Construction of Control Charts Based On Six Sigma Initiatives for the Number of Defects and Average Number of Defects per Unit

A control chart is a statistical device used for the study and control of a repetitive process. In 1931, Shewart suggested control charts based on 3 sigma limits. Today manufacturing companies around the world apply Six Sigma initiatives, with a result offewer product defects. Companies practicing Six Sigma initiatives are expected to produce 3.4 or less number of defects per million opportunities, a concept suggested by Motorola in 1980. If companies practicing Six Sigma initiatives use control limits suggested by Shewhart, then no points will fall outside the control limits due to the improvement in the quality of the process. ASix Sigma based control chart is constructed for the number of defects and average number of defects per unit. Tables are providedto aid engineers in decision making.