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Comment by bitwize | Hacker News Reader

This is exactly the same problem of "mechanical engineers' job is to design parts, not machine them, so we'll take training on machines out of the mech eng curriculum." Result: fresh mech eng grads do not know how to properly design parts because they have no idea how they are machined.

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Should ontogeny recapitulate phylogony in the trades? Ie, should we teach historical techniques and graduate to modernity?

How do they solve this for mechanical engineering? Or is it an ongoing problem?

I don't know if they've addressed it. But ~15 years ago, my father was mentoring some college students and noticed that while they had been taught to machine a block (i.e., the rudiments of machining), they had no idea how to design appropriate tolerances for e.g., a gear because they hadn't ever made anything that complicated. So it was an issue back then. Presumably these details are learned on the job through trial and error, or by oversight from a more senior engineer who understands the requirements better. But in the past it was understood you'd start learning them from actually building parts as part of the curriculum.

A mate of mine was trained as a mechanical engineer and part of his training was to hand-file a chunk of steel to a cube exactly 2cm x 2cm, to within 1/10mm tolerance, every side exactly square. He said it was really, really, boring, but taught valuable lessons. I get this idea ;)

I would think that these days all of this is incorporated into the CAD/CAM software that they're using, right?

Vertical integration is valuable at many different scales

Surely they're made on CNC machines now? (well, since the 1970s)

Doesn’t matter, if you ask for physically impossible features to cut this is something you could technically do. Or you ask for a feature that adds multiple setups to an otherwise simple part and makes it wildly expensive

The CNC doesn't know either. What usually happens is that an engineer at the CNC shop figures it out for you.

Knowing some machining still lets you design parts and assemblies that are some combination of cheaper, better, etc. This is noticeable with precision or high performance assemblies. And how many revisions are needed.

Lathe, mill, CNC, or matter transmuter, doesn't matter. Effective design only becomes possible with intimate knowledge of how it is built.

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