Well, I seem to be talking to someone who knows more about alloys than I do.
Maybe. But what I know tends to be very patchy, depending on what rabbit holes I happen to have gone down at various times.
I figure there’s a need for Neodymium Iron Boron, for motor cores,
I hadn’t thought about magnetics at all, or anything exotic. I was just talking about basic steel.
Unless I’m mixed up, NdFeB is for permanent magnets. You might not need any permanent magnets. If you do, I believe also you need a big solenoid, possibly in an oven, to magnetize them. Said solenoid needs a metric butt-ton of current when it’s on, by the way, although it probably doesn’t have to be on for long.
Inductor and electromagnet cores, including for motors, are made out of “electrical steel”, which is typically cut to shape in thin plates, then laminated with some kind of lacquer or something for insulation against eddy currents. You can also use sintered ferrite powders, which come in a bewildering array of formulations, but if you’re just worried about motors, you’d probably only really need one or two.
Those plates are an example of a generalized issue, by the way. I think those plates are probably normally hot die cut in a roll process. In fact, I suspect they’re normally made in a plant that can immediately drop the offcuts, probably still hot to save energy on reheating them, into equipment that rerolls them back into more stock. Or maybe they even roll them out in their final shapes directly from a melt somehow.
You could mill every single plate in a motor core out of sheet stock on a milling machine… but it would take eternity, go through a ton of tooling, and generate a lot of waste (probably in the form of oily swarf mixed in with oily swarf of every other thing you process in the shop).
There are lots of processes like that, where stuff that you could “hand make” with the “mother machines” isn’t made that way in practice, because specialized machines, often colocated with other specialized machines in large specialized plants, are qualitatively more efficient in terms of time, energy, waste, consumables, you name it. Stuff that’s hot is kept hot until it needs to be cool (and often you try to cool it by putting as much as possible of the heat back into an input stream). Steps are colocated to avoid reheats. Waste products are recycled or used for something else, and the plant for “something else” is often also colocated.
It’s really hard to compete with that kind of efficiency. Most of the individual specialized machines are a lot more than a cubic meter, too. You already mentioned that temperature-sensitive processes tend to have optimal sizes, which are often really big.
Can you afford to use 10 times the energy and produce 10 times the waste of “traditional” processes? If not, you may need a lot of specialized equipment, more than you could fit in a reasonable-sized self-replicating module.
Cast Iron in the form of near-net-shape castings for machine frames,
All castings are imported, right?
By the way, you need nichrome or Kanthal or something like that for the heating elements in your furnace. Which isn’t really different from the copper wire you use, but it’s another item.
some kind of hardenable tool steel for everything else.
Here I break down. I suspect, but do not know, that if you only think in terms of making usable parts, you could at least get away only with “mild steel”, “alloy steel”, “tool steel”, and perhaps “spring steel”. Or maybe with only three or even two of those. I could be wrong, though, because there are tons of weird issues when you start to think about the actual stresses a part will experience and the environment it’ll be in.
If you do want to reduce the number of alloys to the absolute minimum, you probably also have to be able to be very sophisticated about your heat treating. I’d be pretty shocked, for instance, if a high-quality bearing ball is actually in the same condition all the way through. You’d want to be able to case-harden things and carburize things and do other stuff I don’t even know about. And, by the way, where are you quenching the stuff?
Even if you can use ingenuity to only absolutely need a relatively small number of alloys, on a similar theme to what I said above, there’s efficiency to worry about. The reason there are so many standard alloys isn’t necessarily that you can’t substitute X for Y, but that X costs three or four or ten times as much as Y for the specific application that Y is optimized for. Costs come from the ingredients, from their purification, from their processing when the alloy is formulated, and from post-processing (how hard is the stuff on your tooling, how much wear and tear does it put on the heating elements in your furnace, how much energy do you use, how much coolant do you go through, etc).
As I describe in my first reply to Jackson Wagner above, I can tolerate some inefficiency, as long as I stay above Soviet-style negative productivity. The goal is minimum reproduction time. Once I’ve scaled up, I can build a rolling mill if needed.
You could mill every single plate in a motor core out of sheet stock on a milling machine...
As you point out, that would be madness. I’ve got a sheet rolling machine listed, so I assume I can take plate and cold-roll it into sheet. Or heat the plate and hot-roll it if need be. The sheets are only a meter long and a few centimeters wide, so the rolling machine fits inside. They function like shingles for building the outside enclosure, and for various machine guards internally, so they don’t have to be big.
where are you quenching the stuff?
I’m quenching in a jar of used lubricant. Or fresh oil, if need be. 6% of the input is oil.
alloys isn’t necessarily that you can’t substitute X for Y, but that X costs three or four or ten times as much as Y for the specific application that Y is optimized for.
