Quality control methods: Towards modern approaches through well established principles

Abstract

Zero-defect quality control (ZDQC) is a result of the interaction of source inspection, poka-yoke devices applied as 100% inspection and immediate corrective action after detecting abnormalities in processing. The aim (ZDQC) is to ensure that a manufacturing system is able to produce defect-free products consistently through identification and control of the causes (errors) of defects. ZDQC has source inspection as its most important component. The identification and control of causes which generate defects are the main points of this inspection method. The effective utilization of source inspection depends on the acknowledgement of the existence of a cause-and-effect relationship between errors and defects, indentification of incidental errors and implementation of suitable techniques to counteract them. The improvement of the inspection process is often mistaken for the improvement of quality control and assurance. Therefore, one might think that sampling inspection is always preferable over 100% inspection. However, 100% inspection performed in a ZDQC environment has proved to be superior to sampling inspection for achieving the goal of zero defect.