android04

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Aluminum metal sheets are not used for MY, only Model S&X as far as I know. But it's much more likely that's the regular steel for MY
Model 3 and Y use aluminum for the hood and door skins. Non-gigacasting models (currently only Model 3) use a lot of aluminum panels for the trunk and sub-trunk areas and for the trunk tub.
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Model 3 and Y use aluminum for the hood and door skins. Non-gigacasting models (currently only Model 3) use a lot of aluminum panels for the trunk and sub-trunk areas and for the trunk tub.
Thanks, I didn't know that. Is it the same for all factories or it varies?
 

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Apart from the stainless question, are those even large enough to make an exoskeleton w/o welding?
Interesting point.
I was in the clothing business for 20 years, and have watched many cutters go about their job.
Laying out the patterns in order to get most out of the meterage is key to a cutters job.

The side sails are easy enough, just reverse and cut them out of a rectangle.

The width of the SS roll could be just enough to cut out 2 doors with very little waste. Both sides of the bed can be laid out one on top of the other too.

The back gate, the front grill, could also fit length wise to fit the width of the roll.

Close enough. So far so good.

But then we get to the 'V' across the top of the doors, going across the front side seemingly cut out of one piece... and I have put a red arrow where its bent.

This bend at the red arrow needs to be welded, otherwise there is heaps of waste.



Tesla Cybertruck Stainless steel rolls spotted during delivery to Giga Texas today (9/20/22) ? 1663774508604


Apart from that, it looks pretty spectacular.. as far as wastage goes.
I'm going to guess the dimensions /design of pieces were also tweaked to get the most out of a sheet.
 

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Knowing you’re half taking the piss: since Elon claimed the CT is angular because the steel is so “hard” (incorrect term) that it would break presses (incorrect consequence), I can’t imagine that a rolled-up steel sheet would be relevant to any “test”
This is how the steel arrives at Starbase. Big rolls. That are then rolled out, cut and scored and folded and welded together.

-Crissa
 

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Interesting point.
I was in the clothing business for 20 years, and have watched many cutters go about their job.
Laying out the patterns in order to get most out of the meterage is key to a cutters job.

The side sails are easy enough, just reverse and cut them out of a rectangle.

The width of the SS roll could be just enough to cut out 2 doors with very little waste. Both sides of the bed can be laid out one on top of the other too.

The back gate, the front grill, could also fit length wise to fit the width of the roll.

Close enough. So far so good.

But then we get to the 'V' across the top of the doors, going across the front side seemingly cut out of one piece... and I have put a red arrow where its bent.

This bend at the red arrow needs to be welded, otherwise there is heaps of waste.



1663774508604.png


Apart from that, it looks pretty spectacular.. as far as wastage goes.
I'm going to guess the dimensions /design of pieces were also tweaked to get the most out of a sheet.
From the beginning it was thought that the exoskeleton would be folded and that to fold it they might need to first score it and later back weld where they scored it. That would mean one large roll for the exoskeleton, but you are right about hood, doors, and bed.
 


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This is how the steel arrives at Starbase. Big rolls. That are then rolled out, cut and scored and folded and welded together.

-Crissa
strange. I’m not at all a materials expert so no real surprise that I might be confused.

But if the steel can be “rolled” and “unrolled” like this, it would seem to also be press-able. My (poor) understanding is that EM’s purported strength (not “hardness”) reports would suggest the steel itself (not the presses) would fail at any material angle of pressing - basically like trying to fold a cracker.

perhaps the cracker is a bit more soggy than all that
 

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From the beginning it was thought that the exoskeleton would be folded and that to fold it they might need to first score it and later back weld where they scored it. That would mean one large roll for the exoskeleton, but you are right about hood, doors, and bed.
I believe you are correct that the sheet will have to be scored before being bent. It's too thick to bend without the scoring... Now, Elon said the doors would be 3mm thick but didn't exactly say that the rest of the body would be made from the same gauge of steel. Perhaps more normal bending process for every other bend but the doors. Hmm...
 

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Thanks, I didn't know that. Is it the same for all factories or it varies?
I'm not sure if Model 3 made in China are using gigacastings yet that would change some of the rear structure, but I don't think so. Other than that, all Model 3 are made in the Fremont factory. The door skins and hood will all be the same aluminum material. The gigacasting is also aluminum, but the structure is different in the rear. All Model Y from the 4 factories would have gigacastings.

https://electrek.co/2017/08/22/tesla-model-3-body-alloy-mix/
 

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strange. I’m not at all a materials expert so no real surprise that I might be confused.

