Process Capability: CP
IT
CP
=
------
6σ
where:
•
IT = tolerance interval = Max. Tol. - min.Tol.
σ = Standard deviation
•
Coefficient of position and dispersion: CPK
–
Tolmax X
〈
CPK
=
min
---------------------------- -
3σ
3 - NF STANDARD E 60-181
s
= estimator of the intrinsic standard deviation for each mode number, where
ie
n
2
∑
(
)
x
–
x
je
e
j
=
1
s
=
----------------------------------
;
x
ie
n 1
–
k
1
2
∑
Di
S
=
-- -
s
;
i
ie
k
e
=
1
IT
CAM
=
----- -
Di
n
2
∑
(
)
x
–
x
j
j
=
1
s
=
----------------------------- -
where
p
N 1
–
x L
L
–
x
–
s
Cpk
=
Min
[
------------- -
,
------------- -
3s
3s
p
IT
Cap
=
------- -
6s
p
4 - NORMAL DISTRIBUTION TEST: POPULATION UNDER 50 MEASUREMENTS (SHAPIRO-WILK
TEST)
2
1) Calculation of
:
S
N
2
2
∑
(
)
S
=
X
–
X
i
i
=
1
n
∑
x
i
=
i
1
where
X
=
------------- -
N
N : number of measurements of the population
DELTA4000/5000/4D/5D
–
X Tolmin
|
〉
--------------------------- -
3σ
n
∑
x
je
=
j
1
=
--------------- -
; n = size of the sample
e
n
×
=
6 s
; IT = Tolerance interval
i
n
∑
x
j
j
=
1
=
x
------------- -
e
N
s
]
p
6159938010-07
≤ ≤
2 e k
, and k is the number of samples.
English
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