KERN YKT-01 Bedienungsanleitung Seite 75

Machine Potential
OGW–UGW
Cm =
σ
6
n-1
Machine Capability Index
Cmk = Minimum_of_
Process Potential
−
OGW UGW
=
Cp
σ ˆ
6
Process Capability
Cpk = Minimum_of_
Estimated value for the standard deviation
R
σ= m
, whereby "d2" is representing a constant dependent on the sample size (table)
d2
Mean value for the standard deviation
R +R +...+R
1 2 n
, whereby "m" represents the number of samples
Rm =
m
Range of individual sample
R = x – x , whereby x
n n min n min
Table of Formula Constants
2
Stpgröße
d2 1.28
8
Stpgröße
d2 2.847 2.970 3.078 3.173 3.258 3.336
14
Stpgröße
d2 3.407 3.472 3.532 3.588 3.640 3.689
20
Stpgröße
d2 3.735 3.778 3.819 3.858 3.895 3.931
OGW–Xm Xm–UGW
_resp._
3 σ
n-1
OGW–Xm Xm–UGW
_resp._
3σ
= max. value resp. x
n max
3 4
1.693 2.059 2.326 2.534 2.704
9 10
15 16
21 22
3 σ
n-1
3σ
= min. value of the sample
n min
5 6 7
11 12 13
17 18 19
23 24 25
75