DEK高级培训资料.pdf - 第214页

Cp Cp = T OLERANC E RANGE P A TTERN WIDTH = T OLERANC E RANGE = 24 = 2Cp  = 2 = 8 Shifted Process Capability (Cpk) Issue 2: July 2007 = T OLERANC E RANGE 6 x stdev = 24 12 = 2Cp 12 -12 0 Dist. fr om Mean to near est Lim…

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Cp
Cp =
TOLERANCE RANGE
PATTERN WIDTH
=
TOLERANCE RANGE
6 x stdev
=
24
12
= 2Cp
= 0
-12
12
0
= 2
Process Capability example
Issue 2: July 2007
6 x stdev
12
SIGMA
SIGMA =
SPECIFIED LIMIT
STANDARD DEVIATION
=
12
2
= 6 SIGMA
6 SIGMA @ 12 = +/- 6 SIGMA @ +/- 12
-12
12
0
Cp
Cp =
TOLERANCE RANGE
PATTERN WIDTH
=
TOLERANCE RANGE
=
24
= 2Cp
= 2
= 8
Shifted Process Capability (Cpk)
Issue 2: July 2007
=
TOLERANCE RANGE
6 x stdev
=
24
12
= 2Cp
12
-12 0
Dist. from Mean to nearest Limit
3 X Stdev
Cpk =
=
4_
6
= 0.66 Cpk
Cpk
Your turn…!
An archer fires arrows at a target. He performs
with a standard deviation of 2 cm. The size of
the target (tolerance) is +/- 25 cm. Calculate his
Sigma, Cp and Cpk
Issue 2: July 2007
Sigma =
Cp =
Cpk =
25/2 = 12.5
50/12 = 4.17
25/6 = 4.17
50cm