Measurement Uncertainty

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Viewing 7 posts - 1 through 7 (of 7 total)
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• #53514

Patel
Participant

Hello guy,

I was wondering if anybody has performed any experiment to find the uncertainty of the measurements taken by an equipment. I am trying to create a table for the optical microscope that we use in our laboratory that would enable us to tell our customer something along the lines like, ‘the length of this object is X micrometer’ with a plus/minus Y micrometer where the real value might lie in’. Any suggestions/ help will be appreciated.

Thanks

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#191141

Rasheed
Participant

hi…Jimmy.

there are two thing. 1) precision of your equipment, this can be tell be the manufacturer and hopefully this will resolve your problem. and 2) if uncertainty is due to an operator of equipment then it cannot be calculated either way, as this point will vary operator to operator.

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#191182

Breytenbach
Participant

Hi Jimmy, I’m fairly new to iSixSigma and saw your “old” but never outdated request. I developed a spreadsheet, based on QS 9000, (99% confidence, TYPE 1: PRODUCT SPEC EXISTS) guidelines for MSA that may help you. You enter the data and it will analyse and check, against QS 9000 requirements, whether the Resolution, Bias (or Accuracy as some call it), Repeatability and Reproducibility (R&R) are adequate. It also takes the R&R results and calculate a measurement uncertainty. It also plots the MU as an normal curve around the spec values.
I developed it for my own use at companies where we implemented SPC systems. It is thus not so user friendly as it could be. As long as you stick to what you see in the spreadsheet, it is OK, that is:
– testing Bias with max number of 25 reading
– Determining Repeatability (no Reproducibility) with 1 operator, max 32 parts with max 4 readings per part.
or – determining R&R with max 3 Operators, max 10 parts and max 4 readings per part.
For MU, calculates and plots (normal curve around spec values) the Lower and Upper Discrimination Values.
I need to guide you through this, as it not only calculates actual values for all above (which I call Performance), but also the potential best as reflected by the samples (which I call Capability).
Find attched a picture titled MSA Example that you can zoom into to give you an idea of the outputs. Give me a buzz at [email protected] if you think it might help you.
Quality greetings
Wynand

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#191183

Breytenbach
Participant

Sorry Jimmy, after several attemps, I couldn’t succeed in adding the image. Maybe it is too large. E-mail me and I will forward.
Wynand

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#191339

Fúquene Moreno
Participant

Hi, How’s going?

My name is Philip, I’m from Colombia and live in Bogota, I’m Industrial Engineer and work as Process Engineering. Now I want to now, what looking for the Professionals when trained in Six Sigma (paid well, stability, etc), and if they feel that company promotes programs to retain them.

I have a small survey, could you help me, let me know what do you think about it?

Regards!!!

Felipe Fùquene Moreno
Industrial Engineer
Colombia :laugh:

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#191344

Rasheed
Participant

HI Feilipe….
Industrial Engg. is the base of Six Sigma concepts and the question you have for growth and retaining the professionals depend and varies on company to company.

how ever, when you analyse the result of your survey and come to some conclusion then please send me on below address.

thanks
Mamoon ur Rasheed
Industrial Engineer.

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#191346

James Lauer
Participant

Jimmy,
Good question. Measurement System Analysis is the experimental technique to understadn your measurement tool, including estimate of variability. Your question sounds like it is asking more than one thing. But MSA has various techniques to understand calibration as well as usage. Good luck.

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