Re: [CAD_CAM_EDM_DRO] Coordinate Measuring Machine

Most people operating CMMs aren't taking point clouds or doing any sort of
scanning. They're taking a few (typically 3-9) points on each feature for
the purpose of inspection or occasionally reverse engineering. Most often
the plane or direction of contact is quite predictable.

On Sun, Dec 4, 2011 at 04:39, Steve Blackmore <steve@...> wrote:

> **
>
>
> On Sun, 04 Dec 2011 07:31:36 +0100, you wrote:
>
> >Almost all probe designs I have seen are not, in my mind, adquate.
> >Basically, because their premise is that creating a "touch" is
> >sufficient without any regard to the plane, direction, etc of the contact.
> >Thus they make a point cloud in a fairly repeatable, but by no means
> >accurate manner.
>
> ALL the CMM machines I've seen use Renishaw type probes. So in everybody
> else's mind they are perfectly adequate.
>
> The probe is touched off and calibrated against a home device (often a
> sphere of known dimensions) and then the measurements take place.
> Repeatability is excellent.
>
> That type of probe design is easy to make, the patent has expired and
> was never enforceable anyway, as the idea was prior use.
>
> Steve Blackmore
> --
>
>
>


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