ABSTRACT
The process owner can set LAPL and UAPL as simply the boundaries of the region in which it is practical and desirable to hold the process mean. Feigenbaum defines an alternative method in which the process owner sets these to reflect the acceptable nonconforming fraction. The easiest way to deploy this on a spreadsheet is to set the limits as shown in Equation 5.2 but it might be simpler to use wider control limits. Use of the Western Electric zone tests, e.g. the Zone C test that calls eight consecutive points above or below the center line evidence of a process shift, would, however, add a complication. An acceptance sampling chart that seeks to use this test would use instead eight consecutive points above the UAPL or below the LAPL, with those in between counting.
