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PETG or ABS?
03/30/2017 at 12:32 • 0 commentsThe motor mount is under a lot of stress during braking and the motor side will tend to flex towards the outer side of the board. I looked into two different polymers commonly used in 3D-printing that has relatively good stiffness and weather resistance. PETG was stiffer than ABS and in that case was a suitable candidate for the motor mount. After testing however, the dynamic forces acting upon the mount caused the PETG mount to crack. It was stiff but it was also too brittle. In the end, ABS was the suitable choice as it offers sufficient rigidity as well as flex during dynamic loads.
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Motor Mount Design: Securing Mount Radially
03/21/2017 at 19:02 • 0 commentsOne of the challenges with plastic motor mounts was to secure it against rotational forces around the axle. Sheer clamping force would not suffice as the material would fatigue under constant load. This was the reason these trucks were chosen as a suitable candidate as it has a rib geometry on both sides. The ribs contribute to the surface area in which the mount can hold onto. It was a matter of reconstructing the varying cross-sectional areas through trial and error in Fusion 360. It the end, I combined three different cross-sectional areas and used the "Loft" function to recreate my axle. I then 3D-printed test pieces to ensure a snug fit. It took me around 7 iterations to get it right.