852
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
this post was submitted on 26 Aug 2023
852 points (94.1% liked)
Technology
59381 readers
1146 users here now
This is a most excellent place for technology news and articles.
Our Rules
- Follow the lemmy.world rules.
- Only tech related content.
- Be excellent to each another!
- Mod approved content bots can post up to 10 articles per day.
- Threads asking for personal tech support may be deleted.
- Politics threads may be removed.
- No memes allowed as posts, OK to post as comments.
- Only approved bots from the list below, to ask if your bot can be added please contact us.
- Check for duplicates before posting, duplicates may be removed
Approved Bots
founded 1 year ago
MODERATORS
LOL
Yeah ok.
Tell me you know nothing about manufacturing, without telling me you know nothing about manufacturing.
That one quote - assuming it is accurate - explains that Musk is even more of an idiot than everyone already knew he was. You don't make things at those tight tolerances. A couple of dimensions on a part might be (for instance the bore on a press fit sleeve), but you'd almost never, ever hold an entire part to that tight of a tolerance.
In imperial units, 10 microns is .00039". A human hair is roughly .001 to .005" thick. So he is asking for a tolerance that is 3 to 10x smaller than the thickness of a human hair. To put the absurdity of Musk's demand into perspective, most parts that go into a car are roughly an order of magnitude looser in tolerance with some dimensions being 2 orders of magnitude looser.
That difference might not sound like a lot, but holding something to +/-.0039 versus +/-.00039" could easily triple the price of an item or more. Easy. You use a tight tolerance only when you need to - that's engineering 101. Some parts could easily be +/- .039" and not affect their performance on bit. Close tolerance engine parts might be held at what Musk is demanding, but never "ALL PARTS" would be held to that.
As someone who knows almost nothing about the topic, wouldn't some (most?) of these parts be big enough that a small change in temperature or air pressure alone would cause these parts to expand/shrink enough to go over the tolerance limit?
Yes, and different materials will have different rates of thermal expansion. That's probably why the pixel 7 camera glass was cracking for no apparent reason when winter hit. Imagine coming out in the morning and finding all the glass in your car shattered because it got cold overnight. Or even worse you take it out of a heated garage on a cold day and the glass shatters while you're driving.