What is the scale of "shrink" at automotive/heavy manufacturing?

Since there are a few members here in manufacturing:

In heavy manufacturing, what is the scale of damage along the line? At what point is the product scrapped? If a product is damaged to the point where it will not be considered for repair, is it broken back down to parts, or is it cheaper to destroy/dispose the entire assembly?

depends

What are we making? Whole cars? I've toured a modern auto plant. At the end of the line there's a full blown shop for any defects, mostly paint issues. If they say dropped one off a high conveyor or something, I'd assume the whole unit is disposed of on account of logistics of dismantling it, figuring out what lived, working the serialized parts back into the line, etc.

I have a friend who worked in that style re-work, body shop at the Ford Van Plant in Ohio. Most of his work was pre-paint like cutting off misalligned body panels then manually rewelding correctly.

I know that if there's more than a certain amount of damage, manufacturers aren't allowed to sell the car. In the case of Mazda, these cars are supplied to race teams, driving schools and the like. You have to sign a paper saying that you will not resell it OR the drivetrain, and there's no MSO so it can't be registered.

We got one of those. It was only barely damaged badly enough to become a donor, it was almost salvageable. Of course, by our standards, it was fully and easily salvageable. It looked as if it had been given a sharp pull on one of the rear tie-downs so it had a droopy butt. A couple of hours on a frame machine straightened it right up.

Don't know about what happens at the plant, but typically state law governs transportation or storage damaged cars at the dealership level and it can vary. In SC, repairs under $300 are authorized by the manufacturer via pictures etc and repairs handled at the dealership. Those repairs must be disclosed to the purchaser via those same pictures and a copy of the repair order. Over $300, the district rep will get involved. Bolt on panels such as a hood, fender etc are generally repaired if less than about $1k, cut seats damaged interior panels etc are usually repaired regardless of cost. If it requires a complete welded panel or frame pull it usually meets the fate of the Miata Keith mentioned.

When I worked at Detroit Diesel, there was a huge pit full of engines and blocks, from all along the assembly line. If an engine was 99% assembled and it fell over while being transported, the entire thing was dumped into the pit. The manufacturing process had all the pieces necessary for future builds, so spare parts weren't needed. Service parts were warehoused in a building 100 miles away, so it wasn't feasible to remove the salvageable parts, tag them and ship them to that warehouse (which had it's own system of ordering.) All that hassle wasn't worth it, even for a Series 60 Detroit Diesel engine.

I know that when GM warrantees a brand new crate engine, it gets scrapped. It's not worth the effort of tearing it down and trying to diagnose the problem or save any potential parts. Even if it's just the rear cover making very slight contact with the crank, which can be fixed in minutes if the engine is out of the car...

I think the potential warranty hassles aren't worth trying to reuse parts. Loooonnng time ago when I worked for a Buick dealer (mid 90's) a forklift driver dumped a pallet of 3800 Series II cylinder heads over, he scrambled to put them back on the pallet and didn't tell anyone, afraid he'd lose his job. Those heads went all over the country and a fair number had bent/sticking valves. If there were, say, 100 heads on the pallet, 30% were damaged and each one was $800-$1000 to replace under warranty it adds up pretty quick.