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
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