But if the steel can be “rolled” and “unrolled” like this, it would seem to also be press-able. My (poor) understanding is that EM’s purported strength (not “hardness”) reports would suggest the steel itself (not the presses) would fail at any material angle of pressing - basically like trying to fold a cracker.

perhaps the cracker is a bit more soggy than all that
Making a gentle curve around a roll is a LOT different than the relatively sharp curves of, say, a fender.

Cybersteel is like a kitchen knife. It's easy enough to put a slight bend in a kitchen knife vs. trying to bend that same knife to match the curve of a coffee cup.

Regular steel is like aluminum foil. It's easy enough to put a slight bend in it but... well, yeah, it's easy to form around that same coffee cup, too.
 

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I'm not sure if Model 3 made in China are using gigacastings yet that would change some of the rear structure, but I don't think so. Other than that, all Model 3 are made in the Fremont factory. The door skins and hood will all be the same aluminum material. The gigacasting is also aluminum, but the structure is different in the rear. All Model Y from the 4 factories would have gigacastings.

https://electrek.co/2017/08/22/tesla-model-3-body-alloy-mix/
Yes, they are. https://evannex.com/blogs/news/tesla-s-megacasting-technology-is-catching-on-with-chinese-automakers

The body is made out of a mix of material types, primarily aluminum, but of course a different alloy than the gigacastings. There are places in that need more strength or temperature, and they're different types of steel.

-Crissa
 


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Making a gentle curve around a roll is a LOT different than the relatively sharp curves of, say, a fender.

Cybersteel is like a kitchen knife. It's easy enough to put a slight bend in a kitchen knife vs. trying to bend that same knife to match the curve of a coffee cup.

Regular steel is like aluminum foil. It's easy enough to put a slight bend in it but... well, yeah, it's easy to form around that same coffee cup, too.
I suppose I just don’t appreciate thr “gentle” nature of the roll’s curve. Because, yes, you can somewhat “bend” a kitchen knife, butjust as you say you can’t bend a kitchen knife around a coffee cup - which is the shape of the steel rolls.

And separately, this thinking seems to be somewhat inverting the causation arrow from the one EM suggested at the launch:

EM said that they cannot bend the steel and so that is why the truck had to be so angular

he did not say that in order to achieve such an angular truck they would need to bend the steel too far

If you could bend the steel around a roll as well as unbend it, it would seem the design could have easily incorporated non-angular features? Of course, EM seems to talk loosely so…
 

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Knowing you’re half taking the piss: since Elon claimed the CT is angular because the steel is so “hard” (incorrect term) that it would break presses (incorrect consequence), I can’t imagine that a rolled-up steel sheet would be relevant to any “test”
The stainless will likely come in rolls like this.

It will be too thick/ hard to stamp, but rollers and press brakes are able to manipulate it. Stamping requires deforming the material in multiple directions and there is a lot of stretching/ deforming. Rolling or folding just bends it in one direction which is a lot simpler.

(I have no opinion on whether this is steel for the Cybertruck, could be any metal rolls)
 
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I suppose I just don’t appreciate thr “gentle” nature of the roll’s curve. Because, yes, you can somewhat “bend” a kitchen knife, butjust as you say you can’t bend a kitchen knife around a coffee cup - which is the shape of the steel rolls.

And separately, this thinking seems to be somewhat inverting the causation arrow from the one EM suggested at the launch:

EM said that they cannot bend the steel and so that is why the truck had to be so angular

he did not say that in order to achieve such an angular truck they would need to bend the steel too far

If you could bend the steel around a roll as well as unbend it, it would seem the design could have easily incorporated non-angular features? Of course, EM seems to talk loosely so…
To get stainless to keep its bent shape permanently you need to get it over the point of plastic deformation. At that point it loses material strength as it deforms at the crease, but increases panel rigidity in the direction of the bend. The trick with bending is to try not to weaken the material whilst forming its shape. (Think of bending a fork backwards and forwards along the same point until it breaks)

Whilst on the steel roll it is not plastic deformed and will mostly spring back to it's original form, with a slight curve depending on material thickness.

As for not being able to bend 3mm stainless this is not true and I think is a bit of a red herring. A 50ton press brake will do a 4ft crease in 3mm SS to make a CT door panel. The question is how do they do it without weakening the material of having to harden, or structurally reinforce it afterwards.
 
 




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