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Worst use for a CMM?

OK hopefully this doesn't apply to everywhere but the engineers here seem to think that anything that needs measuring must automatically go on a CMM.... It has annoyed me since I started but most of the time I can see at least a little semblance of logic behind their thinking.


That is until now.......... We have a distance to measure (the height of an insert), now with a depth mic this could be checked within 30 seconds but let's be generous and include the time for me to go into my toolbox and get my mic, so we'll call it 2 minutes. Lovely quick turnaround everyone is happy....... Nope instead it MUST be measured on the CMM (which is running at max capacity and is looking like a 1.5-2 week lead time until I can squeeze it in).

Now I've argued every which way possible that it's a waste of time and the parts have been sitting on my shelf for a few days now and I have admitted defeat, but it got me wondering!

What is the worst thing you guys/girls have had to measure on a CMM?

If this gets no replies my faith in the world may be restored a little but if this goes the way I think it will at least I'll know I'm not the only one suffering and crying into my pillow at night.
Parents
  • Just to add a stupid request, once, a guy wanted to check the result of the cmm on a inner cone diameter, at a given depth (because the result wasn't what he was expecting... about -0.03 mm on a diameter larger than 300 mm !!!!!). With aroun 0.05 mm roundness...
    He asked me to check it with a caliper .....Slight smile
    Once again, I said "No" !!!!!

    Lessons about it :
    1- Teach peoples about uncertainties, algorithms, form defects, and explain what is a cmm result... After it, if they continue to ask stupid questions, you can't do anything for them...
    2- The cmm is not always the best tool to give a result, but it can give a little more information than 1d tools...But if a measuring tape is enough, use it ! (I never put a cinderblock on the granit !!!!!)
    3- If you understand what you measure, and can explain it, then you have the power of say "No" !!!!
Reply
  • Just to add a stupid request, once, a guy wanted to check the result of the cmm on a inner cone diameter, at a given depth (because the result wasn't what he was expecting... about -0.03 mm on a diameter larger than 300 mm !!!!!). With aroun 0.05 mm roundness...
    He asked me to check it with a caliper .....Slight smile
    Once again, I said "No" !!!!!

    Lessons about it :
    1- Teach peoples about uncertainties, algorithms, form defects, and explain what is a cmm result... After it, if they continue to ask stupid questions, you can't do anything for them...
    2- The cmm is not always the best tool to give a result, but it can give a little more information than 1d tools...But if a measuring tape is enough, use it ! (I never put a cinderblock on the granit !!!!!)
    3- If you understand what you measure, and can explain it, then you have the power of say "No" !!!!
Children