CMM's

[MIRCS]

Who uses em?

What do you use em for?

How do you like em?

[ck454ss]

A lot of manufacturing companies use them. (Automotive/Aerospace etc.)

They are used mostly for 3d measurements of parts.  With the proper programing its a "set part up let cmm take measurements"

They are good for 3d measurements but people do get fooled on the "true" accuracy of cmms.  Its all about volumetrics. XYZ Linears may be accurate to 0.0001" but volumetrics may be good to only 0.0004".

[RedBones]

We've got two here in our precision inspection department, a 4'x6' and a 4' x 12', both Brown & Sharpes with laser comp cals.  (We make rocket parts in house.)  I've tried using them for a few oversized tools, like checking parallelism on 48" calipers, but for the most part they are just not accurate enough to cal with.  We're talking +/- .0002" volumettric accuracy.  The repeatability is something like 2 microns, but that just ain't enough to overcome. 

Still love analog gage blocks that don't require an hour of set up programming and fixturing.

If you can justify it, I say go for it.  At the minimum they're neat to play with....

[USMCPMEL]

I can not find a manual for the one at my company but the dude who does the calibration told me it is accurate enough to calibrate gage blocks of course it cost over $100K so it all depends on what you want to spend.

[MIRCS]

We actually have six of them.

Three of them are Brown and Sharpe Globals, one an old DEA, a Zeiss that is accurate enough to calibrate gage blocks and a Leitz the size of a Dump truck that just about as accurate as the Zeiss.

You can't beat them for calibrating fixtures as in Bore sites and other types. Especially when doing true positions for parts of the fixtures.

We also have a couple leica laser trackers that are changing the way things are aligned and put together.

[MIRCS]

Any other thoughts from folks about CMM's?

since I strated this thread I've become more familiar and comfortable using the CMM to perform calibrations.  We use our Zeiss to calibrate all the ring gages