1y ago

Leaked Email Shows Elon Musk Demanding "Sub 10 Micron Accuracy” Cybertruck Parts

jalopnik.com Leaked Email Shows Elon Musk Demanding "Sub 10 Micron Accuracy” Cybertruck Parts

Tesla is facing issues with the bare metal construction of the Cybertruck, which Elon Musk warned was as tricky to do as making Lego bricks

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to build it to that accuracy the car would have to cost millions
- To build it with that accuracy would be physically impossible. Guess he forgot about thermal expansion and contraction. Guess he forgot about the weather...
  
  I mean, it says cybertruck parts, not the whole thing including assembly. Certainly possible for some manufacturing processes under given conditions to produce parts with ±0.005 tolerances like laser cutting or precision CNC machining of small dimensions. But it's obviously completely unrealistic given that most parts for a car will be of large-ish dimensions and stamped, injection molded, cast, forged, extruded... none of which lends itself to IT grades better than 10, far away from talking about microns.
  
  Didn't you see what musk said about legos and pop cans? It can be done, the tronk just needs to be built out of legos and pop cans, duh!
  
  A rumor I've heard somewhere online is that people are noticing the body panels wobbling, or 'breathing' in and out in the wind. Not sure how true that is, I can't find a video showing this happening, but it does make sense. Even the most subtle flexing of a shiny flat surface becomes way more obvious and sticks out like a sore thumb.
  
  Musk is a scammer who has almost no practical understanding of engineering.
  He (and unfortunately many after him) forgot about thermal expansion and contraction as well with his dumbass Hyperloop idea. Have a hermetically sealed metal tube with a vacuum run exposed for 200km and let's just ignore thermal expansion. One station would have to move left and right for several meters throughout the day, every day for that, the 200km pipe somehow would need to be able to move about... His "designs" and "ideas" are engineering nightmares
  
  Nah, not impossible people build stellarator type Fusion reactors with large freeform metal parts in that tolerance region that are exposed to liquid helium.
  
  Does not change the fact that all materials expand when temperature rises and contract when temperature cools. Plus different materials have different temperature expansion coefficients.
  
  Most. Water, for example, takes up more volume in spaces when frozen
  
  True, water is weird like that.
  
  So does the stellarator. What's the argument here?
  
  just define a temperature :D
- Indeed, that's about 10 to 100 times more accuracy than other automakers. Those tolerances just aren't necessary so no supplier is going to have the tools or infrastructure in place to make parts to such a high degree. Body shop alone sees fluctuations in millimeters because industrial robots can't do any better than half millimeter accuracy, if they're brand new.
  
  If you can even get something like +/-3 or 4 mm with say a cpk of 1,33 you are doing pretty well for a whole body.
  It's probably a pr stunt. If this is real then they are doomed because they have not yet understood that you need to compensate tolerances and design a robust assembly that can handle this. If you are trying to get crazy high part precision you have not understood how big scale manufacturing works. This is why the Japanese are often so highly regarded in this and might be the true art of car (or large scale) engineering.

355 comments