Using statistical process control

Statistical process control, also referred to as SPC, involves using statistical techniques to measure and analyze the variation in processes. Statistical process control is mostly used in the manufacturing process to monitor the product quality and to maintain processes to fixed targets. Most manufacturing plants use statistical process control to improve the quality of their processes. However, statistical process control is rarely use don its own, most of the time you will find that manufacturing plants use statistical process control in addition to other techniques, such as process improvement plans, variation reduction, and sampling plans.

Statistical process control is going to be used by most manufacturing plants as a way to monitor the consistency of the processes that they use to manufacture a product as designed. The main goal of statistical process control is to get and keep processes under control, regardless of how good or bad the design is of the product being manufactured. All that statistical process control is supposed to do is make sure that the product is being manufactured as intended, by following the design that it is assigned. Statistical process control cannot improve a poorly designed product's reliability, all it can do is maintain the consistency of how the product is made, which is only as good as its designed reliability.

One of the most common tools used for statistical process control is the control chart. The control chart is a graphical representation of the descriptive statistics for certain quantitative measurements of the manufacturing process for a product. How the control chart works is that the statistics are displayed in the control chart in comparison to the "in control" sampling distributions. This comparison is designed to detect any unusual variations in your manufacturing process. If these unusual variations arte detected it can indicate that there is a problem with your process, by knowing what the possible problem is you can take the steps required to correct the problem so that your manufacturing process runs as designed.

The one thing that you need to know about control charts is that several different descriptive statistics can be used in control charts, and several different types of control charts can be used to test for a variety of causes. Control charts can also be used with product measurements to analyze process capability and to make improvements to your processes.

Here is a look at the benefits that using statistical process control can provide for your manufacturing plant.

• Will provide you with feedback on whether or not you are keeping processes in control. It can also provide you with surveillance of the processes, which allows you to see if they are in control or not.


• Will signal you ahead of time if there is a problem with one of the processes, which will give you plenty of time to fix the problem before it gets out of hand


• Detects assignable causes of variation Also detects normal causes of variation.


• Accomplishes process characterization


• Once it has been in play for a period of time it will gradually reduce the need for inspections because it will show you ahead of time what is going on so that you can stop it.


• Can also monitor your process quality, which will alert you to the fact of any improvements that need to be made in your process


• Provides you with the mechanism that you will need to make process changes and to track the effects of those changes


• Once the process is considered stable, meaning you have eliminated all of the assignable causes of variation for the process, it will provide you with the process capability analysis with comparison to the product tolerance