Quality Management 2017

4. Verification of the capability of the measurement system

M EASURE

Without being able to measure, impossible to quantify changes.

Part 1 :

+ Dispersion of the measurement system Consider the measurement as a process itself

Introduction to SPC

True dispersion of the process

Observed dispersion

=

Part 2 :

Essential concepts to start with SPC

• Capability of the measurement system (Cpc)  Repeatability and Reproducibility study (Gage R&R))

Reproducibility

Opérateur 1

Opérateur 2

N°

Cpc

Part 3 :

1ère mesure 2ème mesure

faisceau 1ère mesure 2ème mesure

system measure σ6 interval ion Specificat system measure  

R

R

X

X









1 -0,59% -0,39% -0,49% 0,20% -0,76% -0,44% -0,60% 0,32% 2 -0,21% -0,13% -0,17% 0,08% -0,44% -0,34% -0,39% 0,10% 3 -0,17% -0,19% -0,18% 0,02% -0,70% -0,47% -0,59% 0,23% 4 -1,19% -1,09% -1,14% 0,10% -1,19% -0,99% -1,09% 0,20% 5 -0,24% -0,40% -0,32% 0,16% -0,36% -0,59% -0,48% 0,22% 6 0,17% 0,20% 0,19% 0,03% -0,03% -0,26% -0,14% 0,23% 7 -0,67% -0,77% -0,72% 0,10% -0,85% -0,81% -0,83% 0,04% 8 -0,91% -0,66% -0,78% 0,24% -1,09% -1,07% -1,08% 0,02% 9 -1,35% -1,25% -1,30% 0,10% -1,39% -1,43% -1,41% 0,04% 10 -0,44% -0,24% -0,34% 0,21% -0,75% -0,71% -0,73% 0,04%

SPC in practice

2

2











system measure

repeatabil

ity

ility reproducib

Repeatability

-0,52% 0,12%

-0,73% 0,14%

R 2

X 2

X 1

R 1

Moyenne de et = -0,63% X 1 X 2

= Moyenne de et = 0,13% R 1 R 2

R

Part 4

Cpc = 3

Cpc = 1,5 Cpc = 2

Conclusion

Cpc = 4 Cpc = 100

Cpc = 1

Cpc  4  Observed dispersion  True Dispersion  Measure system statistically capable C ONCLUSION : measure system

Pp true

M. Pillet (2005)

03/10/17

Pp observed