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For everyone concerned about repairs-- this isn't exactly a new concept. The BMW i3 has a carbon fiber frame that, as far as I know, they do not sell in sectio

For everyone concerned about repairs-- this isn't exactly a new concept. The BMW i3 has a carbon fiber frame that, as far as I know, they do not sell in sections (https://www.cnet.com/roadshow/news/crash-your-carbon-fiber-i3-ev-heres-how-bmw-will-fix-it/ https://www.cnet.com/roadshow/news/crash-your-carbon-fiber-i...). This means during an accident, the damaged portion is cut out and a new section is glued in, though the repair would likely involve purchasing an entirely new frame unless the shop has one leftover from a previous repair. With the Y, it'd be the same thing-- the shop would either have a spare, partial casting from a previous repair or need to order a new one, and it would be cut and welded into place. The repair itself shouldn't be any more difficult than any other car, it's just purchasing the part that becomes more expensive if you have to purchase a new entire casting for damage in one area of the car. That, however, is entirely fixable through some clever supply chain fixes and may be something Tesla can support through savings on the single casting.

Aeolun 6y ago
It seems to me that cutting out, and welding or glueing in a new part had a serious effect on the structural integrity of the vehicle.
- andrewmunsell 6y ago
  I'm sure there's some cases where that might be true or it's not practical for other reasons (I'm not an automotive engineer or anything), but remember, the 3 has ~70 parts welded together for this same area of the car, so welds themselves are not fundamentally bad.
  - thesimp 6y ago
    Just as the BMW i3 the Alfa Romeo 4C also has a carbon fiber monocoque: https://www.toraytac.com/media/story/XkKY/Alfa-Romeo-4C-Monocoque https://www.toraytac.com/media/story/XkKY/Alfa-Romeo-4C-Mono.... And Alfa Romeo has published a 162 page manual for bodyshops on how to do repairs. The PDF is out there in the internet for people that want to know the technical details.
  - MaxikCZ 6y ago
    I dont think the main concern here is that the new part would be welded in. When the car is in design process, each weld is carefully calculated to provide the exact binding force at the precise location. In case of accident, the car is modeled to crumble just right to absorb maximum energy without compromising cabin space, thus protecting occupants. The process of cutting out and welding in parts almost always means altering the stiffness of such bonds (and/or moving the bonds to different locations), which can be very dangerous in the event of accident
- gfody 6y ago
  my thoughts as well, otherwise what was the point of casting it whole in the first place?
  - andrewmunsell 6y ago
    The single casting for the Y is for cost an NVH reduction per the article & Elon. My early production Y has 4 pieces for the rear instead of the single one this new machine will produce, but it shouldn't be any structurally less sound
  - TomVDB 6y ago
    All the remaining advantages that are mentioned in the article: cost, weight reduction -> increased autonomy, better handling and driving comfort.
  - bronson 6y ago
    The point is: "We're moving to an aluminum casting instead of a series of stamped pieces. We'll go from 70 parts to 4, then 1 with a reduction in weight, improvement in [NVH], reduction in cost, and a significant drop in capital expenditure for all the robots that used to put 70 parts together."
- markstos 6y ago
  From the internet: "assuming your joint is designed properly and you have an experienced welder performing the work, your welded joint will be as strong as the base materials it is joining." Welds are key to most bicycle frames and they are not known as the part that's likely to fail.
  - deelowe 6y ago
    The "weld is stronger than the base metal" argument is often repeated on the internet, but it's overly simplistic. Welded joints don't usually fail at the seam (a.k.a the weld). Instead, they fail near the seam where the base metal has been stressed due to thermal expansion/contraction and heat treating. It is correct that when done properly, everything should be fine, but I wouldn't trust the vast majority of body shops to have access to welders who would do it "properly."
    - glenstein 6y ago
      This doesn't make it any more clear whether weld repair poses a practical danger for most people in most circumstances. If it's the case that metal stress near the point of welding is the where it's more likely to fail, that still doesn't tell me how much more likely to fail. For all I know it could be the weakest part but still such a trivial difference as to pose no concern. And the point about welders leaves a dangling, open ended implication that invites anyone reading the sentence to just go ahead and assume that poor weld jobs leading to immenent danger are happening all the time. But are they? Or is that just being noted as a hypothetical possibility? I'm having a hard time telling whether a possible or probable danger is being asserted here.
      - jacquesm 6y ago
