Economy Class Tank

thingiverse

This is a functional tank model that can be used as a foundation for mobile robots. Number of components required to print: - body (needs support) or bodysupport (already included with clearance 0.5mm but may create unsightly interfaces) - side x2, one mirrored (or sidetaller, see below) - sprocket, axle, idler, and all gears x2 - wheel x8 - link x62 Optional: - clip x4, for holding controller pcb with variable size on top of it - hanger x4 for holding battery holder - batholder for securing 2x 18650 battery holder - boardholder (with more hanger x4) for placing something I have not thought about yet Non-printed components needed: - dc motor, 130 size, x2 - m3 screws 20 mm and 30 mm + nuts After the initial test, I found that the tracks were rather slack but would be too tight if reduced by 1 link. So I modified the wheel suspensions to be 2 mm taller, but I have not tried it yet. I use a 3-volt dc motor with 2x lithium at 8 volts consciously, and I use PWM to give the motors about 40% duty cycle to keep them from overheating. Full power is reserved for short bursts (which I have never tried, only imagined). For securing the small gear to the motor axle, I need to arc-weld the motor axle with 12v, 7Ah lead acid battery. With one large crocodile clip connecting the axle to battery terminal and another clip holding scrap sheet metal bit connected to the other battery terminal, I shorted the battery momentarily through the axle and the metal bit several times, melting a little from the metal bit and creating rough parts on the axle at various positions which will grab the gear firmly. Sparks were flying though, I know it is hazardous. Any suggestions? (superglue - not strong enough) Oh, and you might want to print the axles 100% solid and lubricate them. Mine heats up from friction and twists and bends. The solid version works so far for 2 days however.