Re: [CAD_CAM_EDM_DRO] Re: Coordinate Measuring Machine

On Sun, 04 Dec 2011 19:04:05 -0000, you wrote:

>--- In CAD_CAM_EDM_DRO@yahoogroups.com, Michael Fagan <woodworker88@...> wrote:
>>
>> 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.
>
>Correct. A CMM machine is normally not used as a scanner. Instead it is used to verify (inspection) or determine relative location of (reverse engineering) circles, planes, edges, lines, etc. So as you say it is only a few points per item. 3 points and you have defined a plane. Maybe one or two more to average out the surface a little. about 4 - 5 points on a hole and you have the hole location and diameter. All 2D geometry that you probe and the software relates them together in 3D.
>
>There is a newer "scanning" style of probing that is growing. Primarily for parts that are 3D machined and not prismatic. In this the CMM moved along a path and the probe head sweeps the probe back and forth and reads as it goes. Very high end and not needed for most use. Just the special probe heads are in the $15K range.

Hi Tim, there are several distinct applications for CMM machines, there
is the basic automatically measure known points and tell me those
positions to the reverse engineer an unknown part. The behaviour differs
enormously but all these answers are way off what was asked....

The original question was

"Im making a CMM trainer as my final year engineering project... i m
facing problems.. reinshaw probes are very expensive and not
economically feasible for a trainer.. any idea?"

Make one is my answer....

Steve Blackmore
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