Comment by layer8
1 day ago
To be fair, half a millimeter isn’t even that much precision, generally speaking. You wouldn’t be anywhere close to manufacturing a working ball pen at that precision. Or even an acceptable keyboard, if we stay with plastic. With fans blades, the difficulty is probably the precision relative to the fan diameter.
The difficulty is clearance between two moving parts, with blades that deform slightly due to air pressure (at different amounts for different speeds) and with thermal expansion.
That’s not what the article says, they relate it to reproducibility of the manufacturing process: “Achieving such small tip clearances is essentially at the absolute limit of what injection moulding can consistently reproduce”. Though maybe they misphrased that, as for example Lego pieces have significantly smaller tolerances and are also manufactured using injection molding.
Clearance vs tolerance is important. Clearance includes all of the things I said.
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