Investment in Process Control Justification for Multi-stage Systems Using Analytical Model

Open Access
Buqammaz, Mohammed Khaled
Graduate Program:
Industrial Engineering
Master of Science
Document Type:
Master Thesis
Date of Defense:
Committee Members:
  • M Jeya Chandra, Thesis Advisor
  • Process Control
  • Control Charts
  • Net Present Value
Process control and quality assurance are the composing elements of a quality management system that are used to ensure the quality of a product or a service. It is widely acknowledged that quality management systems improve the quality of the products and services produced. For the purpose of this research, the effect of process control element is investigated. Investment in process control activities is categorized under prevention cost section of the four quality costs categories. The investment in preventive activities assists to reduce the variance and deviation of the mean from the target value of the quality characteristic. The main objective of this research is to quantify the effect of process control in a multi-stage system. The justification of investment in process control activities is based on analytical models, without and with process control, that evaluate costs affected by the presence of process control methods in a multi-stage systems, and these models help us to make optimal decisions. In this research, the X ̅ chart will be used as the process control method, where several selected costs will be evaluated. The Net Present Value (NPV) method is used to compare the costs of a system without process control with those of a system with process control. The fully developed analytical model including various costs is given in chapter two. In chapter three, numerical examples are provided to illustrate the implementation of the model. Finally in chapter four, conclusions and recommendations are presented.