A control chart is an important aid or statistical device used for the study and control chart of the repetitive Process. Control charts were developed by Dr. W. A. Shewhart it is based upon the fact that variability does exist in all the repetitive processes. With the help of a Control chart it is possible to find out the natural capability of a production process, which permits better decision on engineering tolerances and better comparison between alternative designs and also between alternative production methods. There are many types controlled chart designed for different control situations, each with its own advantages and disadvantages and with its own field of application. It consist of graph with central line denoting the target value or standard and two limit line and either side of the central line called ¿upper control limit¿ and ¿lower control limit¿. Quality measured periodically is plotted on the format of chart and status of control assessed. Format of control chart is shown in figure.