Tesla Fremont to Soon Activate World’s Largest Unibody Casting Machine
tesmanian.com
tesmanian.com
This article from the SAE (you know, the industry group of car building) is way more interesting.
Putting the 'hack' in hackernews, I suppose.
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-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.
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
Welds are key to most bicycle frames and they are not known as the part that's likely to fail.
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.
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.
Welding lifting rings onto stuff is not really a high bar. High quality welds are easy if the materials you're dealing with are easy. Stuff that is exotic, expensive and hard to work with is the stuff that takes real skill because it's really hard to get a ton of practice at those things (there's only so much magnesium alloy that needs welded) so you need a lot of skill and experience in varied circumstances to do a high quality job from the get go.
I can weld and I can dick around in a bash shell but I'm much better at the one that is my current day job that I do for ~40hr a week.
For "easy" material combinations you can get away with a surprising amount of corner cutting and still pass a bend test. Good welds aren't hard. A community college will have you passing a bend test on an overhead weld in a semester and doing the same for pipe in two but it will all be in steel and a limited variety of consumables and processes. Those kids might be masters of 7018 but hand them some aluminum electrodes and they'll be lost. Good welds the first or nearly the first time on material + consumable combo on which you only burn say 10lb a year is what really takes practice.
Once you do that though, it is actually true, and even then you may see stress cracks next to the weld if the change in thickness is too abrupt. You need to gradually thin down or you'll get a focal point for stresses.
Because of how thermally conductive it is it doesn't work the same way.
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...
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.
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.
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-tech...
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.
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.
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.
If you have a project car that really wants a tesla engine.. the car wants what the car wants. I wouldn't be surprised if some number of Teslas have been bought new to scrap.
It's always been legal to sell parts off your car. Do not buy anything that attempts to prevent you from owning what you bought through any sort of user agreement.
The car I did this to was totaled in Belgium, bought for the scrap value and repaired on a very small budget. It is still driving the streets of Bucharest today. The MOT inspectors could not find proof that the car had been worked on, which I took as a badge of honor until they went off on a tangent that therefore it must be a stolen re-id'd car. Then I showed them the step-by-step pictures and it was all good. Fun job!
It is also an open question on what it would cost to make this casting as a repair part.
Tesla is probably doing the same.
Remember a good number of repairs Tesla will end up paying for - through various warranty schemes - so they care about repairability too, just to a lesser extent than they care about product performance and cost.
He's actively against public transport (which is by far most ecological), pursuing dreams of living on Mars (which is unpractical on so many levels, that if it'll be ever complete, it'll be trip of lifetime to fifthly rich people), building expensive toy cars (car that does 0-60 in less than 6s? who would even want that?) and many more.
Boring company, aka, private tunnels for Model 3/S/X (https://electrek.co/2020/07/20/elon-musk-boring-company-tesl...)? It's as much of a public transportation as Uber.
Hyperloop, aka vaporware?
Teslas (especially the Model 3 and Y) are not inherently difficult to repair. The problem is that Tesla's restrictive policies make it difficult for individuals to access the documentation and parts to do so.
Thought experiment: Imagine that the overall material required is cut by 10-20% by tons of optimizations and reductions. That means the supply chain and associated energy/costs vanish. If you have a failure rate of less than that (probably much less) scrapping is likely still better.
Also dropping a broken car and building a new car takes manufacturing costs.
I'm not even sure there's a tradeoff here, since bending a frame of any car is bad news whether or not its one piece.
It's not unusual for mechanics to buy newly totaled cars at their salvage value as a convenient exit to the owner, and either rebuild the vehicle or part it out as a side hustle. A repaired salvage vehicle is eligible for a rebuilt title in some states.
With unibody cars, that doesn't work anymore. Body shops have frame racks to pull steel cars back into shape. That works if the car isn't too bent and your standards aren't too high.
Aluminum unibodies don't respond well to bending so yes... If the frame is tweaked enough to screw up the wheel track, that's probably the end of the car. Maybe find a flood car with a good frame and swap everything over. This is true whether the car's body is a single casting or built up by welding 70 pieces together.
I am curious how long they will go without changing the outward design of the 3 or Y. Most manufacturers find it necessary to iterate every few years to keep customers interested and show progress while Tesla shows progress mostly through features added OTA. They already have range numbers down for a significant lead covering a few years so they are not under the same pressure.
edit: This all goes back to Musk's question to engineers why can't a car be in as few pieces as possible using a matchbox/hot wheels car as example
I think the model Y is already massively simpler than the 3 is (from watching Sandy Monroe on YouTube), but whether it will be possible to perform such a modification to the 3 isn't clear. My suspicion is that there's to e much complication in that area of the car (rear suspension) to make a straight swap to the Y style of rear bodyshell section.
So for example the factory in Berlin will just start with a monster press like this on day 1, so all Model Y built there will automatically have the "new" design. Same for the Model 3 and Model Y lines in Texas.
