A process is in statistical control with x = 202.5 and s = 2.0. Specifications are at LSL = 196 and USL = 206.
(a) Estimate the process capability with an appropriate process capability ratio.
(b) What is the potential capability of this process?
(c) Items that are produced below the lower specification limit must be scrapped, while items that are above the upper specification limit can be reworked. What proportion of the process output is scrap and what proportion is rework?
(d) Because scrap is more expensive than rework, the process has been centered closer to the upper specification limit. If scrap is twice as expensive as rework, is the process mean at the best possible location? What value of the process target would you recommend?