How to simply calculate Measurement Uncertainty

  • Thread starter David Drue Stauffer
  • Start date
D

David Drue Stauffer

#1
I have the GUM Works Manual, I have excerpts from the Engineering Statistics Handbook, but I would like a step by step (simple)method for calculating and reporting the measurement uncertainty for M&TE calibration.
QS9000 says our calibration results should include this information, but provide no clear method of doing so. Does this stuff really have to be rocket science. I'm a big proponent of the kiss principle, "Keep it simple stupid".

------------------
Dave S.
 
Elsmar Forum Sponsor

Marc

Hunkered Down for the Duration
Staff member
Admin
#2
I have been reading about measurement uncertainty for some time. I have even set up a special sub-directory within the pdf_files directory. I know of no 'easy' answer. I suggest you read through some of the threads in that directory.

I did a forum search and found numerous 'hits' including http://Elsmar.com/ubb/Forum4/HTML/000072.html -- You might want to check out the thread.

That said, if ANYONE feels they can explain uncertainty easily and / or simply, I sure would like them to help us all out.
 
R

Ryan Wilde

#3
David,

There is no clear cut method of calculating measurement uncertainty. I highly suggest taking a course to become familiar with the concept. Once you understand the concept, and the statistics behind it, it actually becomes fairly easy. I say easy, as opposed to simple. After you take the classes, it is easiest to come up with a general list of contributing factors to calibration uncertainty, such as temperature growth of UUT and standard/M&TE, deformation, repeatability, master uncertainty, resolution error, etc.

I've been where you are, take the class. The books make great sense to me now, but before it was put into plain english, they were well above my head. To save yourself, and your company, some money I suggest you start with the simple one day "Intro" course. Quite often that is all that you will need.

Ryan
 
B

Benjamin

#4
Could someone please suggest source(s) for the training Mr. Wilde suggests?

Thank you.
 
T

TorqueGuy

#5
There is no easy way to calculate uncertainty as each type of measurement has it's own uncertainty contributors.

The easiest way I have found to calculate my uncertainty is to follow an example. You can find a very good example at *** DEAD LINK REMOVED *** click on the orange document.

You can also ask an expert. I called my local registration authority in Canada and talked with a metrologist for about an hour. He laid out what factors may contribute to uncertainty of my specific tests.

Now all I have to do is calculate it. That should be easy right? ;-/
 
B

BADKINS

#7
Originally posted by Benjamin:
Could someone please suggest source(s) for the training Mr. Wilde suggests?

Thank you.

Mitutoyo Technical Seminars may be a good source: One coming up May 17 in Charlotte, NC - "Estimating Measuring Uncertainty" - 1 day for $325/person. Touted as an entry level course covering ANSI/NCSL Z540-2, PUMA method based on ISO/TR14253-2. Check out thier web site: www.mitutoyo.com
 
L

lhiga

#9
Yes, I was like you, looking around for something NOT like the GUM document to figure uncertainty and I think I have found it. Get document ISO/TS 14253-2 This is the GUM PUMA method. This document will make you happy.
 
M

metrologyguy

#10
There is more to uncertainty calculations then comming up with numbers to pass an audit. We originally used a spread sheet from a consultant to just drop in our numbers and get some type of result. After months of preperation our A2LA assessment for calibration services started. Within the first few hours of a three day assessment, our assessor advised me that he will not accredit a lab that does not have someone on staff that can do detailed uncertainty budgets. I was shocked! After he explained his logic I understood and agreed. The process requires a person that truly understands all the variables, and in our case there are many. Thanks to his insistance to learning all of the details, we are a better lab. The person who recommended taking the Mitutoyo course is correct. I sent a Lab Technician to a course taught by Dr. Hendrick Neilson (Mitutoyo and A2LA instructor) and the technician's understanding is much better. Dr. Neilson also does private consulting, He can be contacted through A2LA.

