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6. DETERMINING CAUSES OF PROBLEMS
•Can be done by an individual, or a team
•Can be done by
-looking at problems
-thinking about process
6.1 CAUSE AND EFFECT DIAGRAMS
•Consider a production team about to launch a new product. They must anticipate factors that will affect the final product
APPROACH - Use a Cause and Effect Diagram
•The cause and effect diagram was developed by Kaoru Ishikawa in 1943.
-Commonly called - Cause and Effect (CE), Ishikawa Diagram or Fishbone diagram
•In quality we use these to find factors that have some role in a good/bad quality.
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motor size |
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top speed |
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road size |
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congestion |
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handling |
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suspension |
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Driving Time
scenery
accidents
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**Think about how some of these factors will change the driving time, also consider that long driving times can be good, as well as short driving times.
•For manufacturing there are some more standard causes to consider.
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people |
materials |
work methods |
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one quality
environment |
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equipment |
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measurement |
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causes |
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•How can a CE diagram be made up?
-use a team for more ideas
-use brainstorming techniques
•Brainstorming is a two stage process
Step 1: As a group, have each team member contribute ideas. If an idea is not good it doesn’t matter. Add ideas to the diagram. Exhaust all ideas! NO CRITICISM!!!
Step 2: Review the diagram critically as a group. Voting will help to narrow down what are the most important factors.
•What use is a CE diagram?
-Post it in visible spots for common reference by all the workgroups.
-Use it to anticipate, or find the cause of problems.
-Keeps workers involved and informed.
•Advantages of CE diagram
-Analysis - allows tracking of errors, efficient use of resources, lower costs.
-Elimination of unwanted causes.
-Standardization of existing and proposed operations.
-Education and training to allow personnel to make decisions and correct problems autonomously.
6.1.1 Process Diagrams
• Another type of CE diagram is the Process-Analysis diagram. This is used when there are a number of operations or factors involved.