Design of Q control charts for assuring predetermined process quality

Aiming at monitoring processes in the early phases of long-run mass-manufacturing,a new quality-oriented Q control chart was presented based on the predetermined quality target.In order to assure the designated process quality in short production runs and in the early phases of long-run designated process quality,the main approach was to monitor processes combining the quality-oriented statistical tolerance technique with a Q control chart.The statistical tolerance(C*P,k*) was established based on the predetermined quality target,and the statistical tolerance(C*P,k*) was turned into the judgment condition of the estimate of CP and k based on the given confidence probability.The case study shows that the quality-oriented Q control chart can assure process quality with preset confidence probability under the condition that the process is in the controlled state.