        Welding is like programming. Everybody with half a brain and some skills can weld. But proper welding is an art form, and the difference between the two levels is many years of work and study. So for most people welding like that is not in the cards, but a trained and meticulous professional can do miracles (or close to miracles). It starts to get really interesting when you start hanging stuff from your welds, for instance when building an overhead crane.
- Someone1234 6y ago
  The single-cast is only the aluminum. Several common vehicle glues are stronger than aluminum (e.g. Steel Reinforced Epoxy), and aluminum itself is not very strong. The safety critical structural elements of their cars are a mixture of mild and high strength steel[0]. [0] https://www.teslarati.com/tesla-model-3-body-structure-steel-aluminium-composition/ https://www.teslarati.com/tesla-model-3-body-structure-steel...
  - hwillis 6y ago
    A 2017 article is very out of date. The Model 3 rear subframe is cast aluminum: https://insideevs.com/news/408645/tesla-model-y-mega-casting-teardown-video/ https://insideevs.com/news/408645/tesla-model-y-mega-casting... Which is certainly a safety critical structural element. Additionally, glues are not stronger than aluminum. I don't know if you're thinking of a composite resin (eg glass fiber), but normal adhesives are weaker even than pure aluminum, which is ~5x weaker than all the commonly used (copper age-hardening) alloys of aluminum.
    - Someone1234 6y ago
      I have no interest in a pointless debate about the semantic difference between the passenger compartment Vs rear crumble zone and what "safety critical" means, no do I over the word "common" in "common vehicle glues." If you're going to read my post with the worst possible interpretation then try to correct that uncharitable reading, I just have no interest in a discussion.
      - hwillis 6y ago
        So basically you didn't look at the link, because the castings -which, again, are new- are part of the safety cell. They are not the rear extruded rails. If you had specified an adhesive when you first wrote the comment, sorry- I managed to not see it. I don't know of any "steel reinforced epoxy" besides JB weld (which generally should not be used on anything bigger than a lawnmower), but it and actual 3M vehicle adhesives[1] are a full 10x weaker in shear and 15-20x weaker in tension that plain boring 6061. [1]: https://multimedia.3m.com/mws/media/1467016O/07333-irsa-technical-data-sheet.pdf https://multimedia.3m.com/mws/media/1467016O/07333-irsa-tech...
- hwillis 6y ago
  They are not going to weld castings except maybe for very small cracks and even then it's very unlikely. The casting is not in a place that could be repaired if it were steel, though. It's the main structural member, located behind the rear seats. If you needed to weld there you'd need to take the car practically down to its frame. Even if it were in a place that was accessible and subject to repairable damage, you would not see it welded or cut. First off a lot of it isn't physically possible to weld; it's in very deep (6") pockets and you'd have a huge amount of difficulty getting penetration. Second, welding aluminum is not super easy. Anyone can weld steel, aluminum isn't the worst but it is much trickier. Third, aluminum welds create a weakness in the aluminum around the weld, because it gets hot but isn't properly tempered as it cools. It's still strong, but the loss is significant- temper is responsible for ~70% of the strength of common aluminum alloys. Fourth, the weld and the surrounding area are very weak (<40% strength) for several days after the repair. It's a huge pain in the ass and you probably can't just let somebody drive off on it.
Ottolay 6y ago
From my experience, if the frame of the vehicle is functionally damaged then the car often totaled anyway. Maybe that is not true for expensive cars like the Model Y.
- londons_explore 6y ago
  Stripping a car for parts will frequently earn you a lot of money. It isn't unreasonable to just disassemble the entire car and sell all the parts on the 2nd hand parts market and earn enough to buy a new similar car.
  - HumblyTossed 6y ago
    Are you allowed to sell a Tesla for parts?
    - gibolt 6y ago
      Why not? However, anything related to the battery/charging swapped out on the recipient Tesla may disable Supercharging.
    - netcan 6y ago
      Tesla parts are actually really valuable. A lot of people want their engines (and batteries) for hot rod projects, and there are very few around. They can't be bought new, and the used price is probably higher than new would be. I heard some irrational sounding numbers a few years back. Maybe prices have come down, now that more Teslas have had the opportunity to be totalled and sold for parts.
      - giancarlostoro 6y ago
        Makes you wonder if buying a Tesla to scrap for parts would be worthwhile at all.
        netcan 6y ago
justapassenger 6y ago
From experience - i3 frame means that during even small accident car gets totalled, as stress is moving across whole component and you have to rebuild basically whole car to make it safe again.
- rbanffy 6y ago
  True, but the i3 is not made of Aluminum, but composites which will have to be glued together in such way as not to compromise structural integrity. Also, the insurance will have that factored in and you should always consider it as part of the price of the car.

