Quality control analysis of tube drain production at Samba Moda Utama Inc. using robust control chart based on Winsorized modified one-step M-estimator (MOM)

Samba Moda Utama Inc. is one of the automotive component manufacturers focusing on Tube Drain production. As a component manufacturer trusted to meet the demand for vehicle components, Samba Moda Utama Inc. must maintain and improve product quality by doing quality control. The study was conducted on three quality characteristics related to Tube Drain specification parameters that are thought to be related to each other, the outer diameter, inner diameter, and length of the Tube Drain. Using data in which the variability process has been controlled, mean process control uses the Hotelling's T2 control chart, MEWMA, robust Hotelling's T2, and robust MEWMA control chart based on Winsorized Modified One-Step M-estimator (MOM). The performance of these four control charts was then compared. Robust control charts, both Hotelling's T2, and MEWMA, can better detect out-of-control because parameters are estimated from data that has already cleared from outliers, which produce more sensitive control charts. Multivariate measurement of the process capability is carried out through the MCp and MCpk indices. Process capability indices are obtained by considering the correlation between quality characteristics based on the Principal Components Analysis (PCA). Using two components based on the results of the scree plot, it was concluded that the three quality characteristics selected in the Tube Drain production at Samba Moda Utama Inc. had met the specifications determined by the company.