Calibration 101 refresher training for all levels

CALIBRATION TRAINING

1. HELLO! I am YK Tang | HRDC Trainer | Quality & Process Improvement Specialist | Supply Chain Black Belt | Pro Photographer | Coffee addict | Car enthusiast 1

2. Measurement Our daily life is based on measurement Measurement is the first step that leads to control and eventually to improvement - if you cant measure something, you cant understand it. If you cant understand it, you cant control it, and if you cant control it, you cant improve it.

3. Measurements are made to support decisions or establish facts. If measurement data are not used in a decision, the measurement is unnecessary So, how much can we trust our data / measurement?

4. Think What if pasar malam hawker’s scales not accurate? What if police speed trap radar gun is not accurate?

5. Measurement error – what can lead to ? Measurement error is considered to be the difference between a value measured and the true value. Error in Measurement will results in alpha and beta risks for both the producing organization and its customers Type 1 error = producer risk = false alarm Type 2 error = consumer’s risk = miss rate False alarm rate + miss rate = Error rate Good NG Reject Accept OK OK

6. What is Calibration? definition Process of comparing of a measuring equipment with a reference standard to detect and quantify measurement errors and to report or eliminate these errors Measurement of Accuracy · Establishment the relation of an instrument ’ s accuracy to the international standard

7. Calibration Traceability

8. Calibration vs verification

9. Calibration needs in ISO9001:2015 Element XXX ?? refers to monitoring and measuring resources What are monitoring and measuring resources?

10. ISO9001:2015 The organization shall determine and provide the resources needed to ensure valid and reliable results when monitoring or measuring is used to verify the conformity of products and services to requirements The organization shall ensure that the resources provided: A) are suitable for the specific type of monitoring and measurement activities being undertaken; B) are maintained to ensure their continuing fitness for their purpose The organization shall retain appropriate documented info as evidence of fitness for purpose of the monitoring and measurement process

11. ISO9001:2015: Measurement Traceability When measurement traceability is a requirement, or is considered by the organization to be an essential part of providing confidence in the validity of measurement results, measuring equipment shall be: A) calibrated or verified, or both, at specified intervals, or prior to use, against measurement standards traceable to international or national measurement standards; when no such standards exist, the basis used for calibration or verification shall be retained as documented information B) Identified in order to determine their status C) safeguarded from adjustments, damage, or deterioration that would invalidate the calibration status and subsequent measurement results The organization shall determine if the validity of previous measurement results has been adversely affected when measuring equipment is found to be unfit for its intended purpose, and shall take appropriate action as necessary

12. Understand some calibration terminology

13. There is no such thing as perfect measurement All measurements have errors and uncertainties, no matter how hard we might try to minimize them

14. What is an error? Measured Value – True Value Example, assume a stick rod of true value of 25mm, and a measured value of 24mm, therefore the error is 1mm Reference Value Accuracy (Bias/error) Distribution of repeated measures on a single specimen or part Precision - Repeatability - Reproducibility

15. Example calculation Actual value, true value = 0.20 0.21 0.25 0.23 0.22 0.21 0.20 0.20 0.20 0.21 0.23 0.19 0.24 0.20 0.18 0.23 0.21 0.20 0.22 What is the measurement error? Average = 0.213 Measurement error = 0.213 – 0.20 = 0.013

16. Understand Measurement Error / correction The results of calibration is sometimes expressed as a ‘correction’ or ‘measurement error’ on calibration certificate / report Example Correction is the value added algebraically to the uncorrected result of a measurement to compensate for systematic error Thus, correction for the above; Correction = -0.002 mm Nominal / true value of measurement 1.000 mm Measured value 1.002 mm Measurement error +0.002 mm

17. Do we need to apply the correction factor into all our measurements ? NO !! Only for readings where correction is higher than the permitted customer specifications / tolerances Some companies will use the Permissible Error, or Max Permissible Error (MPE) to gage. Minimum permissible error use is 1/3 of the spec tolerance. i.e. if the drawing stated 10cm +/- 0.01 cm, the MPE = +/- 0.003cm

18. What are the alternative ways to apply correction for errors as per the calibration cert? Direct application using the correction value Using the nearest reported correction value in the cert Averaging between 2 correction factors Using linear interpolation to determine any value between 2 points

19. Example Direct application Let say you want to find the correction factor for 20. Correction = 20.000 – 19.955 = 0.045

20. Example 2) Using nearest reported value If we want to look for value 38, the nearest value is 40, therefore we will use the 40 correction factor which is 0.089

21. Example 3) Averaging between 2 correlation factors If we need correction for value 25, so the value is between 20 and 30 CF = (0.045+0.063)/2 = 0.054

22. Example 4) Using Linear Interpolation Use the formula of y=mx +c Imagine if we want to look for CF for 37…..please work on the calculation.. CF should be 0.0812

23. What is uncertainties (measurement uncertainties) When engineers make a measurement or calculate some quantity from their data, they generally assume that some exact or  "true value"  exists based on how they define what is being measured (or calculated). Engineers reporting their results usually specify a range of values that they expect this "true value" to fall within. The most common way to show the range of values is: Example if a measured value is 5.07mm, with a measurement uncertainties of +/- 0.02, the actual value can be lies between 5.05 to 5.09 True measurement = observed measurement (result) ± U, U = term for expanded uncertainty of the measurand and measurement result.

