Re: [CAD_CAM_EDM_DRO] um, is the dro acting wierd?

fignoggle wrote:

>i just noticed this the other day when drilling a series of holes in a
>plate.
>
>all measurements were spec'd, i just had to read off the dro to get my
>locations.
>
>after the second hole going onto the third, i noticed that what i was
>about to drill did NOT match up with the dro reading. it was off. so i
>stop and check my math, etc.. this happened all throughout the operation.
>
>same operation yesterday and noticed it again after zeroing x and y.
>knowing that something was wierd, i ran the axes to random points to check
>before i started drilling.
>
>and then the strangest thing. i saw the dro literally jump by .200" by
>itself. WTF? it happened all over the place and ONLY in the y axis. from
>1.000 to 0.800., etc..
>
>so, is this my scale? dro? cable?
>
>

Can't say for sure, but you have displays on the scales themselves, right?
Does the scale readout show the same error? If not, then the readout box is
definitely having trouble reading the info from the scales. Does this error
"stick", or does it flip back and forth between the right reading and
one that
is +/- .2" from the right value? Does the error accumulate over time?

Does it only happen when the spindle is running? At only one speed or
at all speeds?

There may be a way to ground the readout box to the machine frame
which may help.

Jon