n March 1990, some math instructors and cadets visited Microtome Precision Inc. of

Colorado Springs to help them improve their process capability for manufacturing a

precision Delrin ring used on high speed disk drives. The specifications for the outer

diameter of this ring are 1.5570.001 inches, which is a critical dimension.

In March 1990, some math instructors and cadets visited Microtome Precision Inc. of Colorado Springs to help them improve their process capability for manufacturing a precision Delrin ring used on high speed disk drives. The specifications for the outer diameter of this ring are 1.55740.001 inches, which is a critical dimension. A capability analysis of the process before improvement techniques were implemented yielded the following statistics from 86 runs: x=1.55708, s=0.000493. (Assume that the outer diameter is normally distributed.) a. Calculate the number of defects per million. (Hint: find the probability that a dimeter will fall outside the specifications and multiply this by 1 million.) b. Calculate the process capability index Cpk. (Hint: let o = s.)