Brad Gover
Involved In Discussions
Hi All, I have a problem in calculating the thickness of a coating material inside a tube. The tubes inside diameter is measured before and after coating. The coating thickness is calculated by substracting the diameters and dividing by two to get the thickness of the coated material. The before coat diameter is 0.3949". The after coat diameter is 0.3893". The Total Gage R&R standard deviation is 0.000127". I need to calculate the coating thickness value and its associated error.
I am thinking the thickness without error = (0.3949 - 0.3893)/2 = 0.0028"
The associated error from the resulting calculation would be
± Error = [5.15 * (0.000127”2 + 0.000127” 2).5]/2 = ± 0.000462”
I would record the thickness as 0.0028 ± 0.000462”?
I saw some examples where they standard deviation was used in place of the 5.15 multiplier value i.e., 0.0028 ± 0.00018. I would think this would only capture some 66% of the uncertainty.
P.S. I used Big 3 MSA value of 5.15 instead of 6
Thanks, Brad:truce:
I am thinking the thickness without error = (0.3949 - 0.3893)/2 = 0.0028"
The associated error from the resulting calculation would be
± Error = [5.15 * (0.000127”2 + 0.000127” 2).5]/2 = ± 0.000462”
I would record the thickness as 0.0028 ± 0.000462”?
I saw some examples where they standard deviation was used in place of the 5.15 multiplier value i.e., 0.0028 ± 0.00018. I would think this would only capture some 66% of the uncertainty.
P.S. I used Big 3 MSA value of 5.15 instead of 6
Thanks, Brad:truce: