It seems like the thing that helped American auto makers "bounce back" after things went extremely south before 2010 is also their biggest Achilles heel outside of being inherently gas-based vehicles: their choice to create entire lines of cars that's profitability hinged on the interchangeability and cross-model compatible frames and parts is also the reason they can't simply "re-tool" or redesign any of their models without completely scrapping the ideas and starting from scratch.
In a sense I almost feel like if these car companies decide to do as much they may have to entirely scrap previous car models and start anew. Imagine Ford saying goodbye to the F-150 / general truck models, the Mustangs, the Explorers. Chevy and Dodge saying goodbye to the cars and trucks they are able to sell to law enforcement, military, and government.
I really can't. Maybe I'm oversimplifying things but from my outside, rookie POV it seems like these are huge reasons due to the fact that their entire manufacturing supply line is reliant on this model that's helped them all but die off in competition to foreign auto makers.
They're betting their entire North American future on light trucks and SUVs.
https://evannex.com/blogs/news/excuses-excuses-big-auto-can-...
They're putting new nests in existing machines. The fundamentals are largely unchanged. Yeah, the dies in the presses for forming body panels change shape. But they are still made the same way. And, for example, the shape of the engine mounts are not compatible from one year to the next...but the vehicles all have engine mounts.
Changing the form of engine mounts or getting rid of them all together is in effect the same thing and purely driven by design. In fact, getting rid of engine mounts makes production a lot faster and cheaper. So yeah, retooling in that regard means re-tooling. They will loose some benfits from their plattform strategies, but that is the main reason most EVs from traditional car makers are, as of now, based on existing plattform. Given a positive business case new plattforms will be developed soon enough, if need be. And EVs can still benefit from other common parts.
EDIT: The exption to the plattform usage is BMW, they went the opposite way. Also to develop knowledge on the use of composite materials that can be used in oter model lines. So yes, there are some generalizations in my post one can find counter examples to.
During assembly the dimension of a particular beam don't matter that much. The fact that this beam has to moved through an assembly line does. Once you remove that beam assembly is getting a lot easier.
You are right regarding swapping a fuel tank for a battery. But that was before they went to re-tooling assembly lines for EV vehicles. So it is easoer to run both cars through the same, specialized line. But that is the whole point, isn't it? Once these manufacturers did the re-tooling that doesn't matter anymore. And as soon as number go up even existing plattform are not that important as the are now.
You're right, I'm not an ME. I'm a controls engineer...and it's the same software, controls, and 90% of the machine that run your different tools for different years.
But the quoted sentence is the important one. You can change the shape of a beam...but that beam is there in your process because you assume that there's no structural battery pack to take the load instead, or that there is a huge, heavy, rigid engine block under the hood that needs to be accomodated. If you changes those assumptions you would need more than new tools to go on the current presses and robots and conveyors, you'd need a whole new process.
I have installed brand new machines less than a mile south of Greenfield Village at the Ford Product Development Center, where they're willing to spend millions on new equipment to develop new products but not really thinking about building new processes.
The little differences can have huge impacts: Tesla batteries are just a few inches wider than the Bolt's, but those few inches mean wiring has to go through the roof or side rails instead of a more conventional route. That's a really seriously large change for some cars. They potentially have to run wiring before the interior, drive or battery goes in- completely changing the factory floor.
but now if you want that integrated glass screen, you put software division and that new CTO just hired from AmaGooSoft, right at the top of the tree - want your lights susystemn to have screen real estate - talk nice to the new guy. If you think the other division heads will take the new guy lying down, I have a bridge to sell you.
The point being that it's easier sometimes to let Schumpter destroy a company with the wrong PoV and let the market raise a couple of others with the right pov. After POV is worth 20'IQ points.
This also explains to large degree the momentum these compabies have once the move. And don't even talk about first time pass yield for the Model 3 compared to other companies out there.
EDIT: Typos