Determining the contribution of uncorrelated components of product quality variability using a nonlinear functional function for the components
Volume 4, Issue 1, Summer 2014, Pages 1-13
Amir Bahadur Amir Hosseini, Siddique Raisi
Abstract Dispersion is the enemy of quality and an inherent and integral part of manufactured products. Therefore, identifying critical components and their contribution to total variation is an important engineering task, and measuring it in general without the most restrictive assumptions is very complex. The present article presents a systematic approach that can identify the contribution of each component to the total variability in a complex system, in proportion to the type of mechanism of action of the components. The index introduced in this study determines the contribution of the components and can be used as a measure of the criticality of the components of a system. The application of the proposed method in this article does not require any assumptions regarding the linearity of the functional function of the components or the normality of the statistical distribution of the quality characteristics, and includes the analysis of all systems with uncorrelated components. The proposed solution can be used as a powerful tool in the analysis phase of Six Sigma and Lean Six Sigma, and with its help, it is possible to prioritize and policy the use of resources in order to reduce process dispersion. To understand the proposed method in more detail, two well-known examples in industrial engineering are described.
Integration of Six Sigma Methodology and Discrete-Event System Simulation for Quality Improvement and Reduction of Cold Material in the Smelting Plant of Sarcheshmeh Copper Complex
Volume 2, Issue 3, Summer 2012, Pages 142-152
Rasoul Nouralsana, Sajjad Rezaeian, Hassan Jahanshahi, Hamidreza Izadbakhsh, Mahdi Memarzadeh
Abstract Six Sigma methodology has been established as a process-oriented approach with strong emphasis on results and effectiveness, aiming to improve the quality of products, services, and processes. In our country, in line with global developments, industrial and service organizations have rapidly become aware of the high potential of this methodology through information exchange with international organizations and industrial centers, and have been encouraged to implement it. The main objective of this methodology is the implementation of a measurement-based strategy focused on process improvement and variability reduction. Sarcheshmeh Copper Complex, as one of the major and foundational industries of the country, has defined numerous Six Sigma projects to improve production processes, reduce waste, and increase productivity, achieving extensive benefits such as improvement of production processes, reduction of losses and scrap, and significant financial savings. Since one of the main concerns of managers at the Sarcheshmeh Copper Complex is reducing the amount of cold material produced in the smelting plant and consequently preventing the waste of a considerable portion of incurred costs a Six Sigma project was therefore considered to address this issue. In this research, simulation tools were also utilized to develop an integrated model for reducing cold material in the smelting process. For this purpose, a discrete-event system simulation approach was employed. The design and implementation of the simulation model were carried out using Arena software and Visual Basic.