------------------
 
Thread starter Similar threads Forum Replies Date
I Root Cause Analysis when someone simply stops performing a task? ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 16
Marc Cripple a Mac simply by duping them into visiting a malicious web site After Work and Weekend Discussion Topics 0
Manix Standard Operating Procedures (SOP's) - Are these simply Operator Work Instructions? Document Control Systems, Procedures, Forms and Templates 6
A AS9100 Quality Record - 4.2.4 simply states Records, not Quality Records Records and Data - Quality, Legal and Other Evidence 3
P Commercial excel templates that calculate overhead, hourly rates, fee proposal Excel .xls Spreadsheet Templates and Tools 0
M How to calculate benefits? Moving some developed non controlled software/automation systems Service Industry Specific Topics 2
qualprod Calculate number of people in processes, considering cycle time/takt time = quantity of people Lean in Manufacturing and Service Industries 9
S How to calculate the maximum allowable hysteresis of a pressure gauge General Measurement Device and Calibration Topics 1
S How to Calculate the producer Risk AQL - Acceptable Quality Level 25
qualprod Methods to Calculate Available Production Rate ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 0
K Why calculate LCL in P-chart? Statistical Analysis Tools, Techniques and SPC 4
B How to calculate CPK with n = 1 Manufacturing and Related Processes 2
A Add-On software for VMC to calculate setting time, Idle Time, OEE etc.. Manufacturing and Related Processes 2
L How to calculate the Probability of Deficiency of the AQL of an Inspection AQL - Acceptable Quality Level 16
V How to Calculate Unbiasing Constant C4 Statistical Analysis Tools, Techniques and SPC 1
J How to Calculate OEE Indicator for a Workshop (15 Machines) Lean in Manufacturing and Service Industries 6
R How to calculate UCL (Upper COntrol Limit) and LCL (Lower Control Limit) Statistical Analysis Tools, Techniques and SPC 5
T I want to calculate reliability at 750 hours Reliability Analysis - Predictions, Testing and Standards 8
R How To Calculate & Print CDF and Lower Bound CDF value for some t(time) with Minitab? Using Minitab Software 1
N How to calculate the Premium Freight charges Service Industry Specific Topics 4
A How to calculate Mean and standard deviation without sample size in Minitab Using Minitab Software 5
R When do I need to calculate Process OEE? Manufacturing and Related Processes 12
kedarg6500 How to calculate Thread Pitch Diameter for non standard TPI like 5/8" 17.75 NF3 Manufacturing and Related Processes 3
C Definition and Way to Calculate some Metrics Lean in Manufacturing and Service Industries 6
M How calculate P value for Linearity and Bias using Excel Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 8
N Formula that will calculate the NoGo Major Diameter of an M20 x 1.5 6H Thread gage Inspection, Prints (Drawings), Testing, Sampling and Related Topics 3
M How to calculate Cg and Cgk for a 2-Dimensional Area Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
T Calculation Question - Calculate the runner weight for a part Manufacturing and Related Processes 2
M Spreadsheet on How to Calculate SMT Capacity wanted Manufacturing and Related Processes 2
F How to Calculate the unbiased Standard Deviation in Excel using Minitab Formula Capability, Accuracy and Stability - Processes, Machines, etc. 6
S Spreadsheet that will Calculate Audit Duration times based on IAF MD5 and MD11 Excel .xls Spreadsheet Templates and Tools 7
M Calculate PPMs by going back to Date of Production or Date Noticed Quality Tools, Improvement and Analysis 7
M How to calculate MTTF (Mean Time to Failure) Reliability Analysis - Predictions, Testing and Standards 1
H How to calculate the Lot Reject Rate Inspection, Prints (Drawings), Testing, Sampling and Related Topics 4
L How calculate the number of samples Statistical Analysis Tools, Techniques and SPC 2
A Simple 125 piece part Capabilty Excel .xls sheet to calculate Cpk Capability, Accuracy and Stability - Processes, Machines, etc. 3
R How to calculate MMC when is placed after datum Inspection, Prints (Drawings), Testing, Sampling and Related Topics 4
S Which one is better to calculate, Cpk or Ppk? Statistical Analysis Tools, Techniques and SPC 11
C How to calculate P value on Probability Plot Statistical Analysis Tools, Techniques and SPC 1
S Supplier Disruption Score and how to calculate it Quality Tools, Improvement and Analysis 4
D IAQG OASIS - New tool to calculate Audit Time AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 1
M How to calculate dimensions of trapezoid ? Quality Tools, Improvement and Analysis 3
J How to calculate Surveillance Audit Days in Corporate Audit Scheme IATF 16949 - Automotive Quality Systems Standard 4
S How to calculate Supplier PPM at Receiving Inspection Document Control Systems, Procedures, Forms and Templates 2
K How to Calculate Sample Size at 95% Confidence Interval on Surface Roughness Inspection, Prints (Drawings), Testing, Sampling and Related Topics 1
R How to calculate the value add time? Lean in Manufacturing and Service Industries 2
G Should I calculate both Cp and Cpk for a Unilateral Tolerance? Statistical Analysis Tools, Techniques and SPC 8
H Continuous Monitoring Instrument Data Validation and how to calculate Outliers Quality Tools, Improvement and Analysis 1
R How to calculate the Air Flow Rate in clause 201.12.4.4.105 of IEC 60601-2-16:2012 IEC 60601 - Medical Electrical Equipment Safety Standards Series 1
A How to calculate Cpk & Ppk if the tolerance changes during the period? Capability, Accuracy and Stability - Processes, Machines, etc. 5

Similar threads

Top Bottom