Soroush Avakh Darestani - ۱Faculty of Industrial and Mechanical Engineering, Islamic Azad University, Qazvin Branch, Qazvin, Iran
Mina Nasiri - ۱Faculty of Industrial and Mechanical Engineering, Islamic Azad University, Qazvin Branch, Qazvin, Iran

Process capability indices (PCIs) measure actual or the potential performance of process indicators to the target and specification limits. PCIs and control charts can be mentioned as two useful and applicable tools to measure the product quality and process performance. In this research, the fuzzy set theory is used to give more information and flexibility of PCIs. Both triangular fuzzy number (TFN) and trapezoidal fuzzy number (TrFN) are applied in fuzzy theory. The results show that PCIs such Pp as Ppk and are more informative and flexible in fuzzy environment. The proposed methodologies are applied in a first tier supplier for automotive industry in Qazvin’s industrial area of Iran.

Quality; Control Chart; Process Capability Indices; Fuzzy; Statistical Process Control