Goal setting with Six Sigma mean shift determination

A comprehensive approach to quality goal setting is presented that is consistent with Motorola's six‐sigma metric development. In particular, process mean shifts are determined and incorporated into the goal setting process. Methodology includes basic probability theory, statistical control charts, and capability indices. Data for an aircraft part consisting of hundreds of laser‐drilled holes are used to illustrate the procedures. As a result of applying the methods, quality goals are customized based on the number of opportunities for defect, the target end‐product quality level, and the mean shift shown to exist for the processes involved in the product's manufacture. The methods described overcome the mistakes implicit in blindly conforming to the standard six‐sigma goal of 3.4 defects per million.