1. Overview of Total Quality Tools
Chapter 15
Overview of Total Quality Tools

2. Objectives
After reading the chapter and reviewing the materials presented the students will be able to:
Define total quality tools.
Understand Pareto Charts.
Understand Cause-and-Effect Diagrams.
Understand Scatter Diagrams.
Select the right tools for the job.

3. Pareto Charts
The Pareto chart is a useful tool when you want to separate the important from the trivial (fig 15-1, page 246).
In the real world a minority of causes lead to a majority of the problems. This is known as the Pareto principle.
For example in a factory, of all the problems, only 20% of them will produce 80% of the defects.
Examining the defects we will find that 80% of the defect cost will come from 20% of the cost elements.

4. Cause-and-Effect Diagrams
The cause-and-effect diagram (also called Ishikawa or fishbone diagram) (fig 15-8, page 249) is used to identify and isolate the causes of a problem.
The technique was developed by the late Dr. Kaoru Ishikawa, a noted Japanese quality expert.
The diagrams separate the causes from the symptoms.

5. Check Sheets
In the check sheet shown in fig (page 253) five types of miswire defects are coded by symbols.
A quick glance at the check sheet points to operators 28 and 33 as the sources of the problem.
We do not know the cause at this point, but we know where to start looking.
Check sheets can be valuable tools in converting data into useful easy to use information.

6. Histograms
Histograms are used to chart frequency of occurrence (fig 15-15, page 255).
The histogram is a measurement scale along one axis (usually the X axis) and frequency of measurements on the other.
Histograms tell you whether a process leads to a product that can be accepted or rejected. It cannot give you details of the causes of defects.

7. Statistical 6 σ and popular Six Sigma
% of all sample values will be found between +6σ and – 6σ .
Six Sigma practitioners use % rather than the actual statistical value.
Npmo – non conformances per million opportunities.
Motorola version of Six Sigma quality performance – 3.4 npmo.
3.4 npmo is not close to the statistical pure six sigma rate of .002 npmo.

8. Scatter Diagrams
The scatter diagram is used to determine the correlation (relationship) between two characteristics (variables).
Example: To determine the relationship between automobile fuel consumption and the rate of speed at which people drive, plot mpg on the y-axis and mph on the x-axis. Examination of the data will show a correlation that supports the theses that faster cars travel, the more fuel they use (fig 15-22, page 260).

9. Run Charts and Control Charts
The run chart (trend chart) records the output results of a process over time.
Because one axis (usually the x-axis) represents time , the run chart can provide a picture of what is happening in a process as time goes by.
Control charts: The data are plotted over time just as with a run chart. The difference is that the data stay between the upper control limit (UCL) and the lower control limit (LCL) while varying about the center line or average only so long as the variation is the result of common causes (statistical variations). Whenever a special cause (non statistical cause) impacts the process a penetration of the limits or run of several points above or below the average line, this is the control chart’s signal that something is wrong that requires immediate attention.

10. Stratification
Stratification involves investigating the cause of a problem by grouping the data into categories.
The groups might include the data relative to the environment, the people involved, the machines used in the process, materials, etc.
Grouping data by common elements or characteristics makes it easier to understand the data.

11. Five S
The 5 S’s were originally conceived in Japanese to reduce waste and reduce errors, defects, and injuries. Their translation would be:
1. Sort - Sort useful from useless.
2. Store – Everything in its place.
3. Shine – Workplace and equipment clean.
4. Standardize – Select the best practice.
5. Sustain – Make sure rules are followed.

12. Flowcharts A flowchart is a graphic representation of a process.
A necessary step in improving a process is to flowchart it.
Standard symbols for flowcharts are shown in table 15-1, page 268.
A typical process flowchart is shown in fig 15-33, page 269.

13. Surveys
The purpose of the survey is to obtain relevant information from a cross section of the target population.
Because you design your own survey, you can tailor it to your needs.
Surveys can be conducted internally as a kind of employee feedback on problem areas on products or services.
They can also be conducted with external customers to gain information about your products or services.
Ask the right questions, and test out the survey, before you use it.

14. Failure Mode and Effect Analysis (FMEA)
Failure Mode and Effect Analysis (FMEA) tries to identify all possible potential failures of a product or process, prioritize them according to their risk, and set in motion action to eliminate or reduce the probability of their occurrence.
Design FMEA is employed during the design phase of a product or service.
Process FMEA looks at potential failures of a process.

15. FMEA’s 3 Risk Assessment Factors
FMEA’s 3 Risk Assessment Factors are:
Seriousness to the customer.
Probability of the fault’s occurrence.
Probability of the fault’s detection by the system responsible for defect prevention or detection.

16. Design of Experiments
Design of Experiments (DOE) is a very sophisticated method for experimenting with processes with the objective of optimizing them.
If you deal with complicated processes that have multiple factors affecting them, DOE may be the only practical way of bringing about improvement.

17. Summary
The Pareto chart is a useful tool when you want to separate the important from the trivial. In the real world a minority of causes lead to a majority of the problems. This is known as the Pareto principle. For example in a factory, of all the problems, only 20% of them will produce 80% of the defects.
The cause-and-effect diagram (also called Ishikawa or fishbone diagram) is used to identify and isolate the causes of a problem. The technique was developed by the late Dr. Kaoru Ishikawa, a noted Japanese quality expert. The diagrams separate the causes from the symptoms.
Check sheets can be valuable tools in converting data into useful easy to use information.
Histograms are used to chart frequency of occurrence.
Npmo – non conformances per million opportunities. Motorola version of Six Sigma quality performance – 3.4 npmo. 3.4 npmo is not close to the statistical pure six sigma rate of .002 npmo.
The scatter diagram is used to determine the correlation (relationship) between two characteristics (variables).
The run chart (trend chart) records the output results of a process over time.
Control charts: The data are plotted over time just as with a run chart. The difference is that the data stay between the upper control limit (UCL) and the lower control limit (LCL) while varying about the center line or average only so long as the variation is the result of common causes (statistical variations).
Stratification involves investigating the cause of a problem by grouping the data into categories.
A flowchart is a graphic representation of a process.
The purpose of the survey is to obtain relevant information from a cross section of the target population.
Failure Mode and Effect Analysis (FMEA) tries to identify all possible potential failures of a product or process, prioritize them according to their risk, and set in motion action to eliminate or reduce the probability of their occurrence.
Design of Experiments (DOE) is a very sophisticated method for experimenting with processes with the objective of optimizing them.

18. Home Work Answer Questions 1, 2, 7 on page 276.
1. Explain the purpose of the Pareto chart. Give an example of when one would be used.
2. Describe the origin and use of the cause-and effect diagrams.
7. Explain the purpose of the scatter diagram. Give an example of how one would be used.