356 / 879
Related to the specifications
Related to the target
Pp
Ppk
Ppm
6
interval
ion
Specificat
Pp
Dispersion
D1
D2
Pp = Ppk = 1
Ppk = 2
2
2
2
)
(91
6
Ppk
Pp
Pp
Ppm
target
X
Interval
ion
Specificat
Ppm
✓
Calculate the three indicators to be able to identify
the reason why data are outside the specifications.
Target
Dispersion
USL
LSL
Specification interval
Dispersion
Target
Loss Fonction
L = K(X-Target)²
X
Dispersion
Dispersion + position
USL
LSL
USL
LSL.
8. Calculation of the performance indicators
Ppm < 1
Part 1
:
Introduction to
SPC
Part 2
:
Essential
concepts to
start with SPC
Part 4
Conclusion
Part 3
:
SPC in
practice
A
NALYZE
0.27% out of spec.
✓
Aim: to get indicators as high as possible.
21
Ex.:
Ex.:
Ex.:
3
)
();
(
2
1
LSL
X X
USL Min
D
D
Ppk
03/10/17
USL
LSL
Ppk=1.00
Ppk=1.33 Ppk=1.67 Ppk=2.0
Ppk
Proportion of data out of spec.