Twenty years ago, the Prius popularised hybrid vehicles and transformed the automobile industry. Will Toyota’s hydrogen fuel cell car, the Mirai, repeat the trick?
The fourth-generation Toyota Prius is manufactured at the company’s Tsutsumi plant, a few kilometres south-east of Nagoya, around 100 minutes from Tokyo by Shinkansen bullet train. From Tsutsumi’s viewing gantries, two production lines stretch away into the distance. These halls house the trim workshop. Here, completed body shells roll in, are divested of their doors (which make their way in pairs along a separate line) and the interior, hybrid system, dashboard and seats are installed. The factory, which has been making Priuses since 2003, produces 430,000 cars a year. From 6.30am to 1am, it can turn out a Prius every minute.
This is the Toyota Production System (TPS) at work, a fabled refinement that funnels the immense complexity of car-making into a series of simple stages. Each step is serviced using the just-in-time manufacturing process by the requisite parts supplier. The system is controlled by the workers themselves, who have autonomy over stopping and starting the line to resolve issues.
TPS is a mainstay of business-school case studies, as well as being widely imitated by envious rivals. The system is about efficiency in all its forms, from the constant tracking of components (kanban) to the fault-reporting system (andon), which dates back to Toyota Industries founder Sakichi Toyoda’s early days making looms. The process of constant improvement is known as kaizen. Toyota has this down to a fine art, employing kaizen teams to roam the factory and scout for potential problems and possible efficiencies. On posters, shirts and tabards, the plant’s official mascot – a cartoon horse called Tsutsuma-Kun – preaches health and safety.
In the adjoining building, stamped-steel Prius bodies are assembled robotically, using conventional welding and lasers (as well as a secret proprietary method that WIRED wasn’t allowed to photograph). Today, the 1,850 robots at Tsutsumi are sourced from one of three main suppliers: Nachi, Yaskawa and Kawasaki. As the body shells roll into position, a cluster of around ten closely spaced robotic arms swivel and pivot in a synchronised dance that is simultaneously beguiling, awe-inspiring and terrifying. Then they all lurch forward at once, finding the pinch points where two pieces join, then dab and squeeze their welding pincers along the seams to seal them. Each stage takes just under a minute, before the arms retract and the line rolls on. Large components are sent straight to the line by a system of overhead wires and gravity-driven palettes. At the same time, a constant stream of electric trains bring the rest along a miniature road system of intersections and stop signs. The building is a chorus of whirring ratchets, beeping trucks, buzzing drills, the rattle of conveyor belts and pulleys and the hum of the air-conditioning.
