The 7 QC Tools
Kaoru Ishikawa a professor of engineering at Tokyo University first gives the “7 QC Tools” to world. He is knows as father of “Quality Circle”.
The 7 QC tools developed / originated in japan and also called as seven basics tools.
These 7 tools comprise of graphical presentation such as histogram and statistical techniques like controls charts. The combination of 7 tools useful in solving the quality, production and process related problems.
The 7 QC tools are:
- Check sheet.
- Flow chart
- Cause and effect diagrams.
- Pareto analysis.
- Scatter charts.
- Process control charts.
1) Check sheets:
2) Flow chart:
- This is very basic sheet which after collecting the data shows at what interval data occurs repeatedly.
3) Cause and effect diagrams:
- This gives the basic idea about in what fashion the data we have to collect or how we want to proceed
- This Flow Chart is helpful in DMAIC approach of 6 sigma.
- Some of the 7 QC tools replaces flow chart with “stratification” or “run chart”.
4) Pareto analysis:
- The cause and effect diagram introduced by Kaoru Ishikawa.
- The cause and effect diagram tell us the causes and effects.
- This has to be made by taking help of BRAINSTORMING Session.
- This has been introduced by vilfredo Pareto.
- This is based on 80:20 law.
- 80% of problem caused by 20% of few major factors which are called as Vital Few, whereas remaining 20% of problem is caused by 80% of many minor factors which are also referred as Trivial Many.
- This gives us the idea about the major problems.
- Histogram introduced by Karl Pearson.
- Histogram is a bar graph which represent frequency
- Histogram shows the variation in the data in graphical form.
- We can assess how the variation looks like.
6) Scatter charts:
7) Process control charts
- Scatter Diagram shows the relationships between factors which are taken for evaluation.
- The graph plotted considering dependent variables on Y – Axis and Independent Variable on X – axis
- The relationship between X and Y can be linear, curvilinear, exponential, logarithmic, quadratic, polynomial
- This gives the idea about the variation and tell which variations to control and how?
- In control chart There is central line which is average and above central line. There is line called upper control limit and line below central line is lower control line.