Re: Probing

["Pete Cook" <kf2qd-at-terraworld.net>]

----- Original Message -----
From: "Dean L. Hedin" <dhedin-at-vsi.net>

A more approopriate and universal probe might be a ball end (spherical)
probe and a ball end mill to reproduce the surface - you just might have to
use a very small ball. And you still have to know something about the part
being probed to get useful results - remeber the story about the 5 blind men
and the elephant?

> FYI, Probing will always be imperfect. Consider the following little
thought
> experiment:
>
> We are on a 3-axis machine and I take a small cylinder and I cut it
> longitudelly in half and lay it on the table flat side down. I probe this
3d
> surface with a probe shaped like a normal cylidrical router bit.  I then
> create some g-code from this point cloud.
>
> I then machine a block of material using this g-code with a bit that
matched
> the probe.  I end up with little ridges along the raising & falling arcs
of
> the surface but no ridges along the top.  If I take very small cuts I can
> minimize these ridges but I can't get rid of them.
>