Question

The specification for the diameter of the shaft used in a particular product are 17 cm ± 0.6 cm. The process that produces this shaft is known to be in a state of statistical control and to operate with a mean of 17.14 cm with a standard deviation of 0.2 cm. What is the Cpk for this process?

Answer 1

Cpk= 1.33

Step-by-step explanation:

Upper tolerance limit = 8.5 cm

Lower tolerance limit = 7.5 cm

Cpu = (Upper tolerance limit-mean)/(3*standard deviation) = (8.5-7.98)/(3*0.12) = 1.44

Cpl = (mean - Lower tolerance limit)/(3*standard deviation) = (7.98-7.5)/(3*0.12) = 1.33

Cpk = Min (Cpu,Cpl) = 1.33