Version 1.0, August 31, 2001, Copyright, Hugh Jack 1993-2001

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

  1. APPROACH - Use a Cause and Effect Diagram

 

· The cause and effect diagram was developed by Kaoru Ishikawa in 1943.

  1. - 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.

 

 

· For manufacturing there are some more standard causes to consider.

 

 

· How can a CE diagram be made up?

  1. - use a team for more ideas
  2. - use brainstorming techniques

 

· Brainstorming is a two stage process

  1. 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!!!
  2. 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?

  1. - Post it in visible spots for common reference by all the workgroups.
  2. - Use it to anticipate, or find the cause of problems.
  3. - Keeps workers involved and informed.

 

· Advantages of CE diagram

  1. - Analysis - allows tracking of errors, efficient use of resources, lower costs.
  2. - Elimination of unwanted causes.
  3. - Standardization of existing and proposed operations.
  4. - Education and training to allow personnel to make decisions and correct problems autonomously.

 

6.1.1 Process Diagrams