Ishikawa Diagram
The contributions of the Ishikawa Diagram are numerous for both Industry and Quality
Born in Japan in 1915, with a PhD in Chemical Engineering from Tokyo University in 1939, Kaoru Ishikawa began his career in Quality in 1941 at the Nissan Liquid Fuel Company. His bibliographic production included a total of 647 articles and 31 books, among which some such as “Introduction to Quality Control” and “What is Total Quality Control? The Japanese way”.
His contributions are numerous both for Industry and for Quality, but we cannot fail to mention the dissemination of the Philosophy of Quality, also known as the “Culture of Quality”.
As chairman of the Japanese Committee of the National Conference on Quality Control, Ishikawa dedicated himself to making people and companies aware of the implementation and dissemination of the importance of quality for economic development. In this way, scholars point out its crucial role in the development of quality in Japan, beating or even surpassing North American quality standards.
Quality tools
We cannot leave aside the fact that numerous quality tools were already popular even before Ishikawa’s accomplishments, however, he was concerned with gathering tools that could be used by any collaborator, directing the focus on the practical application of methods and results. . This set of gathered techniques became known as “the 7 tools of Quality”, which is still used on a large scale by several companies around the world.
- Pareto’s chart
- Fishbone Diagrams (Ishikawa Diagram)
- Histograms
- Check Sheets
- Scatter Charts
- flowcharts
- Control Charts
However, as useful as such tools seem to be, you must have a great understanding and knowledge about the problems that exist within your process so that each of these is applied assertively, resulting not only in analysis, but in results. In addition, it is also necessary that a culture of using these tools emerge and also the “Culture of Quality”, because without this, the flow of continuous improvement will not be fed back.
Quality and Ishikawa
Despite all the contributions that Ishikawa left as a legacy for the entire Quality area, we can highlight the Ishikawa diagram, also known as the Fishbone Diagram or even the Cause and Effect Diagram. Simple to create and use, the tool helps organize information to get to the root cause of a problem.
Therefore, such a diagram aims to help the team arrive at the real causes of problems that affect organizational, managerial or even operational processes of a company. That is, the purpose here is to identify which factors result in an undesirable situation in the corporation.
Ishikawa’s method is based on the hypothesis that, for each problem, there is a limited number of primary or principal causes, secondary, tertiary, and so on. And because this method was initially developed for industrial systems, the causes can be grouped into 6 categories, which also bears the name of the 6M Methodology, which are:
- Machine
- problems linked to the failure or inadequacy of the machinery used, such as mechanical problems or improper use.
- Material
- the raw material or the material that was used in the process does not comply with the requirements for carrying out the work, that is, it is outside the necessary specifications to be used, such as a product that is the wrong size, expired or outside the ideal temperature.
- Labor
- Problems may also involve people’s attitudes and difficulties in carrying out the process, and may include: haste, imprudence, lack of qualifications, lack of competence, etc.
- Environment
- In this item, we must analyze the company’s internal and external environment and identify the factors that favor the occurrence of problems, such as pollution, heat, lack of space, layout, noise, meetings, etc.
- Method
- The processes, procedures and methods used during the activities can also influence the problem to occur, that is, we must analyze how much the way of working influenced the problem, for example, if there was planning, if it was executed as planned, if the tools certain were used, etc.
- Measurements
- This category covers causes that involve the metrics used to measure, monitor and control work, such as the effectiveness of calibration instruments, indicators, targets and charges.
How to make?
- Define the problem to be solved;
- Brainstorming with the team assigned to solve this problem, focusing on the question “Why did this problem happen?”, categorizing each of these reasons according to the 6M Methodology;
- Analyze the causes focusing on the question “Why did this cause happen?”, thus creating ramifications of these causes, thus identifying the first sublevel of these causes;
- Analyze data and evidence to validate such statements and/or causes;
- Arriving at a root cause, where all the points listed above can be answered, even if relatively, but thus reaching a root cause;
- Create action plans to eliminate the occurrence of such root cause, because in this way we will be mitigating all the points already analyzed and mainly the general problem, initially named.