5 ms·

And you thought chatgpt was bad with subtle bugs in generated Python code. Now just imagine it scrapping a thirteen hour part or crashing a $300,000 machine.

CoastalCoder 4y ago
I've never worked with a CNC. Wouldn't they typically have safeguards against machine-damaging instructions?
- deleted 4y ago
  [deleted]
- jaipilot747 4y ago
  Usually not. Especially not in machines where you manually set the bits and the machine has no idea of the bit and it's properties, nor of the piece you are machining.
- Blackthorn 4y ago
  What the machine knows: (1) Where the head is. (2) If you program it right, where the end of the tool is. (3) If you program it right, what the width of the cutting edge of the tool is. That's it. You could maybe prevent it from diving the tool into the table. But you won't prevent it from trying to take a 2" cut into D2 steel. Or going down into a pocket and crashing the tool holder into a section of the workpiece. Or going down into a pocket and rapid moving left, slamming the tool into the workpiece (which if you're lucky will just break the tool).
  - mauvehaus 4y ago
    ... And depending on whether it uses steppers or servos, it may only know where the head is relative to where it was last told its origin was. ... And, if it's using steppers, it only knows that much if it hasn't slipped/missed/lost a step.
- davemp 4y ago
  From my at a glance knowledge of the space, complex CNC setups can have NP path routing problems to go from a model to the actual job. So I wouldn’t be surprised if the tools are underdeveloped. You’re only selling a couple of these machines to very sophisticated operators after all. There isn’t the scale/market to justify much polish.
- jdboyd 4y ago
  They might try, but it is hard to know which instructions will damage something. The machine might not not what the shape of the work piece inside of it is supposed to be, and if it doesn't know that, it might not know when one operation fails in a way that would now cause a later operation to incorrectly collide part of the machine with the work piece. On stupider machines that are only 10s of thousands of dollars/euros/etc, you also have to be certain that what the machine expects for tool geometry matches reality (meaning that the correct tool was in the correct tool location, that the tool is mounted in the holder at just the right length, that the tool itself hasn't deformed, etc. That said, I wouldn't bet against AI stuff potentially being good at generating tool paths in the future. Sometimes I think that existing CNC stuff might be too dumb. Where is the lathe equivalent of auto-probing a 3d printer bed or using machine vision to monitor the print? Where is the mill equivalent of visual examining each part like a pick and place machine does? Why can't I put a piece of metal in a vise and just tell the mill to square of the ends? It could be that what I'm picturing is only stuff that casual users would be interested in, and thus there isn't sufficient money to develop it.
  - di4na 4y ago
    Re auto probing: it exists but usually not at your level because you rarely need that precision for the work you do. On top of this, it gets far more expensive because the levelling mechanism end up having a precision cost too. Also let say that the use case are a bit different. a 3d printer is a far far far more controlled environment
    - Kirby64 4y ago
      The difference is simple, a 3d printer starts with nothing on the 'table' or platform and adds. It has 100% of the information of what is added, so in theory it's possible to know where any potential collisions are (this is not done in practice, and also doesn't account for adhesion print failures, etc, but it's possible). A CNC starts with an unknown block on the table, held by an unknown workholding fixture, made of an unknown material. There just is not enough information to not crash into something unless programmed around it. Or just run way too fast and destroy tools. In theory you could design sets of rules, but now you're having to add so much specificity to a design it's a big time waste. There's not really any meaningful entry level CNC machines, so if you can pay for the big machine... you kind of can pay for the expertise to not destroy the machine.
- auxym 4y ago
  Nope, not in my experience. They will happily ram themselves at full speed into your solid-block-of-steel workpiece if you tell them you (thereby probably causing tens of thousands of dollars in damage).
- at_a_remove 4y ago
  Terrifying amounts of no, not even a little.
- jacquesm 4y ago
  To some degree. But if you purposefully program in a toolstrike and ignore the warnings you'll get a toolstrike and depending on how beefy the tool/machine is the damage may well be considerable. Hold down clamps are a particularly good source of toolstrikes.

