Multistage paint takes time to cure and inspect. There's no way they do this on the same assembly line that probably only takes a day to complete the car.
Yes, it takes time to dry, but if the number comming in matches the number coming out, there is no delay.
There is just a storage/stock of n cars.
So the dry time only matters at the start or stop of the whole assembly line. (e.g. parts shortage)
I imagine body parts are manufactured and painted in batches based of assumed/current popularity. So for example Toyota might place an advanced order with Subaru for 50 cars where they assume 15 will be electric blue, 15 will be red, and 5 - 10 in other colours. But if those ratios change due to people placing orders for an oversubscribed paint choice, this would push them back in the production queue a little. Let's not forget that there are a few Subaru and Toyota exclusive paint choices too.
Body parts are not painted in batches.
Its like this:
- Take sheets of steel, press them into their shapes.
- Do this for ALL parts needed, including the doors.
- Fill a SMALL stock with these parts for every car type.
When an order is executed, they take the parts, weld them and mount the doors and all other body parts (trunk, hood).
Then the complete body is washed, coated and painted.
After that, the doors are unmounted and receive a code, so you can assign them later to their chassis.
Doors are assembled somewhere different and will rejoin their car, when everything inside is complete.
And no factory will rely on a completely randomised order queue either.
Thats why i added "unknown".
The line has a specific order, by whatever... I'm sure its a mixture of several complex calculations and of course the order list.
Also the delivery dates of parts and current stock matter.
Its also not directly depending on the order how the cars were painted, because of different dry times.
But if those ratios change due to people placing orders for an oversubscribed paint choice, this would push them back in the production queue a little.
This can only be the case, if they run out of paint. Remember: Everything is "arrive right in time", to keep stocks as small as possible.
So if your observation is correct, it will be because they wait for new paint.
Every paint robot can change the paint individually for any car within seconds.
for all we know, they just paint them in the same colour in batches
No, painted chassis are not stocked, this takes to much space.
The components are stocked unpainted.
They get painted after assembly.
With that said, it appears that there is a bit of a random element to it as Toyota Online team has previously confirmed orders were being put through manually on the factory system,
This is the most logical answer. If the guy, who enters/forwards your order has a cigarette, you car may arrive 2 months later...
My commander (3 year old) forced me to watch tons of car assembly videos, from different makes and different times (from the Trabant to Porsche Taycan). Its teh same everywhere:
- prebuild parts from steel sheets
- assemble the chassis on demand/order
- mount doors
- paint everything
- unmount doors
- assemble the car
- re-mount doors (usually one the very last things)
- Quality controll
Once it reached stage 2. it will be assembled without any delay.
Every car at stage 2 is completely specified, all of its parts are arrived or will arrive in time. Its guarantied to be build completely in the next hours.
The only "way out" is when it does not pass quality controll (bad welding, bad paint, ect).
Sorry for the bad english, i could explain it very well in German.
