Six Sigma evaluation using process capability and X control chart for reducing variance in oil density characteristic: a study in Yemen Online publication date: Thu, 21-Dec-2017
by Faisal A.M. Ali; Amran Ahmed
International Journal of Quality Engineering and Technology (IJQET), Vol. 6, No. 3, 2017
Abstract: This paper presents Six Sigma evaluation based on process capability with X control chart to reduce variations in the oil density characteristics in an oil refinery process in Aden, Yemen. Twenty-five oil density samples with normal distribution were randomly collected, and each sample consisted of four items. Analysis indicated that the levels of sigma employed in Aden refinery are less than 3 σ. The results of this study suggested that the X chart based on six sigma estimation method is significant to reduce variance in the oil density characteristic. In addition, the sigma levels increase when the process capability increases. Thus, the increment in sigma levels leads to improvements in the performance of the process refinery of oil density characteristic. Finally, this paper provides the necessary fundamentals and knowledge for quality control researchers and engineers to reduce variances by using Six Sigma.
Existing subscribers:
Go to Inderscience Online Journals to access the Full Text of this article.
If you are not a subscriber and you just want to read the full contents of this article, buy online access here.Complimentary Subscribers, Editors or Members of the Editorial Board of the International Journal of Quality Engineering and Technology (IJQET):
Login with your Inderscience username and password:
Want to subscribe?
A subscription gives you complete access to all articles in the current issue, as well as to all articles in the previous three years (where applicable). See our Orders page to subscribe.
If you still need assistance, please email subs@inderscience.com
Our Blog 
Follow us on Twitter 
Visit us on Facebook