For the last design I turned Flexbot into FlexCar, but the gear set was not made by ourselves. This time I designed the model and 3D printed the gear set. The motor spins quite fast. So we need to use the gear set to slow down the speed. The speed reducing ratio is 1:52 and the overall size: Length: 59 ; Width: 77 ; Height: 20 mm.

Materials and equipment needed (most of them can be found at home)

• The printer we use is FDM 3D printer, and the filament is PLA. Layer set: 0.15 mm ; Extruder diameter: 0.55 mm
• Core from common rivet (Diameter: 2 mm) and chopsticks (diameter: 5mm) as the shaft of the gears; Two metal axles (Internal diameter: 5mm External diameter: 10mm Height: 4 mm)； lubricating oil

We printed out the gear set and it actually worked. But the accuracy is not enough due to the 3D printed components, which leads to much noise when the gears move, sounding like the impact drill drilling on the wall.

The smallest motor connecting with the core-less motor: m=1, z=7. The installation diameter of the axle is 1 mm. The slips happen a lot between the gear and the axle.

It would be great if you have some ideas or suggestions for this design so that I can improve it : )

We are on GrabCAD https://grabcad.com/library/flexcar-gear-set-1