Toyota has been rebuilding its lines since 2015
In 2015, Toyota set a goal it called “simple and slim”: cheaper plants, less conveyance, shorter lines and equipment that can move. This guide covers four changes that came out of it.
- 2015Toyota sets a target of about 40% less plant investment than in 2008.
- Sept 2023Unfinished cars drive themselves through assembly in a demo at Motomachi.
- Dec 2024The first gigacast Lexus slips from 2026 to 2027.
- Aug 2025Takaoka Line 1 becomes Japan’s first line built only for electric cars.
- Mid-2026Toyota cancels that Lexus in an investment review.
A line that changes shape over a weekend
Takaoka Line 2 is a stretchable line (伸縮自在, shinshuku jizai). The equipment sits on wheels instead of in pits. Each station runs on one cable. Self-guided carts carry the cars instead of a fixed conveyor.
Toyota can reconfigure it over a weekend, and it cost about half as much as the older line next to it. Lean researcher Christoph Roser checked these details on site.
Cars that drive themselves through assembly
In September 2023, at its plant in Motomachi, Toyota showed bare electric car platforms driving themselves through assembly. Cameras and laser sensors in the plant guided them at 0.36 km/h. There was no conveyor.
Production chief Kazuaki Shingo set the goal as halve the processes (工程1/2, kōtei nibun no ichi). These are company targets, not yet proven at full production.
Why remove the conveyor?
A conveyor fixes how many cars a line can build and in what order. A line made of floor space and software can change its length, speed and route.
Parts of this already run at Motomachi. Finished cars drive themselves from the line to the yard, and robots lift the tires. Assembly without a conveyor is still being tested.
Gigacasting with a 20-minute die change
Gigacasting makes a large part of the car body as one cast piece. At its Myochi plant, Toyota cast a rear underbody that used to take 86 parts and 33 processes. It took about 3 minutes.
Toyota’s target for changing the die, the mold, is about 20 minutes. The industry norm is about 24 hours. That is SMED, Shigeo Shingo’s single-minute exchange of die, applied to the largest casting machines in the industry.
The first gigacast car was cancelled
The first car meant to use it was the Lexus LF-ZC. Its launch slipped from 2026 to 2027. In May and June 2026, Toyota cancelled it during an investment review.
Toyota says gigacasting will move to a later SUV. Meanwhile, its conventionally built bZ became the third best-selling electric car in the US. The casting method works. The product plan around it changed.
The opposite: a car built by hand
The GR Factory at Motomachi builds the GR Yaris and GR Corolla with no conveyor and no takt, the fixed pace of a line. Each car sits on a stand while skilled workers build it.
Toyota added welds to make the body stiffer, and inspectors drive every car on a test course. Toyota executive Mitsuru Kawai says, “To be the master of the machine, you have to have the skills to teach the machine.”
Old lean ideas in new machines
Toyota runs both extremes in the same plant: cars that drive themselves, and cars built by hand. It picks the method for each product. Each change applies a lean idea Toyota already had.
- A line that stretches
- Changeover thinking, applied to the whole line.
- A 20-minute die change
- SMED, applied to the biggest machine in the plant.
- Cars that drive themselves
- Moving parts around is waste, so remove the conveyor.
- The GR cell
- Keep hand skill where the product needs it.
The risks are real. Halving the processes, and lines run by software, put pressure on standard work and takt. The Lexus cancellation shows that a good production method still depends on the product plan.