Hey everyone, welcome to this lecture, what are control charts as you had studied in the previous lecture, a control chart is one of the primary techniques of statistical process control. A typical control chart is shown here. This chart plots the averages of measurements of a particular metric taken from the process versus time. The chart has a center line and upper and lower control limits UCL and LCL. The center line or CL represents where this metric should fall. If there are no unusual sources of variability or special causes are present.
The upper and lower control limits are determined using a simple formula. The formula to calculate the upper control limit is mean plus three standard deviations The formula to calculate the lower control limit is mean minus three standard deviations. control charts are applied to the output variables in a system. However, in some cases, they can be usefully applied to the inputs as well. The control chart is a very useful process monitoring technique. When special causes are present.
The data points on the control chart will plot outside the control limits. This is a signal that some investigation of the process should be made and corrective action to remove these special causes are taken. Systematic use of a control chart is an excellent way to reduce variation. With that understanding of control charts, it is important to determine the difference between control limits and specification limits. You will learn that in the next lecture. Thank you for attending.
See you in the next one.