1. Repeatability & Reproducibility
הישנות ו הדירות
Repeatability and Reproducibility (R & R) Studies
Evaluate the precision of a measurement system.
It is important that the gauge be properly calibrated
Before starting the Gauge R & R Study.

2. Precision and Accuracy

3. Within Inspector Error between Inspector Error
Precision
Is the closeness of agreement between randomly selected
individual measurement or test results.
Precision
Repeatability Problem:
The same person (or station)
can’t get the same result twice on the same subject
Reproducibility Problem:
Different people (or stations)
can’t agree on the result obtained on the same subject
Within Inspector Error
between Inspector Error

4. Gauge Repeatability & Reproducibility
Gage R&R is a study to measure the measurement error in measurement systems.
The 10% rule tells us that
if the percent of tolerance consumed by the R&R does not exceed 10%, the measurement system is excellent.
R&R = 15% means that 15% of the variation in
product measurements is due to the measurement
System.

5. Total observed variance
Each independent component of the model is variable:
Product quality characteristic -
Gauge, measurement error -
Total observed variance in product quality characteristic measurements:

6. Gauge variance
If more than one operator used in study then measurement (gauge) error has two components of variance:
Repeatability:
- Variance due to measuring instrument
Reproducibility:
- Variance due to different operators

7. Experiments to estimate the components
&
are called:
gauge repeatability and reproducibility studies
(gauge R&R studies).

8. Repeatability & Reproducibility Report
n - number of parts r – number of operators
For example :
2 operators, r= j=1…r
10 items , n= i=1…n

9. Repeatability = Equipment Variation
Average and Range method
Repeatability = Equipment Variation
Standard deviation for Repeatability
Where d2 is a factor that depends on the number of trials (sample size): n 2 3 4 5 6 7 8 9 10 d2
1.128
1.693
2.059
2.326
2.534
2.704
2.847
2.970
3.078
Trials 2 3 4 K1
4.56
3.05
2.50
זהו החלק של השונות, בטווח הסיבולת, הנגרמת ע"י הציוד!

10. Average and Range method
Reproducibility = Appraiser Variation
Standard deviation for Reproducibility
Operators 2 3 4 K2
3.65
2.70
2.30
זהו החלק של השונות , בטווח הסיבולת, הנגרמת ע"י המפעילים!

11. Combined Gage Variation
זהו החלק של השונות , בטווח הסיבולת, הנגרמת ע"י מערכת המדידה!