The field of quality has undergone significant changes as reflected by changes in its definition, paradigms, approaches, techniques, and scope of application. Changes in customer expectation have driven the changes in the technology of design and manufacturing, which is becoming more important in satisfying individual customer expectations. This also calls for special attention to the engineering aspects of quality, which is quality engineering. Quality engineering is an interdisciplinary science which is concerned with not only producing satisfactory products for customers but also reducing the total loss (manufacturing cost plus quality loss). Thus, quality engineering involves engineering design, process operations, after sales services, economics and statistics. This book tried to cover application of Taguchi's method of quality engineering for optimum setting of process parameters for the plastic production so that variation of performance from target value could be minimized.Plastic factory was used as a case company to show the application of Taguchi's methods (design of experiment) together with loss function.