7 Quality control tools(7QC)

          7 Quality control tools(7QC)

Why we need these tool in Quality department.
Firstly we will discuss about it .
7 Quality control tool is help us to solve our daily work with easy and systematic way.
A Japanese engineer Kaoru ishikawa developed these tool.

1. Check sheet 
2.  Histogram
3.  Fish bone diagram / Ishikawa diagram 
4. Control chart 
5. Scatter diagram 
6. Process flow diagram                            
7. Pareto Chart

1. Check sheet

Check sheet is a document ,which is used for stored our information or data or reading of any product or part or any process data.

Check sheet 

Requirements of Quality control/Assurance

2. Histogram

Histogram shows us to variation within process. In histogram we show the frequency distribution in height .
Exactly when we have a lots of data we can't show some particular variation at a point then we use histogram, mainly it is a graphical representation of variation distribution.
It looks like a bar chart but it is different from bar chart, Maine difference between bar chart and histogram is..
In bar chart there is gap between to bars but there between no gap in bars in histogram.

Histogram 

3.Fish bone or Ishikawa diagram 

It is a very important tool of find out the potential causes. It is also called cause & effect diagram.its shape is like a fish due to it is called fish-bone diagram.
Today it is used in automotive as well as not automotive industry.

Fish-bone diagram 

4. Control chart

Control chart is a graphical representation of process variation respect to time interval.
Basically we measure the variation between upper control limit and lower control limit.
There is a two types of control chart, control chat for attributes and control chart for variables.

Control chart 

5. Scatter diagram

We can analyze the degree of relationship between independent and dependent variables through Scatter chart.

Scatter diagram 

6. Process flow diagram
Process flow diagram is basically shows us to flow of any process or product in a plant.
It is also called PFD. In this diagram we show the all process step by step, some symbols is used in it like .
If we will want to understand with an example.  If any company manufactures a piece of metallic sheet ,then firstly we buy a raw sheet then we cut the of sheet then we give a shape as per drawing then we after complete the all manufacturing process now we start the packing of in now we deliver this product so their all the process which are taken on the product before delivery, these steps are consider in process flow diagram.
It is helps us to find out the value added activities or non-value added activities.
Some symbols are refer for these ..
Rounded rectangle shows for starts or end point.
Rectangle shows for operation or any activity.
Diamond shows for decision or conditions.
And inverted triangles for storage.

Process flow diagram 

7. Pareto diagram
One of the most important tool of 7 QC is Pareto chart. It is basically line and bar chart mixed , it also called 80:20 rules diagram means 80 percent problem  generate by the 20 percent of cause or defect.

Pareto chart 

Quality control/Assurance you can check this link for better