> The metal panels have oil on them in stamping, and they MUST stay oiled right up to the point where the body takes it's first bath.
I toured an assembly line a few years ago. The guide told us that in the 1970s they had teams of people watching iron/steel prices, when they thought the prices where at the low they made a massive order of all iron that factory would need for the next few years. When the factory when to just-in-time (sometime in the 1980s or 1990s) they couldn't do that anymore - but they also got to get rid of all the equipment to de-rust all that stored iron: since every raw material was shipped out as a final assembly in a week there was no time for significant rust to form and so they avoided a lot of problems.
I don't work in that area, but I suspect that is done. Auto makers also have the ability to order months in advance so they can yet discounts because the steel makers know what orders they need to fill each week instead of a lot of overtime to fill a large order.
Thisbis done, of course. Risk with securing long-term prices so is that those prices might be higher than short term ones for the same future period. So usually, admittedly it is a while I did raw material procurement and aerospace is different, you use a combination of both.
You can still get squeezed so either way. But that has close to nothing to do with JIT, JIT just concerns the delivery bit (over simplified of course).
I toured an assembly line a few years ago. The guide told us that in the 1970s they had teams of people watching iron/steel prices, when they thought the prices where at the low they made a massive order of all iron that factory would need for the next few years. When the factory when to just-in-time (sometime in the 1980s or 1990s) they couldn't do that anymore - but they also got to get rid of all the equipment to de-rust all that stored iron: since every raw material was shipped out as a final assembly in a week there was no time for significant rust to form and so they avoided a lot of problems.