Can I Summarize Cp and Cpk of all Dimensions

O

oleg_v

#1
hi
i have a part with multiply dimensions to all dimensions a need to do cp and cpk
my question is can i summarize cp and cpk of all dimensions and one cp and cpk to the hole part?


thanks
 
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Miner

Forum Moderator
Staff member
Admin
#3
Why do you want to do this? A single number would be misleading because it would imply a certain level of capability, and not show how bad a single dimension might be. If you want to summarize the indices show the max and min values.
 

Stijloor

Staff member
Super Moderator
#4
Why do you want to do this? A single number would be misleading because it would imply a certain level of capability, and not show how bad a single dimension might be. If you want to summarize the indices show the max and min values.
I propose to exterminate any Cp, Cpk or whatever letter combination is used to indicate "capability." The capability "Magic Wand" does not exist and I do not believe in fairy tales. Too many get too much wrapped up in trying to obtain some magic number to indicate how "good" a process is :mad: while most process are not even in (statistical) control. How about just focusing on improvement?

Stijloor.
 

Miner

Forum Moderator
Staff member
Admin
#5
I propose to exterminate any Cp, Cpk or whatever letter combination is used to indicate "capability." The capability "Magic Wand" does not exist and I do not believe in fairy tales. Too many get too much wrapped up in trying to obtain some magic number to indicate how "good" a process is :mad: while most process are not even in (statistical) control. How about just focusing on improvement?

Stijloor.
Easy Jan,

Put the the gun down, keep your hands where I can see them and back away slowly. :modcop:
 
S

statdoug

#6
One could argue that ISO standards did not strictly mandate the calculation and tracking of capability indices, and yet the fact that so many companies have responded by doing this indicates that it is a product of the systems of ISO certification. It also coincides with the interests of quality personnel who are looking for job security, to develop and implement such a system.
 
T

tbsiva

#8
That does not add any value...What do you infer from the result... If u summarise the cpk values and find that the Cpk values are low, again you have to go back to the individual dimensions to analyse for the improvement actions
 
O

oleg_v

#9
Hi
thanks for your response i think i go for the individual cp/cpk measurement
to be shore that all my dimension in the part is ion control.

thanks
Oleg :agree1:
 

Bev D

Heretical Statistician
Staff member
Super Moderator
#10
One could argue that ISO standards did not strictly mandate the calculation and tracking of capability indices, and yet the fact that so many companies have responded by doing this indicates that it is a product of the systems of ISO certification. It also coincides with the interests of quality personnel who are looking for job security, to develop and implement such a system.
The Cp/Cpk craze comes more from the automotive industry than ISO.
 
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