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Make A Pareto Chart

A Pareto diagram is a diagram categorizing the number of cases of occurrence (or the amount of loss) of nonconformity and number of nonconformity into items and showing them in descending order. We can find out which item has the problem and how much the impact has spread for the detected defects. There are seven steps to make a pareto chart. There are also different fators or items to be considered to make a Pareto chart

The following steps are guidelines to make a pareto chart:

1. Determine the necessary fields or items.
a. Items relating to the results of defects - type and location of defect, date/period, shift, type of product, etc.
b. Items relating to causes - raw material, components, method of manufacturing, worker, machinery, equipment, etc.)

2. Define a period for data collection.
a. Record the conditions/fields in detail (this information can be used for other tests.
b. Make and use a check sheet for recording data.

3. Fill in the data table.
a. Organize the data according to the type of item (defect) and arrance the items in descending order.
b. calculate the accumulated number, ratio and accumulated ratio, as well as totals.

4. The X represents the type of item and the Y axis the number of defects (failures).
a. Make a scale and the unit of measure for the data on the Y axis.
b. Arrange the items (defect) on the X axis so that the length of X axis approximately equals that of the Y axis.

5. Make a bar and line graph.
a. The bar graph represents the type of defect, and the line graph (called a Pareto curve) represents the accumulated ratio (%).
b. Arrange the type of defects in descending order from left. Place "Others" at the far right.

6. Make a scale for the accumulated ration on the Y axis.
a. Set the maximum level (100%) of the accumulated ratio equal to the sum of defects (failures).

7. Write necessary information into the Pareto Diagram.
a. Also write information about who, when, and for what purpose the Pareto Diagram was created.

Note: Write other information such as the number of data, purpose, period used for data collection, date of creation, name of person who recorded the data.

Through Pareto diagram, it can be identified which types of defects are dominant, select targets for improvement, narrow down the targets, identify the results of improvement, Pareto diagram can be more useful for the analysis than the review of results, and understand the nature and pattern of problems.

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