Because then trivial accidents become major costly repairs and/or result in totaling of the vehicle.
There is an advantage of having separate body panels, support pillars, bumpers, etc. It can all be replaced separately.
The transcript is not great but you get the point:
“ It's like if you want to pay more for insurance, you can. But if you want to pay less, then please don't drive so crazy. Then people can make a choice. Like, OK, they want to drive aggressively.
In that case, it'll be higher insurance. Or they want more capital enter driving and pay less. This was actually very helpful for us to have a feedback loop to see what is driving insurance expense. A lot of it is just -- it's like a little fender bender and the net fender bender because of the way that the body collision repair is being done.
It costs like $15,000 or something crazy and like -- and then we can actually adjust the design of the car and adjust how the repair is done to actually have the fundamental cost of solving that problem would be less.So this has helped us under a whole bunch of facility things that we were doing basically without realizing it. But this is a problem with -- in general, with insurance is like if the insurance is, like, all you can eat, then the feedback loop for improvement is sweet. So this gives us a great feedback for improvement because it's basically a fundamentally better insurance product. I'd also like to say, I'm inspired of recruiting because if there's one thing I'd like to come out of this call, it's that a lot of great people want to join Tesla.”
https://www.fool.com/earnings/call-transcripts/2020/07/23/te...
Perhaps that was foolish in hindsight, since most of their quality, workmanship and repairability problems stem directly from having to learn (through trail-and-error) all the same things the other manufactures learned long ago.
The parallels with McDonalds taking Chipotle under their wing to teach supply chain management, distribution, food safety and more are undeniable. Chipotle's founders famously scoffed at learning _anything_ from McDonalds... which may have resulted in the numerous food safety handling issues they had a few years back (not washing raw produce that was transported through multiple handling facilities and then into stores), and legendary portion control variance (totally depends who makes your burrito... it may weigh a 1/2 lb, or 2lbs... a total coin flip).
It's difficult to scale these complex organizations - why make it harder on yourself? Learn from other people's mistakes and try not to repeat them.
foisting large insurance bills onto Tesla customers because Tesla couldn't design their car to be repairable, even by Tesla themselves - doesn't seem fair either.
Until then, repairability of your expensive Tesla is a concern.
Swapping dies takes a few hours. Making new dies takes many months and costs some fraction of a million dollars.
> I am curious how long they will go without changing the outward design of the 3 or Y.
I really hope they make a car that looks different soon. Branding is just SO deeply engrained in the car industry; I think they're damaged by people considering the S and 3 basically exchangeable. They should really have different styling just to make people feel like they have more than one option in buying a Tesla. It makes the number of competing non-Tesla choices seem twice as large.
The Cybertruck definitely looks different.
I'm thinking more about things like the roadster. Even for being relatively similar, the accents are all more aggressive and it creates a very distinct look that the 3XY absolutely do not. And then the most frustrating thing is that Musk clearly does not intend to make very many of them! He's treating it like an ultra halo car, when just having a convertible version of the 3 with a slightly different body would make the psychological choice to buy a Tesla far easier.
Like, people don't even have to buy it. Just by existing it would make Tesla look more competitive- it just needs to seem like an accessible choice. The roadster would be perfect, but it's too expensive and full of unnecessary shit for no reason, and that totally ruins the benefit! It epitomizes what frustrates me with Musk- a great core idea, but deeply crippled by goofy whims.
I don't buy that the only disadvantage is the increase repair cost of the car in case if accident.
Teslas RD budget is tiny, given for much stuff they do in-house - designing cars, autopilot, seats, batteries, robots, solar panel, solar roof, and many others. Their RD is roughly on the level of Mazda, which does much less stuff in-house.
> None of the carmakers do R+D on basic materials and are limited by the commercially available alloy formulas
You really believe that companies that spend billions of dollars per year on basic materials, that are some of the most important for their products, just look at the prodcut catalogue from suppliers and order from there?
That is pretty close to what they do. Modern car companies mostly do integration and final assembly along with some marketing and finance. Vertical integration in the American auto industry died with Henry Ford until Tesla revived it. You could argue that Toyota is somewhat vertically integrated with the cross holdings they have in some of their Japanese suppliers.
Citation needed. What has Tesla been able to accomplish with its inhouse R&D that nobody else has? Other than battery design (using cells developed and manufactured by Panasonic), pretty much everything Tesla does is subpar compared to automobile industry standards.
May I know what is the basis for those claims? As someone who works in the field, I feel very curious to know where you got such a wrong impression.
Materials research has been constantly reducing car weight for decades, at the same time that safety was improved and production costs reduced. New aluminum and steels are developed every day.
For example, the development of high strength steels have been driven by the automotive industry. The contribution of Tesla is merely anecdotic at this point.
If you believe that I have a bridge to sell you...
Pretty much every traditional automaker spent more on R&D last year than Tesla made.
Carmakers have tried unibody frames in the past, and they abandoned them pretty quickly because they're expensive to repair in the event of even minor accidents. (This is also why nobody else does shell cars like the Cybertruck anymore; because any damage to the shell can cause a structural weakness that would require the entire shell be replaced to make the car legally roadworthy.)
With multi-part frames, individual parts of the frame can be made of different materials and stiffnesses based on the physics or safety requirements imposed on that part of the frame. This means that the overall frame can be both stronger and lighter. With a unibody frame, you have to use the same material through the frame, and the only way to adjust stiffness in any part is to control the amount of material used.
These kinds of castings are relatively new, and car companies are surprisingly unwilling to spende more than low millions on moonshot tech. It was not an insignificant gamble by Tesla.
Automotive companies utilize a myriad of frame designs for their vehicles - each one a collection of different alloys, structural shapes and castings depending on the design goals for not only the vehicle of today, but changes that they foresee in future vehicles that would utilize the same basic BIW lines (to conserve capital expenditures, training procedures and inspection methodologies).
There are some automotive companies that rely on some cast product of various sizes in their frame designs. That is not really new.
Tesla is obviously taking some more extreme measures than other automakers, but electric vehicles do inherently put more frame design freedom on the table given that there is not an engine compartment per se to consider in terms of passenger safety.
That said, generally, the disadvantages of large castings in automotive applications are:
1. Poor reparability, and
2. Porosity risks (which can unexpectedly yield structural issues), and
3. Wide tolerances, and
4. Need for a post-cast finished machining process (application dependent), and
5. Long cycle times, and
6. Design space difficulty in managing the weight/strength tradeoff and crumble zone development (application dependent).
Keep in mind that while a casting process may seem simpler that "traditional" BIW lines, those traditional lines are highly optimized and generally very efficient and flexible (often running multiple different kind of frames over a single line) - typically employing above 95% automation. I know Tesla has struggled with their BIW lines in the past in terms of quality. I am not sure of Tesla's current situation having not really followed Tesla's process for a number of months.
The advantage, I suppose, that Tesla is seeing is that they can radically simplify their BIW line.
Those cars aren't generally sold outside of China due to their failure to meet international safety standards.
Also, I'm not convinced the reason smaller cars don't come to the US is due to safety issues since they exist in Europe where there are similar safety standards.
Tesla and SpaceX share a few employees in this space actually.
So the guy who led the materials research that resulted in the infamous bending iPhone is Tesla's chief scientist on this project?
Not promising, though on the other hand cars are supposed to bend and flex in the event of an accident...
Production method matters a ton in steel, where a LOT of strength comes from the way the metal was formed, and is only fully lost when the steel is near melting temperature. Alloy steels don't care so much how they were formed, but they're usually too expensive.
Aluminum is different, and cast parts can be very strong if they're heat treated properly. The most common aluminum alloys (pure aluminum is nearly useless) are made with copper. Copper causes smaller grains to form as aluminum solidifies, and then over time it precipitates out from the bulk material and ends up in the borders between grains of purer aluminum. When stress attempts to pull grains past each other, the copper atoms act like wedges and keep everything from moving.
Because the copper creates the grain shape itself, you don't need to work aluminum alloys to make them strong. Aluminum is semi-noteworthy (but far from unique) in that it loses strength very quickly when worked. You need to change a bunch of alloying elements to control for shrinkage (or at least delay until the part can be ejected from the mould), viscosity, temperature, oxygen tolerance etc. but I don't know much about all that. I know cast alloys are weaker than the strongest extruded alloys, but not by that much. There aren't problems with brittleness etc like you can get with steel.
Also note that "cast iron" is a metal in its own right, and is NOT just steel/iron that has been cast. Cast iron is the highest-carbon (1-3%) alloy of steel, and that is what makes it weak and brittle- not the fact that it's cast. That much carbon causes a bunch of ceramic and graphitic phases to form all kinds of weird (but extremely cool, metallurgically) garbage.
Sandy Munro (and others) have advocated larger castings for ages. Watch munrolive, autoline and other youtube podcast interviews for ongoing analysis and discussion.
The community interest in unibottle, multivalve (name?), simplified wiring harnesses, large form unicasting, and all the other deepdive innovations is really gratifying. There's been such a huge backlog and now the dam is bursting.
Whatever else I think about Tesla and Elon Musk, this really feels like a sea change.
Octovalve, here's a good video on it:
No wonder insurance rates are that high.
I got hit in my old Corolla, bill (for insurance) was $4500. $3000 of that was the paint job.
It's insane, it's costs nearly $100 more per-term to have full coverage on my 2018 Model 3 than it does for the same coverage on my 2015 Leaf. Outrageous!
How would it compare with a few laser sinterers? I expect the initial investment would be bigger, especially as these machines are slower, so more would be required. But then, sinterers are probably a lot more versatile, could produce the whole 70 parts plus the rivets holding them at once, or a few single replacement parts. Probably with less wasted material?
Curios -- could the whole body be cast?