Re: [CAD_CAM_EDM_DRO] Just How Accurate Is CNC?

Hi Chuck,

I am afraid you have got your units slightly mixed up. At 20MHz the pic
is executing each instruction in 50ns. We need a resolution of 0.000150 ns.

Light is just too damn fast :-)

Les


Chuck Rice wrote:

>
> So 150 fs = 0.000150 ns
>
> A crystal 20 MHz PIC can run at 5,000,000 instructions per second.
> Doesn't that give a headway of 75 instructions per required resolution?
> Perhaps my math is off, but if not, with a PIC chip, you can do a
> lot in 75 instructions. If you wanted to drop it a notch tighter,
> 15 fs would give you 7.5 instructions per second. That might be
> pushing it.
>
> I doubt that I have enough knowledge to do it, but I think that
> someone will be doing it soon. Too many of the pieces are becoming
> available at low price points.
>
> Seems, even if you wanted to laser engrave a scale on the bottom of a
> table, you could read it much the way we read a micrometer. You
> could have a set of LEDs that read the course scale and another set
> matched the fine scale. The two readings together would give you
> a pretty fine resolution.
>