On process capability and product tolerancing as affected by measuring device

Statistical process control seeks to monitor the quality characteristics stipulated in the product design specifications to assure that these are achieved by the operation. Measuring devices are subject to variations but usually the possibility of obtaining fluctuating results is often neglected and the measurements provided by these devices are taken for granted as true values. Presents, briefly, process control and shows the interaction between process capability and measuring device error. Presents a model for determining process target limits which minimize cost of production taking into account measuring device variability. Provides a criterion for establishing optimal process capability as well.