Abstract
Depending on types of yarn and technology used, there are numerous process points and quality characterisics to be controlled by sampling process control in the textile yarn industry. In all of these control stages, sampling interval may change drastically, say, from the quarter hour to 10,000 h. Therefore, determining optimum sampling interval in all process stages of yarn spinning is a very important issue from the points of production cost and quality of yarn. This article presents how to solve this issue by means of Duncan's economic and statistical control chart design model. The data needed for Duncan's model, such as cost and time, have been provided by an integrated textile plant.