthened the body so the rubber band is fully elongated at rest, and also designed it to wrap around the body hooks (slalom skiing-style) so it doesn't shoot away when the axle inevitably releases the rubber band. All parts can be printed with fast printer settings except maybe the drive axle, which benefits from a 0.2mm layer height due to the integrated, detailed rubber band hook. I included a version of the wheels with integrated axles (as an experiment and also if anyone wants to lower the piece count), but I broke the axle off the wheel assemble when removing it from the print bed. You will need to print the following parts using separate axles and wheels: 1. The body. 2. The front axle. 3. The drive/rear axle with the hook. 4. 2x front wheels (solid, 30mm diameter). 5. 2x rear/drive wheels with oval pockets (40mm diameter). OR You will need to print the following parts using integrated axles and wheels: 1. The body. 2. The front axle and wheel assembly. 3. The drive/rear axle and wheel assembly with the hook on the axle. 4. 1x front wheels (solid, 30mm diameter). 5. 1x rear/drive wheels with oval pockets (40mm diameter).