If the difference between the minimum and maximum value of a parameter is large, the values being tested can be further apart or more values can be tested. If the range of a parameter is small, then less values can be tested or the values tested can be closer together. Typically, the number of levels for all parameters in the experimental design is chosen to be the same to aid in the selection of the proper orthogonal array.
Number of Factors Number of Levels Orthogonal Array Selector 38
General Guidelines 39 1. Good understanding of the problem Research has shown that one of the key reasons for an industrial experiment to be unsuccessful is due to lack of understanding of the problem itself. The success of any industrially designed experiment will heavily rely on the nature of the problem at hand. The success of the experiment also requires team effort.
General Guidelines 40 2. Conduct a thorough and in-depth Brainstorming Session The successful application of DOE requires a mixture of statistical, planning, engineering, communication and teamwork skills. Brainstorming must be treated as an integral part in the design of effective experiments. It is advised to consider the following key issues while conducting brainstorming session: Identification of the process variables, the number of levels of each process variable and other relevant information about the experiment Development of team spirit and positive attitude in order to assure greater participation of the team members. How well does the experiment simulate users ’ environment? Who will do what and how? How quickly does the experimenter need to provide the results to management?
General Guidelines 41 3. Select the appropriate response or quality characteristic A response is the performance characteristic of a product which is most critical to customers and often reflects the product quality. It is important to choose and measure an appropriate response for the experiment. The following tips may be useful to engineers in selecting the quality characteristics for industrial experiments. Use responses that can be measured accurately. Use responses which are directly related to the energy transfer associated with the fundamental mechanism of the product or the process. Use responses which are complete, i.e., they should cover the input- output relationship for the product or the process.
General Guidelines 42 4. Choose a suitable design for the experiment The choice of an experimental design will be dependent upon the following factors: Number of factors and interactions (if any) to be studied Complexity of using each design Statistical validity and effectiveness of each design Ease of understanding and implementation Nature of the problem Cost and time constraints
General Guidelines 43 5. Perform a screening experiment A screening experiment is useful to reduce the number of
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- Spring '19
- Magdy Khalaf
- Fractional factorial designs, Factorial Designs