I’m a little reluctant to introduce this kind of evidence, but I’ve seen lots of machinist videos where they say “I pulled this out of the scrap bin, not sure what it is, but lets use it for this mandrel” (or whatever). And then it works fine. I am happy to believe that different alloys differ by tens of percent in their characteristics, and that getting the right alloy is an important occupation for real engineers. I just don’t think that many thousands of them all vary by “three or four or ten times.” I think I can get away with six or so.
Maybe. But what I know tends to be very patchy, depending on what rabbit holes I happen to have gone down at various times.
I hadn’t thought about magnetics at all, or anything exotic. I was just talking about basic steel.
Unless I’m mixed up, NdFeB is for permanent magnets. You might not need any permanent magnets. If you do, I believe also you need a big solenoid, possibly in an oven, to magnetize them. Said solenoid needs a metric butt-ton of current when it’s on, by the way, although it probably doesn’t have to be on for long.
Inductor and electromagnet cores, including for motors, are made out of “electrical steel”, which is typically cut to shape in thin plates, then laminated with some kind of lacquer or something for insulation against eddy currents. You can also use sintered ferrite powders, which come in a bewildering array of formulations, but if you’re just worried about motors, you’d probably only really need one or two.
Those plates are an example of a generalized issue, by the way. I think those plates are probably normally hot die cut in a roll process. In fact, I suspect they’re normally made in a plant that can immediately drop the offcuts, probably still hot to save energy on reheating them, into equipment that rerolls them back into more stock. Or maybe they even roll them out in their final shapes directly from a melt somehow.
You could mill every single plate in a motor core out of sheet stock on a milling machine… but it would take eternity, go through a ton of tooling, and generate a lot of waste (probably in the form of oily swarf mixed in with oily swarf of every other thing you process in the shop).
There are lots of processes like that, where stuff that you could “hand make” with the “mother machines” isn’t made that way in practice, because specialized machines, often colocated with other specialized machines in large specialized plants, are qualitatively more efficient in terms of time, energy, waste, consumables, you name it. Stuff that’s hot is kept hot until it needs to be cool (and often you try to cool it by putting as much as possible of the heat back into an input stream). Steps are colocated to avoid reheats. Waste products are recycled or used for something else, and the plant for “something else” is often also colocated.
It’s really hard to compete with that kind of efficiency. Most of the individual specialized machines are a lot more than a cubic meter, too. You already mentioned that temperature-sensitive processes tend to have optimal sizes, which are often really big.
Can you afford to use 10 times the energy and produce 10 times the waste of “traditional” processes? If not, you may need a lot of specialized equipment, more than you could fit in a reasonable-sized self-replicating module.
All castings are imported, right?
By the way, you need nichrome or Kanthal or something like that for the heating elements in your furnace. Which isn’t really different from the copper wire you use, but it’s another item.
Here I break down. I suspect, but do not know, that if you only think in terms of making usable parts, you could at least get away only with “mild steel”, “alloy steel”, “tool steel”, and perhaps “spring steel”. Or maybe with only three or even two of those. I could be wrong, though, because there are tons of weird issues when you start to think about the actual stresses a part will experience and the environment it’ll be in.
If you do want to reduce the number of alloys to the absolute minimum, you probably also have to be able to be very sophisticated about your heat treating. I’d be pretty shocked, for instance, if a high-quality bearing ball is actually in the same condition all the way through. You’d want to be able to case-harden things and carburize things and do other stuff I don’t even know about. And, by the way, where are you quenching the stuff?
Even if you can use ingenuity to only absolutely need a relatively small number of alloys, on a similar theme to what I said above, there’s efficiency to worry about. The reason there are so many standard alloys isn’t necessarily that you can’t substitute X for Y, but that X costs three or four or ten times as much as Y for the specific application that Y is optimized for. Costs come from the ingredients, from their purification, from their processing when the alloy is formulated, and from post-processing (how hard is the stuff on your tooling, how much wear and tear does it put on the heating elements in your furnace, how much energy do you use, how much coolant do you go through, etc).
As I describe in my first reply to Jackson Wagner above, I can tolerate some inefficiency, as long as I stay above Soviet-style negative productivity. The goal is minimum reproduction time. Once I’ve scaled up, I can build a rolling mill if needed.
As you point out, that would be madness. I’ve got a sheet rolling machine listed, so I assume I can take plate and cold-roll it into sheet. Or heat the plate and hot-roll it if need be. The sheets are only a meter long and a few centimeters wide, so the rolling machine fits inside. They function like shingles for building the outside enclosure, and for various machine guards internally, so they don’t have to be big.
I’m quenching in a jar of used lubricant. Or fresh oil, if need be. 6% of the input is oil.
I’m a little reluctant to introduce this kind of evidence, but I’ve seen lots of machinist videos where they say “I pulled this out of the scrap bin, not sure what it is, but lets use it for this mandrel” (or whatever). And then it works fine. I am happy to believe that different alloys differ by tens of percent in their characteristics, and that getting the right alloy is an important occupation for real engineers. I just don’t think that many thousands of them all vary by “three or four or ten times.” I think I can get away with six or so.