254
10 microns = .01 mm = .0004 inch
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 24 Aug 2023
254 points (100.0% liked)
the_dunk_tank
15866 readers
561 users here now
It's the dunk tank.
This is where you come to post big-brained hot takes by chuds, libs, or even fellow leftists, and tear them to itty-bitty pieces with precision dunkstrikes.
Rule 1: All posts must include links to the subject matter, and no identifying information should be redacted.
Rule 2: If your source is a reactionary website, please use archive.is instead of linking directly.
Rule 3: No sectarianism.
Rule 4: TERF/SWERFs Not Welcome
Rule 5: No ableism of any kind (that includes stuff like libt*rd)
Rule 6: Do not post fellow hexbears.
Rule 7: Do not individually target other instances' admins or moderators.
Rule 8: The subject of a post cannot be low hanging fruit, that is comments/posts made by a private person that have low amount of upvotes/likes/views. Comments/Posts made on other instances that are accessible from hexbear are an exception to this. Posts that do not meet this requirement can be posted to !shitreactionariessay@lemmygrad.ml
Rule 9: if you post ironic rage bait im going to make a personal visit to your house to make sure you never make this mistake again
founded 4 years ago
MODERATORS
I used to work for a company that made stamping dies for aluminum cans, and some of those dies had tolerances close to .0004", because the aluminum is very thin and could crack and tear if the dies were not made precisely. The cans themselves are not that precise, they just need to hold beer without exploding. I can't speak to Legos, but cars absolutely do not need this kind of precision, not even in the bearings. And especially not in the sheet metal body panels.
Tolerances depend on the function of the part and are selected to balance various tradeoffs in production costs and assembly. A well engineered design does not require tight tolerances for the vast majority of features (reducing scrap, tooling, and labor costs), but some specific mechanism components like gears and driveshafts demand very tight tolerances for profile and runout in order to function reliably.
Tolerances will often influence which type of machine tool is used to produce a feature. A tight tolerances on an outside diameter might make the difference between a part being made on a lathe in one/two operations, or requiring additional operations on a cyllendrical grinder. Overzealous requirements for surface finish will require slower feedrates, sharper tools (which wear more quickly) and extend cycle times significantly, or require extensive manual hand-finishing.
Commercial bearings routinely have tolerances of 0.0004" or less & performance bearings designed for specific aerospace use/applications can have substantially tighter tolerances.
Legos famously have a weirdly high tolerance for injected molded plastic*, it's part of the branding they use to justify their high price. It does make them snap together more reliably than Mega Blocks or whatever, but Mega Blocks or whatever usually snap together anyway, so I don't know whether that extra precision counts as necessary.
* People quote all sorts of tolerances for this, but the most credible-looking one I found was 0.04 mm.
within 10 micrometers apparently
Legos company profile page 20 specifies that they must have tolerances within 10 micrometers
I assume. It was quoted on Wikipedia, but I can't be assed to look thru it myself. The pdf is linked if you want to