Process Monitoring with Individual Measurements: A Case Study in Corrugated Cardboard Industry

Monitoring production processes with statistical process control charts can provide useful information about the process. This application aims to reveal whether the production process is in control in terms of the data of the bursting strength through exponentially weighted moving average (EWMA) and individual-moving range (I-MR) control charts. Both EWMA chart and I-MR charts were created using the bursting strength data provided from an enterprise for a certain period of time. Within the scope of the study, a total of 126 data belonging to the bursting strength were used to create the control charts. In the creating of the EWMA chart, the weighting factor (λ) was chosen as 0.2. The results of all univariate process monitoring tools considered within the scope of the study showed that the production process was out of control in terms of the bursting strength. In other words, EWMA and I-MR charts were able to effectively detect the variations for the data set belonging to the quality variable under study. It was seen that the charts can be applied to the production process as effective signal detection and process control or monitoring tools in terms of the quality variable of interest.