A tube for use in coronary surgery requires a special coatin

A tube for use in coronary surgery requires a special coating. Specifications for this coating call for it to be at least 0.09 millimeters but no more than 0.14 millimeters. Suppose the long-run average of a coating process is 0.11 millimeters Further suppose this process\' standard deviation is 0.01 millimeters. What proportion of the output from this process will fail to meet specification? Process capability: What metric would be used to assess the capability of this process? What\'s the value of this metric? Is this process capable?

Solution

Mean = 0.11 mm

UCL = 0.14 mm

LCL = 0.09 mm

Standard Deviation = 0.01 mm

(1) (B) & (D) is out of Lower limit therefore fails to meet specification.

(2) (B) because Cpk calculation consider mean, Standard deviation, and both limit. It gives the true measure.

(3) (A) C_pk = min{(mean - LCL) / (3 * Std Dev) , (UCL - mean) / (3 * Std Dev) = min{ 0.67 , 1.67} = 0.67

(4) (B) , Normal requireement is Cpk should be atleast 1.33