Statistical Process Control (SPC) is a unique method of quality control by observing the manufacturing procedure. We all must have heard about the phrase, ΓÇÿprevention is better than cureΓÇÖ so SPC basically helps an industry to prevent any undesirable outcome. Initially quality check was done after manufacturing and products were collected as sample but now with the help of SPC every step is scrutinized by quality inspector.

Why there is need of Statistical Process Control (SPC)?

Now a day when industries compete to each other for attaining highest market share, the high rates of raw material and costly manufacturing units indirectly put a lot of pressure on the manufacturer to give its best. In such cut throat competition SPC is now much needed as it not only prevents production of sub standard products but it also stops wastage of money and time.

How Statistical Process Control is done?

The function of SPC is done in three phases:

1. Knowing the process.
2. Removing the visible factors that could be the reason for instability in the result.
3. Scrutinizing the process with the help of control charts.

How collect and record data?

The data is initially gathered in the form of manufactured final product. You can say it is the sample that people collect to check the quality. Various kind of data is collected and measured on various scales

SPC is done basically with the help of tools. The tools of statistical process control are run charts, control charts.

Run Charts

Basically run charts are used to collect data within the process of manufacture in the given timeline. They are mostly represented by graphs. These graphs mostly used to see that when the process of manufacturing is going beyond the control line.

Control Charts

These charts are used to identify the uncommon reason for variation the in the process of manufacture and outcome.

After properly scrutinizing the whole process, the manufacturer is then able to get an alert of what are the factors that are causing anomalies in the process.

Before we move on further we must know that the various types of charts are used to identify the reason for variation in the product. There are two reasons for variations, one is common reason and another is uncommon. The common reasons for variations are weather, labor, and humid. The common reasons fall under controlled line in the control chart whereas there are many sudden and special reasons that which can cause variations, these special causes fall below the line.

The sudden reason or special reasons are:

1. Improper raw material
2. Machinery broke down.
3. Improper use of machine.

There are some other types of charts used under control chart to identify the reason for variation and that are as given below.

X-bar- R chart – This bar can only be used if you are gathering data in group of eight or lesser.
X- Bar ΓÇô S chart – This bar can only be used if you are gathering data in group of more than eight sub ΓÇôgroup.

Attribute Data

P-Chart – This chart is for gathering and scrutinizing the number of anomalies in a cluster of parts.
U ΓÇô Chart – This is for recording the anomalies in each separate part.

Before putting into work Statistical Process Control one must go through the above theory as a beginner.