Question 1 In a precision grinding of a complicated part it

Question 1) In a precision grinding of a complicated part, it is more economical to rework the part than to scrap it. Therefore it was decided to establish the rework percentage at 12.5%. Assuming Normal distribution of the data, and a standard deviation of 0.01mm and an upper Specification limit of 25.38mm : a. Determine the process center

Solution

P(X>25.38)=12.5%

phi((25.38-mu)/0.01)=1-0.125=0.875

(25.38-mu)/0.01=1.15

mu=25.37 mm (process center)