Instead of using fixed conveyors rooted in pits or hangers that dangle from lines along the ceilings, the new technique uses flat palette platforms that skate along dolly rollers.

The platforms are big enough to support the whole vehicle and have floors flush with their surroundings. Workers can easily walk about the cars and work on them from any angle without having to dodge hangers or step over conveyors. The palettes also can be crammed together closer in the line, meaning that work processes can be combined and the line length trimmed.

When the platform comes to the end of a line and needs to do a U-turn, the palette simply slides to the side along the dolly. There is no need for costly robots to transfer the car, and the system allows Mazda to extend a line by just adding sections of rollers when demand increases.

Where it used to take Mazda six weeks to extend a line, it can now be done in only seven days.

The new dolly system improves overall final assembly productivity by 25 percent.

Another advantage is that it allows flexibility for making EVs on the same line as those with internal combustion engines. Before, a fixed line would lift engines, suspensions or transmissions into a vehicle’s bodies at set spacings. Now, those component systems are delivered to the line by fleets of automatic guided vehicles, or AGVs.

The AGVs zoom up under the vehicle body and align themselves perfectly for whatever kind of vehicle they are trying to build—with one AGV handling the front, another AGV the back.

This allows Mazda to flexibly accommodate any combination of long or short vehicles on the same line, with any number of powertrain variants, including all-electric, all-wheel-drive, hybrid, and even a newly developed longitudinally mounted transmission for rear-wheel drive vehicles.