Total Resolution of an Measurement Instrument


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If the ndc is 1 this means that we do not have an adequate measuring system. I have to inform you that % Study Var is 98 % and i see one action to be made to improve ndc is to change the resolution of the instrument. The tolerance range is 0.020 mm and the process variation is approx. 0.0085 mm.

The resolution of an instrument should be better than 5% of the tolerance as well as of the expected process variation which means the resolution should be at least 0.05x0.0085=0.000425 mm

When we did the MSA the measuring system could only detect 0.001 mm. Should we change to better resolution from 0.001 to 0.0005 and can this help the result of ndc & % Study Var to be better?


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Is the major source of variation from Repeatability or Reproducibility?

If resolution is an issue, it will primarily affect Repeatability. If Repeatability is the major source, look at your Range chart. Does the resolution of your gage provide at least 5 distinct levels within the UCL of the Range chart, and are less than 25% of the ranges = 0? If you meet these criteria, a new gage may not help. If you violate these criteria the new gage should help.
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