CoastalCoder 4y ago

I've never worked with a CNC. Wouldn't they typically have safeguards against machine-damaging instructions?

deleted 4y ago
[deleted]
jaipilot747 4y ago
Usually not. Especially not in machines where you manually set the bits and the machine has no idea of the bit and it's properties, nor of the piece you are machining.
Blackthorn 4y ago
What the machine knows: (1) Where the head is. (2) If you program it right, where the end of the tool is. (3) If you program it right, what the width of the cutting edge of the tool is. That's it. You could maybe prevent it from diving the tool into the table. But you won't prevent it from trying to take a 2" cut into D2 steel. Or going down into a pocket and crashing the tool holder into a section of the workpiece. Or going down into a pocket and rapid moving left, slamming the tool into the workpiece (which if you're lucky will just break the tool).
- mauvehaus 4y ago
  ... And depending on whether it uses steppers or servos, it may only know where the head is relative to where it was last told its origin was. ... And, if it's using steppers, it only knows that much if it hasn't slipped/missed/lost a step.
davemp 4y ago
From my at a glance knowledge of the space, complex CNC setups can have NP path routing problems to go from a model to the actual job. So I wouldn’t be surprised if the tools are underdeveloped. You’re only selling a couple of these machines to very sophisticated operators after all. There isn’t the scale/market to justify much polish.
jdboyd 4y ago
They might try, but it is hard to know which instructions will damage something. The machine might not not what the shape of the work piece inside of it is supposed to be, and if it doesn't know that, it might not know when one operation fails in a way that would now cause a later operation to incorrectly collide part of the machine with the work piece. On stupider machines that are only 10s of thousands of dollars/euros/etc, you also have to be certain that what the machine expects for tool geometry matches reality (meaning that the correct tool was in the correct tool location, that the tool is mounted in the holder at just the right length, that the tool itself hasn't deformed, etc. That said, I wouldn't bet against AI stuff potentially being good at generating tool paths in the future. Sometimes I think that existing CNC stuff might be too dumb. Where is the lathe equivalent of auto-probing a 3d printer bed or using machine vision to monitor the print? Where is the mill equivalent of visual examining each part like a pick and place machine does? Why can't I put a piece of metal in a vise and just tell the mill to square of the ends? It could be that what I'm picturing is only stuff that casual users would be interested in, and thus there isn't sufficient money to develop it.
- di4na 4y ago
  Re auto probing: it exists but usually not at your level because you rarely need that precision for the work you do. On top of this, it gets far more expensive because the levelling mechanism end up having a precision cost too. Also let say that the use case are a bit different. a 3d printer is a far far far more controlled environment
  - Kirby64 4y ago
    The difference is simple, a 3d printer starts with nothing on the 'table' or platform and adds. It has 100% of the information of what is added, so in theory it's possible to know where any potential collisions are (this is not done in practice, and also doesn't account for adhesion print failures, etc, but it's possible). A CNC starts with an unknown block on the table, held by an unknown workholding fixture, made of an unknown material. There just is not enough information to not crash into something unless programmed around it. Or just run way too fast and destroy tools. In theory you could design sets of rules, but now you're having to add so much specificity to a design it's a big time waste. There's not really any meaningful entry level CNC machines, so if you can pay for the big machine... you kind of can pay for the expertise to not destroy the machine.
auxym 4y ago
Nope, not in my experience. They will happily ram themselves at full speed into your solid-block-of-steel workpiece if you tell them you (thereby probably causing tens of thousands of dollars in damage).
at_a_remove 4y ago
Terrifying amounts of no, not even a little.
jacquesm 4y ago
To some degree. But if you purposefully program in a toolstrike and ignore the warnings you'll get a toolstrike and depending on how beefy the tool/machine is the damage may well be considerable. Hold down clamps are a particularly good source of toolstrikes.