The application of cause and effect diagram in the oil industry in Iran: The case of four liter oil canning process of Sepahan Oil Company

Manufacturing is currently being used as a continuous quality improvement tool, providing a planning, implementing, monitoring and evaluating framework for the quality improvement measures on a sustainable basis. A cause-and-effect diagram, also known as an Ishikawa diagram or fishbone diagram, is often used in quality management in manufacturing industries. Fishbone diagram (also known as Ishikawa diagram) was created with the goal of identifying and grouping the causes which generate a quality problem. Gradually, the method was used also to group into categories the causes of other types of problems which confronted an organization. This made fishbone diagram to become a very useful instrument in the risk identification stage. In this paper, the six sigma technique and cause-and-effect diagram is used to demonstrate how to relate potential causes of a major presenting problem in Sepahan Oil Company. For this purpose, the four liter production line of the company has been selected for investigation. The findings imply that the application of cause-and-effect diagram has reduced the scraps from 50000 to 5000 ppm and has resulted in a 0.92% decrease of the oil waste.