Re: 3D Contouring - Loss of Accuracy - Follow-Up

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Peter <prenolds@s...> wrote:

> Hi Fred,
>
> I haven't backplotted the file because I'm posting files using G90 -

> absolute mode. But I'll send a file over just to be sure. Thx.
>

Boy do I wish we could view this thread all as a single conversation
instead of all spread out. ;-)

I got your file. It's about 20,000 lines of code. Can you process
the program at 5 decimals in stead of 4? Do you get the same error
at the end of the run?

My thought is that instead of a control system problem, it may be a
simple problem of truncating instead of rounding. Running an extra
decimal might improve the result. If I missed that you already tried
this, let me know & I will crawl back into my cave with the other
bears. Something else you might try, if the controller won't run
more than 4 decimals, scale the CNC file by 10 times and descale it
in the controller. If the post processor is truncating, but the
controller is not, you should see an improvement in accuracy with
this method.

This kind of problem along with the mechanical are the ones that we
never expect and it is very easy to start problem solving by looking
for an electronic or system software problem first and waste a lot of
time trying to solve the wrong problem. This is the voice of
experience, not the voice of criticism, having solved the wrong
problems many times myself.

Best regards and good luck,

Fred Smith - IMService

Names:26-27 April, 2003 Southgate, MI, USA CUthere