Aeolun 6y ago

It seems to me that cutting out, and welding or glueing in a new part had a serious effect on the structural integrity of the vehicle.

andrewmunsell 6y ago
I'm sure there's some cases where that might be true or it's not practical for other reasons (I'm not an automotive engineer or anything), but remember, the 3 has ~70 parts welded together for this same area of the car, so welds themselves are not fundamentally bad.
- thesimp 6y ago
  Just as the BMW i3 the Alfa Romeo 4C also has a carbon fiber monocoque: https://www.toraytac.com/media/story/XkKY/Alfa-Romeo-4C-Monocoque https://www.toraytac.com/media/story/XkKY/Alfa-Romeo-4C-Mono.... And Alfa Romeo has published a 162 page manual for bodyshops on how to do repairs. The PDF is out there in the internet for people that want to know the technical details.
- MaxikCZ 6y ago
  I dont think the main concern here is that the new part would be welded in. When the car is in design process, each weld is carefully calculated to provide the exact binding force at the precise location. In case of accident, the car is modeled to crumble just right to absorb maximum energy without compromising cabin space, thus protecting occupants. The process of cutting out and welding in parts almost always means altering the stiffness of such bonds (and/or moving the bonds to different locations), which can be very dangerous in the event of accident
gfody 6y ago
my thoughts as well, otherwise what was the point of casting it whole in the first place?
- andrewmunsell 6y ago
  The single casting for the Y is for cost an NVH reduction per the article & Elon. My early production Y has 4 pieces for the rear instead of the single one this new machine will produce, but it shouldn't be any structurally less sound
- TomVDB 6y ago
  All the remaining advantages that are mentioned in the article: cost, weight reduction -> increased autonomy, better handling and driving comfort.
- bronson 6y ago
  The point is: "We're moving to an aluminum casting instead of a series of stamped pieces. We'll go from 70 parts to 4, then 1 with a reduction in weight, improvement in [NVH], reduction in cost, and a significant drop in capital expenditure for all the robots that used to put 70 parts together."
markstos 6y ago
From the internet: "assuming your joint is designed properly and you have an experienced welder performing the work, your welded joint will be as strong as the base materials it is joining." Welds are key to most bicycle frames and they are not known as the part that's likely to fail.
- deelowe 6y ago
  The "weld is stronger than the base metal" argument is often repeated on the internet, but it's overly simplistic. Welded joints don't usually fail at the seam (a.k.a the weld). Instead, they fail near the seam where the base metal has been stressed due to thermal expansion/contraction and heat treating. It is correct that when done properly, everything should be fine, but I wouldn't trust the vast majority of body shops to have access to welders who would do it "properly."
  - glenstein 6y ago
    This doesn't make it any more clear whether weld repair poses a practical danger for most people in most circumstances. If it's the case that metal stress near the point of welding is the where it's more likely to fail, that still doesn't tell me how much more likely to fail. For all I know it could be the weakest part but still such a trivial difference as to pose no concern. And the point about welders leaves a dangling, open ended implication that invites anyone reading the sentence to just go ahead and assume that poor weld jobs leading to immenent danger are happening all the time. But are they? Or is that just being noted as a hypothetical possibility? I'm having a hard time telling whether a possible or probable danger is being asserted here.
    - jacquesm 6y ago
      Welding is like programming. Everybody with half a brain and some skills can weld. But proper welding is an art form, and the difference between the two levels is many years of work and study. So for most people welding like that is not in the cards, but a trained and meticulous professional can do miracles (or close to miracles). It starts to get really interesting when you start hanging stuff from your welds, for instance when building an overhead crane.
Someone1234 6y ago
The single-cast is only the aluminum. Several common vehicle glues are stronger than aluminum (e.g. Steel Reinforced Epoxy), and aluminum itself is not very strong. The safety critical structural elements of their cars are a mixture of mild and high strength steel[0]. [0] https://www.teslarati.com/tesla-model-3-body-structure-steel-aluminium-composition/ https://www.teslarati.com/tesla-model-3-body-structure-steel...
- hwillis 6y ago
  A 2017 article is very out of date. The Model 3 rear subframe is cast aluminum: https://insideevs.com/news/408645/tesla-model-y-mega-casting-teardown-video/ https://insideevs.com/news/408645/tesla-model-y-mega-casting... Which is certainly a safety critical structural element. Additionally, glues are not stronger than aluminum. I don't know if you're thinking of a composite resin (eg glass fiber), but normal adhesives are weaker even than pure aluminum, which is ~5x weaker than all the commonly used (copper age-hardening) alloys of aluminum.
  - Someone1234 6y ago
    I have no interest in a pointless debate about the semantic difference between the passenger compartment Vs rear crumble zone and what "safety critical" means, no do I over the word "common" in "common vehicle glues." If you're going to read my post with the worst possible interpretation then try to correct that uncharitable reading, I just have no interest in a discussion.
    - hwillis 6y ago
      So basically you didn't look at the link, because the castings -which, again, are new- are part of the safety cell. They are not the rear extruded rails. If you had specified an adhesive when you first wrote the comment, sorry- I managed to not see it. I don't know of any "steel reinforced epoxy" besides JB weld (which generally should not be used on anything bigger than a lawnmower), but it and actual 3M vehicle adhesives[1] are a full 10x weaker in shear and 15-20x weaker in tension that plain boring 6061. [1]: https://multimedia.3m.com/mws/media/1467016O/07333-irsa-technical-data-sheet.pdf https://multimedia.3m.com/mws/media/1467016O/07333-irsa-tech...
hwillis 6y ago
They are not going to weld castings except maybe for very small cracks and even then it's very unlikely. The casting is not in a place that could be repaired if it were steel, though. It's the main structural member, located behind the rear seats. If you needed to weld there you'd need to take the car practically down to its frame. Even if it were in a place that was accessible and subject to repairable damage, you would not see it welded or cut. First off a lot of it isn't physically possible to weld; it's in very deep (6") pockets and you'd have a huge amount of difficulty getting penetration. Second, welding aluminum is not super easy. Anyone can weld steel, aluminum isn't the worst but it is much trickier. Third, aluminum welds create a weakness in the aluminum around the weld, because it gets hot but isn't properly tempered as it cools. It's still strong, but the loss is significant- temper is responsible for ~70% of the strength of common aluminum alloys. Fourth, the weld and the surrounding area are very weak (<40% strength) for several days after the repair. It's a huge pain in the ass and you probably can't just let somebody drive off on it.

