Can Cpk be calculated without tolerances or limits?

Bev D

Heretical Statistician
Staff member
Super Moderator
#11
Cpk is generally the value of the distance from the closest limit to the average divided by 3*SD. In your case the 'closest limit' is the lower limit as its the only limit. Cpk = (Avg-LSL)/3*SD
(this is how unilateral tolerances are supposed to be handled when calculating Cpk)
 
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D

dtchild

#12
You need at least a one sided spec of some sort to give a Cpk. Remember, the capability is what is being gaged and you need to specify WHAT you are capable of doing.
 
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