Kaizen
Total quality management
PDCA
source: wiki
Wednesday, 27 January 2010
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Tuesday, 21 July 2009
"The Old Seven."
"The First Seven."
"The Basic Seven."
Quality pros have many names for these seven basic tools of quality, first emphasized by Kaoru Ishikawa, a professor of engineering at Tokyo University and the father of “quality circles.”
1. Cause-and-effect diagram (also called Ishikawa or fishbone chart): Identifies many possible causes for an effect or problem and sorts ideas into useful categories.
2. Check sheet: A structured, prepared form for collecting and analyzing data; a generic tool that can be adapted for a wide variety of purposes.
3. Control charts: Graphs used to study how a process changes over time.
4. Histogram: The most commonly used graph for showing frequency distributions, or how often each different value in a set of data occurs.
5. Pareto chart: Shows on a bar graph which factors are more significant.
6. Scatter diagram: Graphs pairs of numerical data, one variable on each axis, to look for a relationship.
7. Stratification: A technique that separates data gathered from a variety of sources so that patterns can be seen (some lists replace "stratification" with "flowchart" or "run chart").
Excerpted from Nancy R. Tague’s The Quality Toolbox, Second Edition, ASQ Quality Press, 2004, page 15.
What?
The name "Pareto" is derived from the name of founder of the theory "Vilfredo Pareto" on which Pareto chart works. Vilfredo Pareto was an economist who gave the theory that in certain economies the majority of the wealth is held disproportionately by a small segment of the population.
The Pareto principle was brought in Quality by Joseph M. Juran. The Pareto chart is a quality tool that is mainly used to graphically segregate out the "Vital few from Trivial many". The Pareto principle is based on 80/20 rule which states that 80% of the problem are due to 20% of the causes.
The figure given below represents the Pareto diagram/Chart. The first three defects represent the vital defects as they constitute 80% of the total defects.
How?
Step 1 - Categorize the data (e.g. by defect type)
Step 2 - Determine the way to compare relative importance (e.g. it can be on financial basis, frequency basis)
Step 3 - Rank the categories from most important to least important
Step 4 - Find the percentage frequency for each category.
Step 5 - Compute the cumulative frequency in the order they are ranked
Step 6 - Plot bar graph showing the relative importance of each category in descending order.
Step 7 - Identify the vital few by the 80 - 20 rule.
Ground Rules?
Percentage: In the bar graph percentage and not the actual value has to be plotted
Cumulative: The 80% has to be considered for the cumulative percentage. It is not that accurately 80% has to be taken, something less or graeter can also be taken
Merits?
It helps in prioritizing the problem and help management identify the problems that require immediate attention
Pareto chart can also be used to compare the condition before and after the implementation of solution for improvement
"After" improvement Pareto chart can be used to see the impact of the remaining problems
Pareto Chart helps the management in allocating the limited resources to problem solving
Demerits?
Monday, 20 July 2009
Ishikawa diagrams (also called fishbone diagrams or cause-and-effect diagrams) are diagrams that show the causes of a certain event.
A common use of the Ishikawa diagram is in product design, to identify potential factors causing an overall effect.
For more info see here
Wednesday, 15 July 2009
FMEA (Failure mode and effects analysis) is a part of DMAIC in Six Sigma
Is a step after C&E Matrix ant it is used for analysis of potential failure modes within a system
Every defect is measured by Severity, Occurrence and Detection. The multiplication of these elements gives the Risk prioritization (Risk Priority Number RPN) for every case.
Uses of FMEA
- Development of system requirements that minimize the likelihood of failures.
- Development of methods to design and test systems to ensure that the failures have been eliminated.
- Evaluation of the requirements of the customer to ensure that those do not give rise to potential failures.
- Identification of certain design characteristics that contribute to failures, and minimize or eliminate those effects.
- Tracking and managing potential risks in the design. This helps avoid the same failures in future projects.
- Ensuring that any failure that could occur will not injure the customer or seriously impact a system.
- To produce world class quality products
Advantages
- Improve the quality, reliability and safety of a product/process
- Improve company image and competitiveness
- Increase user satisfaction
- Reduce system development timing and cost
- Collect information to reduce future failures, capture engineering knowledge
- Reduce the potential for warranty concerns
- Early identification and elimination of potential failure modes
- Emphasis problem prevention
- Minimize late changes and associated cost
- Catalyst for teamwork and idea exchange between functions
- Reduce the possibility of same kind of failure in future
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