Ottolay 6y ago

From my experience, if the frame of the vehicle is functionally damaged then the car often totaled anyway. Maybe that is not true for expensive cars like the Model Y.

londons_explore 6y ago
Stripping a car for parts will frequently earn you a lot of money. It isn't unreasonable to just disassemble the entire car and sell all the parts on the 2nd hand parts market and earn enough to buy a new similar car.
- HumblyTossed 6y ago
  Are you allowed to sell a Tesla for parts?
  - gibolt 6y ago
    Why not? However, anything related to the battery/charging swapped out on the recipient Tesla may disable Supercharging.
  - netcan 6y ago
    Tesla parts are actually really valuable. A lot of people want their engines (and batteries) for hot rod projects, and there are very few around. They can't be bought new, and the used price is probably higher than new would be. I heard some irrational sounding numbers a few years back. Maybe prices have come down, now that more Teslas have had the opportunity to be totalled and sold for parts.
    - giancarlostoro 6y ago
      Makes you wonder if buying a Tesla to scrap for parts would be worthwhile at all.
      - netcan 6y ago

justapassenger 6y ago

From experience - i3 frame means that during even small accident car gets totalled, as stress is moving across whole component and you have to rebuild basically whole car to make it safe again.

rbanffy 6y ago
True, but the i3 is not made of Aluminum, but composites which will have to be glued together in such way as not to compromise structural integrity. Also, the insurance will have that factored in and you should always consider it as part of the price of the car.