CNC isn't as predictable as you say. I have a Mazak mill with a control problem that after 3 tech's worked on it for almost 2 weeks they still couldn't figure out what was wrong and have referred the problem to the engineers in Japan. That was 3 months ago and they still don't have a answer. The controls today are very complex, couple that with multiple platform operating systems trying to talk to each other and it's almost impossible to predict what could go wrong. :confused2:
I never once said CNC was predictable, as a matter of fact I said just the opposite. What I said was programming is repeatable, if it did it once it would do it again at a regular interval. Basically if you read my comments in full you will see that, including the part about an E-stop. Unexpected is another way of saying unpredictable. I even said it could litterally be one of hundreds of things and listed a few examples.
You make my point for me, if it is a true control issue you are having with your machine, then it's probably not programming.
On another note I can sympathize with the mill problem. The company I work for has German, American, Italian, and Japanese routing and milling machines. All different operator controls, software, hardware and logic. Each has had issues that you can spend weeks on to find why something isn't working. Each OEM has different systems and styles of putting things together. Now you throw in programs and operators and it takes a few minutes just to see where the problem is. Again, not saying it's never programming, it'd just if it is I can make it do it again.
The scary part to me is, this is the way cars are being built today. All electric contols, not mechanical linkage or "hard" overrides.