Refined quality control speeds up production

This is a concise explanation of what constitutes control of quality in manufacture, the concept and measurement of collective quality, statistical measures of dispersion in quality, and the preparation and use of quality control charts. A typical chart is discussed with special reference to the distinction between control and specification limits, the initial selection and subsequent revision of control limits, and the utility of control charts in discriminating between variations which are and those which are not due to assignable causes. Attention is drawn to the value of quality control in improving customer relations and in obtaining best results from available manufacturing equipment.