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Quality Devices

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Quality Devices

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  1. Quality Tools Quality Tools - http://www.kwaliteg.co.za

  2. Table of Contents • Quality techniques • 7 Basic Quality techniques • Histograms • Pareto Charts • Run Charts • Scatter Diagrams • Control Charts • Flow Charts • Cause and Effect Diagrams • New techniques • Other Tools Quality Tools - http://www.kwaliteg.co.za

  3. Introduction • In the following we will Examine the Techniques and Tools that Support Quality Management within a company. There are for the 7 Basic Tools which we are going to define. Generally they can be subdivided into: • mathematical statistical Tools • logical tools Quality Tools - http://www.kwaliteg.co.za

  4. Histograms What is it? • A Histogram is a bar graph • usually used to present frequency data How does it Work? • Define Categories for Data • Collect Data, sort them into the categories • Count the Data for each category • Draw the Diagram. each category finds its place on the x-Axis. • The bars will be as high as the value for the category What is its use? • Histograms provide an easy way to evaluate the distribution of Data over different categories USL LSL Quality Tools - http://www.kwaliteg.co.za

  5. LSL USL Histograms Example: take the failure rate of a machine over a period of x weeks. Now Assign every week the number of failures that occurred. Draw the Histogram. Let the bar represent the weeks. The height of the Bar on the y-axis is the number of failures that occurred during that week. Quality Tools - http://www.kwaliteg.co.za

  6. X Type Pareto Charts What is it? • A Pareto Chart is a Histogram • + a cumulative line How does it Work? • Similar like a Histogram • First define categories, collect Data and sort them into the Categories. Count the occurrences for each category. • Now rank the categories starting with highest value. • Draw cumulative points above all the bars and connect them into a line. What is its use? • Pareto Charts are used to apply the 80/20 rule of Joseph Juran which states that 80% of the problems are the result of 20% of the problems. A Pareto Chart can be used to identify that 20% route causes of problem. Quality Tools - http://www.kwaliteg.co.za

  7. Pareto Charts Example: • A certain machine has different kinds of failures that occur. The Maintenance department identifies these types of failures and counts their occurrence over a period of 3 month. The Data is then added up. The Failures are ranked by their occurrence values starting with the most frequently occurring failure. • A histogram is drawn with bars representing the types of failures. Furthermore are cumulative values assigned to the failure types and drawn into the diagram. • Now determine the point were the cumulative line crosses the 80% mark. Concentrate of the failure types that lie left of this mark. Quality Tools - http://www.kwaliteg.co.za

  8. Pareto Charts 100% 50% Percentages of defects found Types of defects Quality Tools - http://www.kwaliteg.co.za

  9. Measurement Time Run Charts What is it? • Run Charts are representing change • in measurement over a sequence or time How does it Work? • Gather Data • Organize Data • Measurements (y) must be confronted with time or sequence of the events. • Chart Data • Interpreting Data What is its use? • Determining Cyclic Events and there average character Quality Tools - http://www.kwaliteg.co.za

  10. Measurement Time Run Charts Example • Oil consumption of a specific machine over a period of time. Quality Tools - http://www.kwaliteg.co.za

  11. Y X Scatter Diagrams What is it? • Statistical tool showing a trend in a series of values. How does it Work? • Gain values series • Draw graph with value points • Draw trend line: m*x+a • Calculate m value • Calculate a value • Calculate points for trend line. What is its use? • Demonstrating correlations between values and showing trends for value changes. Quality Tools - http://www.kwaliteg.co.za

  12. Y X Scatter Diagrams Quality Tools - http://www.kwaliteg.co.za

  13. Y Upper limit Average/Spec Lower limit X Control Charts What is it? • Statistical tool, showing whether • A process is in control or not How does it Work? • Define Upper limit, lower limit and medium value • Draw Chart. • Gather values and draw them into chart What is its use? • Taking samples of a process and detect possibility of process being out of control Quality Tools - http://www.kwaliteg.co.za

  14. Y Upper limit Average/Spec Lower limit X Control Charts Quality Tools - http://www.kwaliteg.co.za

  15. Within Spec? Process Output Input adjust Yes No Flow Charts What is it? • Way of representing a Procedure • using simple symbols and arrows • A Flowcharts shows the activities in a process and the relationships between them. Operations and Decisions can be represented How does it Work? • Determine what Process or Procedure you want to represent. • Start at a certain point and go then step by step using circles or rectangles for operations or other elements, diamonds for decisions, arrows show the flow and the direction. • Document the elements with titles. Let it close with an ending point. What is its use? • A Flow chart lets a process or procedure be understood easily it also demonstrate the relationships between the elements. Quality Tools - http://www.kwaliteg.co.za

  16. start Repair machine No Check machine OK? Yes end Within Spec? Process Yes Input Output No adjust Flow Charts Example: • You intend to repair a certain machine. • First you perform the repair thought to be necessary • Then You check it • If it does not work you continue with repairs • If it works you finish Quality Tools - http://www.kwaliteg.co.za

  17. Cause a Cause b effect Cause c Cause d Cause and Effect Diagrams What is it? • It’s a diagram that demonstrates • the relationship between Effects • and the categories of their causes • The Arrangement of the Diagram lets it look like a fishbone it is therefor also called fish-bone diagram How does it Work? • Determine the Effect or Problem you would like to examine • Categorize the possible causes • find subcategories • Describe the possible causes What is its use? Quality Tools - http://www.kwaliteg.co.za

  18. Cause and Effect Diagrams Machine Man effect Milieu Measurement Method Quality Tools - http://www.kwaliteg.co.za

  19. Thank You Quality Tools - http://www.kwaliteg.co.za