Comment by jfoutz | Hacker News Reader

Comment by jfoutz | Hacker News Reader

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These are excellent points.

I think, these are sort of problems after you "level up". Lasers and 3d printers both have pretty light toolheads and no resistance. So you can get away with being pretty half assed with your stepper control, and still get results.

You're not wrong. But there's a big mountain of stuff to learn when starting with CNC stuff. Getting a cheap machine, figuring it out, tinkering with it, improving repeatability, these things are all part of how you get better. This is sort of a hobbyist diy mindset. Even if it's not a very good machine, you can still get results out of fusion360, or scad or whatever toolchain you work through.

Now, you're absolutely right, if you've got some cash burning a hole in your pocket, you can skip a lot of that machine tinkering hassle. pro level gear is absolutely magical. I'm more of a dabbler kinda guy, try it out, learn about it, if it seems cool 10x my investment in the hobby.

Anybody who wants to turn a laser cutter into a business is going to know all the stuff you've addressed. A hobbyist, they're going to need to not die from toxic gas from tanned leather. they're going to need to work out if they want to make stuff or if they want to tinker with the machine (both are totally valid).

To be super clear, I agree with all of your points. And it would be good to indicate the suffering you'll go through with a cheap machine. But, I'd argue a cheap machine can still be really fun. It all depends on what you're after.

It's all about the work piece. If you have that kind of requirement you most likely aren't going to be making it out of wood anyway, after all wood is an organic material and things like moisture content and temperature and moisture related shrinkage and expansion are going to undo pretty much all of your efforts to achieve 100ths of mm worth of precision. It would cost a fortune and you'd end up with workpieces that are no better than what these cheap machines produce. If you were to improve on this I'd invest in a better laser head long before I'd start to worry about the final bits of precision because for that you are using the wrong material to begin with.

Woodwork to within 0.1 mm is insanely precise. You won't be making watches with this, but a mechanical clock with wooden gears is well within the realm of the possible and your accuracy will be much better than that of the best woodworker using non-CNC tooling.

I thought of an analogy a moment ago, and I want to use it.

Drag racing has a super stock category, which is pretty much a normal car you buy and then mess with. Some folks are sponsored, but generally sponsorships are in the thousands of dollars range, not the millions, like pro funny car or top fuel would have. Most of the budget comes from folk's wallets and maybe winnings.

There are race car drivers, there are race car mechanics, and sometimes they're both the same person. Any _good_ driver is going to have some idea about how to turn a wrench. Any _good_ mechanic is going to have taken a few runs, and the fear of death rules out that particular career choice.

I think your point about the material is a good one. I think, that might also be a "level 2" skill. I think there is a huge amount of stuff to do to get a real sense of what CNC can do, and what a given person is able to do with a given setup. super beginner stuff like, what do I click to make the run go? is it connected right? What's a spline? Why is the enclosure orange? Just the safety stuff alone is pretty intense. And like, engaging the safety squint isn't going to help at all.

I'm very much an advocate for getting the shitty version to learn on. Maybe I learn bad practices, but I find I REALLY appreciate good tools. I have the tools I have because I finally understood what I needed and why it needed to be that way. Some of the tools in the box rarely get touched, but they're good enough when I need them.

Sorry to ramble at you, I guess I just needed to get that out.

_edit_

and of course, you're the author of the article. Ahh, it's been a rough week. I think it's a good intro.

All of this makes perfect sense. The markets these machines unlock simply didn't exist before and suddenly you find you can have capabilities in-house that would have cost you an arm, a leg and your firstborn not all that long ago.

As for the shitty version: it actually isn't all that shitty! Of course I'd like a larger bed and of course I'd like a more powerful laser. I'd like to be able to cut through two inches of steel with zero kerf. But in practice this is what I have and the easy solution is not to pine for the tool that you can imagine but to get the most out of the tool that you can afford and that you have.

youtube channel w&m levsha seems to show success cutting some metals with a cheap laser engraver by first oxidizing the surface black, then somehow lasering it off, and repeating the process a mind-boggling number of times to cut all the way through a thin sheet. is that a thing you have tried? what obstacles did you hit?

for example in https://youtu.be/PAFBkgawH3w?t=2m10s he says he cut through a razor blade in 600 passes

Interesting, but not very practical, if I need to cut metal I'll use an appropriate tool. But on the persistence level high marks for that effort!

the advantage from my point of view is that you can cut the metal to an arbitrary shape, which no other tool can (though edm and ecm can, and in that video he mentions 'etching' as an alternative, by which i suppose he means photolithography). in this case he isn't really taking advantage of that power

Etching is remarkably precise and efficient, I've made 100's of small parts in one run, for very thin metal it would definitely be my process of choice.

EDM can do it too but it will be super slow.

yeah, and i don't have a home ecm setup yet

i think it's common for tsmc to make hundreds of billions of small parts in one run with etching

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