RIASSUNTO
Abstract
One of the fundamental requirements for success in making a process function under the concepts of Total Quality Management is to ensure that it is capable of operating with a minimum variability with respect to the quality specification objectives of the products which are produced by the process.
Quality may be broadly defined in many ways, but from a strictly technical viewpoint Quality Engineering must be understood as the skill to reduce systematically the variability of the processes. It is in this context in which the Continuous Improvement Tools and particularly the Statistical Process Control, are essential for achieving World Class Quality Management.
A program for the application of these tools can detect assignable causes, limit waste, improve the quality of the products, reduce or eliminate reprocessing and, even more important, establish a new process of systematic work toward continuous improvement.
The present job shows both theoretically and practically how to apply these tools to solve quality deviations.
Case Study: Improvement of Jet A1 quality in a Hydrocracking unit.
Background
During the last few years quality systems have become established as a fundamental part of business strategies to increase the productivity and competitiviness of companies. Total Quality Managements focus their attention on their most precious treasure : ""THE CUSTOMER"". If a product is to meet the client s acceptability criterion its quality must inexorably be stable and reproducible, although even then there is no total guarantee that the product will have the same quality. All processes have a certain degree of variability : when the latter is ""natural"" it is due to the cumulative effect of small effects which are known as ""inevitable causes"". In Statistical Control jargon this is referred to as a system of accidental or random causes.
A system which performs with only accidental causes is said to be under ""Statistical Control"".
On the other hand if ""assignable causes"" appear in a process, that is, those that derive from a perfectly detectable source of lack of control, then the use of the continuous improvement tools is fundamental for their correction.