24. Confidence Level The confidence level tells you how sure you can be The 95% confidence level means you can be 95% certain Normal confidence level will be set at 95% 34.1% 13.6% 2.15% 34.1% 13.6% 2.15% 68.2% 95.4% 99.7% +2s +3s +1s -2s -1s -3s 2 sigma K=2  confidence level of 95%

25. Types of uncertainties Uncertainties can arise from Measuring device Procedure of how you measure Observed quantity itself Systematic uncertainties Systematic uncertainties or systematic errors always bias results in one specific direction, which can be inherent from the equipment. Random uncertainties Can be from a lot of factors, such as humans, method of use, environment, etc

26. Understand calibration certificate What do you do when you receive the calibration certificate? What are the key information in the certificate concern you? Just file it? Or show auditors that you have a cert? Looking at the due dates only ?

27. What should a calibration certificate include? Calibration certificate number Details of the laboratory tasked with calibration – SAMM logo, etc Customer info The equipment name and details (serial numbers) Evidence that the measurements are traceable Calibration results / correction factors, etc Calibration methods Calibration date Re-calibration due date Details on lab conditions where the calibration took place Name and signature of person performing the calibration Measurement uncertainty results Reference used

28. What to look for? Correction Factor Uncertainty

29. As Found / As Left As-Found: Indicates if the module is within specifications on arrival and before performing the adjustment process. As-Left: Indicates if the device is within specifications after the adjustment and also if it is likely to stay within specifications for another calibration interval. Check if value is within Upper and Lower Limit

30. Determine if your instrument is fit to be used or not based on calibration cert Determine your process tolerance Check the specifications of the instrument in the user manual Use the uncertainty results

31. Estimated based on Process Tolerance Example, if the error displayed in the calibration certification during the calibration on the 20mm range is +0.06mm User has a process tolerance base don their process which is +/- 0.04mm, then this means that it is already out of tolerance Unless, you can use it as it is, and inform operators of the correction factors

32. Check the specifications of the caliper in the user manual, look for accuracy specification / instrument tolerance Based on this, you can use the TUR method…

33. TUR – Test Uncertainty Ratio The  Test Uncertainty Ratio (TUR)  is a measure used in calibration to determine the quality of a measurement system. TUR is defined as the ratio of the accuracy (or precision) of a measuring instrument to the uncertainty of the calibration process. It provides a way to compare the potential measurement error of a calibrated instrument to the accuracy of the calibration standard used. The comparison between the accuracy of the UUT and the estimated calibration uncertainty is                  known as a Test Uncertainty Ratio (TUR)

34. TUR TUR = TOLERANCE LIMIT EXPANDED UNCERTAINTY Typically, a TUR of at least 4:1 is considered acceptable in many industries, meaning the calibration uncertainty should be four times smaller than the tolerance of the UUT. A TUR below 4:1 may require additional considerations or adjustments to ensure measurement accuracy. Example: Instrument tolerance = +/- 0.1, expanded uncertainty = +/- 0.02 TUR = 0.1 / 0.02 = 5 The TUR in this example is 5:1. This means that the calibration uncertainty is five times smaller than the instrument's tolerance, which is generally considered a good TUR, ensuring that the measurement system is accurate.

35. The myth about calibration The presence of the calibration cert means that the measuring instrument is reliable and can provide accurate and reliable results After calibration, an instrument can be used with confidence for the time specified by the calibration period What do you think ?

36. Understand MSA Precision The degree of agreement (or variability) between individual measurements or test results from measuring the same specimen(s) Accuracy The difference between the average of the measurement error distribution and the reference value of the specimen measured

37. Accuracy… Error / Bias Linearity Stability Repeatability Reproducibility Precision..

38. What is ISO17025 ISO/IEC 17025 is the standard for general requirements for The Competence of Calibration and Testing Laboratories Many countries have adopted ISO?IEC 17025 as the basis for establishing quality systems and recognizing the competency of calibration laboratories by 3 rd party accreditation In Malaysia, the government has established National Laboratory Accreditation Scheme on 15/8/90 which known as SAMM (Skim Akreditasi Makmal Malaysia)

39. Accreditation illustration Ministry of science, technology and environment Department of Standard Malaysia (DSM) Accreditation division National Metrology Center (NMC) Calibration and testing lab Company lab / user equipment To accredit To certify To accredit

40. Basic of requirements for calibration Reference / calibration standards and other instruments and equipment Controlled environment conditions Competence of calibration lab personnel Traceability of reference / calibration standards Documentation Safeguard calibration integrity

41. Calibration status indicator To enable the user to know the equipment calibration status easily Types of calibration status indicator to be considered as follow: Self-adhesive sticker Tie-on label (for oily environment) Permanent market through engraving What sort of information should appear on the status indicator?

42. Safeguard Calibration integrity Access to adjustable devices on measuring equipment whose setting affects validity of measurement results shall be sealed or safeguarded to prevent tuning by unauthorised personnel Common method: integrity seals, password for test software, locked with key, etc (anything else?)

43. Before calibration… Check for any signs of outward damage, Chipped measuring faces Bent anvil (micrometer) Loose or missing parts Dirt or damaged track or gear All parts must be kept clean during calibration Wipe equipment clean with cloth and apply a drop of fine oil to spindle (micrometer)

44. Documentation In any quality system, documentation has very important role and therefore proper care shall be taken for documenting Calibration procedure Calibration results Calibration report Calibration certificate

45. Let’s connect !