Re: [CAD_CAM_EDM_DRO] Machine security and safety

ccs@... wrote:

> In reality, any machine tool connected to any computer that is connected
> to a network should be considered insecure.

I suspect it could be hard to break into my CNC machine, with its 10.10.1.x
address, but someone could telnet to it through the node that does have
a real outside IP address.

> And any cnc machine (at least one that is out of e-stop) should be
> assumed to be able to start moving at any time and crush any body
> parts in its path, due to security breaches, bugs, glitches, encoder
> failure, or simply bad luck.

I have had only one incident with my system. I had partially removed a
boring head from the spindle, but needed a little more clearance to get
it out. So, while holding the boring head in my hand, I reached over and
hit the jog button to raise the spindle. The spindle and boring head
came down on several fingers, squashing them quite painfully. I sat
there for about one second, analyzing what had just happened, and
trying to decide whether I pushed the wrong button, or the CNC control
had malfunctioned. If it malfunctioned again, it would break my fingers
for sure. I had to decide whether to estop and wind the spindle up
manually, or just carefully press the correct button. What to do?!?!?
Well, I finally decided operator error was 10X more likely that machine
error, so I carefully pressed the right button, and the spindle went up!
Whew! My fingers were sore for a week.

I have also broken a 3/8" end mill clean off in the spindle (while not
turning), plowed a drill bit 1" through a block of aluminum at 45 IPM
when I forgot to set the Z-reference point, and such stuff. I also found
out how amazingly fast a 1/8" solid carbide end mill can cut through
1/8" aluminum sheet without breaking when I accidently set the
Z height wrong on another program. It was plowing through the
material at 45 IPM, thinking it was supposed to be rapid feeding above
the part!

So, operator error dominates in my shop, at least. I'm getting better,
but you have to work very carefully and deliberately to not have these
sorts of accidents.

Jon