DRVNA INDUSTRIJA, vol.73, no.1, pp.35-46, 2022 (SCI-Expanded)
Statistical process control tools are of great importance in terms of controlling manufacturing processes and improving product quality. In this study, the manufacturing process of medium density fiberboards manufactured in a company operating in the forest products industry was monitored by using multivariate Hotelling T-2 statistical process control chart in terms of some quality characteristics. The T-2 values of the signals detected by the Hotelling T-2 control chart were also decomposed. By the decomposition of T-2 values, it was determined which quality characteristics contributed more to each signal. It was seen that the process was not in control for Hotelling T-2 control chart, which reveals the shift level in the mean of quality characteristics. As a result, the application of Hotelling T-2 allowed fast detection of possible abnormalities in the process. The decomposition of T-2 values successfully revealed which quality characteristics contributed significantly to the signals. Besides, it was concluded that, for monitoring, the Hotelling T-2 chart was able to employ simultaneously different quality characteristics of medium density fiberboard. The current application study also contributed to the emergence of the root causes of the large shifts in the process. In conclusion, the findings of the study enabled the company to ensure the process stability and to facilitate decision-making on actions to be taken for quality improvement.