this post was submitted on 26 Aug 2023
847 points (94.1% liked)
Technology
60079 readers
3336 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 2 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
10 micron (0.01mm) is pretty reasonable tolerance for a lot of stuff. The laminations in Tesla's motors will be held to somewhere around that, possibly even tighter. Things like motor winding insulation coatings will be far tighter.
For something like body panels or plastic interior pieces it's utter overkill and a waste of resources.
Something like a body panel is going to expand/contract a couple of orders of magnitude more than 10 microns just from the weather changing day-to-day.
It's pretty common for a CMM to be in its own climate controlled room. Parts will be placed in the room and allowed to reach reference temperature for a several hours prior to measurement.
On production lines you usually skip the absolute measurement of a CMM and use go/no-go gauges. One should fit, one should not. They'll be made of a material with similar thermal expansion coefficients as your parts. As long as they've both been sitting around for a while they'll be at the same temp. They'll have expanded or contracted the same amount from reference so their relationship of go/no-go will still hold true.
The whole field of metrology is a never ending rabbit hole - really interesting the more you get into it.