Journal of Engineering Research

, 3:16

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

Variation source identification of multistage manufacturing processes through discriminant analysis and stream of variation methodology: a case study in automotive industry

  • Aliasghar BazdarAffiliated withDepartment of Industrial Engineering, Faculty of Engineering, Golpayegan University Email author 
  • , Reza Baradaran KazemzadehAffiliated withDepartment of Industrial Engineering, Faculty of Engineering, Tarbiat Modares University
  • , Seyed Taghi Akhavan NiakiAffiliated withDepartment of Industrial Engineering, Sharif University of Technology


Product quality problem is a critical issue for multistage manufacturing processes, especially in continuous production lines whereby quality characteristics are measured at the end of the line. Therefore, it is important to reduce process variation by identifying its sources and eliminating its causes. In this regard, a novel approach, to identify the source of variation in multistage manufacturing processes through integration of the Fisher’s linear discriminant analysis and the stream of variation methodology, is proposed. Linear discriminant analysis is used to separate the variation of quality characteristics through the different stages of the manufacturing processes while the stream of variation methodology is used for variation propagation modeling in multistage manufacturing processes. Finally, the future deviation is assigned into the analysis, in order to identify the source of variation. With an illustrative case study, it is concluded that the proposed approach improves fault diagnosis of continuous production lines in multistage manufacturing processes.


Discriminant analysis machining process state space model stream of variation variation source identification