Homework

1. The natural average time to laminate a single panel in a circuit board plant is 2 minutes with a natural SCV of 0.5625.

a) Suppose the mean time to failure of the laminate machine is 60 hours and the mean time to repair is 2 hours with an SCV of 1. What is the effective mean process time and its SCV?

b) Suppose you could reduce the average time to repair to only 1.5 hours (still with SCV = 1). Now what is the effective mean process time and its SCV?

c) Suppose for the same cost of decreasing the average time to repair from 2 to 1.5 hours (what you just did in part b), you could instead increase the average time to failure from 60 hours to 81.33 hours. (This will give you the same Availability as in part b, A = 0.976.) Without making any calculations (think about the Tortoise and the Hare machines), would you expect this change to result in a better or worse SCV of effective process times than what you found in part b? Justify your answer.