To Conduct a Single type of Statistical Design Study

◦ Design Variables—Displays the design variables obtained from an existing MODS along with their mean values, the statistical distribution type assigned to the design variables, and the distribution parameters calculated for the design variables. The design variables are listed in separate rows.

◦ Design Goals—Displays the design goals obtained from an existing MODS along with their minimum and maximum values, the statistical distribution type assigned to the design goals, and the distribution parameters computed for the design goals. This section also displays the values that you specify for the Lower Limit and Upper Limit for the design goals. By default, the values for these limits are not specified.

2. To create a new study, click File > New and specify a name for the study. To open an existing study, click File > Open and select the name of the study from the Design Study dialog box.

4. Click Setup > MODS Response Surface to select an existing MODS. The Design Study dialog box opens listing all the saved multi-objective design studies. Select one of the listed studies. The Design Variables section displays the design variables of the selected MODS, their mean values, the statistical distribution assigned to them and their distribution parameters. The Design Goals section displays the design goals of the selected MODS and the distribution type assigned to them.

5. To update the distribution type for a specific design variable or design goal, select the type from the list under Distribution. The Normal type of distribution is selected by default for all the design variables and design goals.

6. To update the mean and statistical distribution parameters for a particular design variable, double-click any value (except for the value under Distribution) for that design variable in the Design Variables section or select any value and click Properties. The Design Variable Statistical Properties dialog box opens. The system generated graph for the distribution type, the minimum and maximum values for the design variable, the selected distribution type, and the applicable distribution parameters are displayed.

Enter the desired values for the mean and the distribution parameters applicable to the selected distribution type. You can also modify the distribution type. The display for the graph is updated as per the new values. Click OK to apply the changes and exit. Or click Cancel to exit.

• You can modify only the distribution parameters applicable to the selected distribution type in the Design Variable Statistical Properties dialog box. For example, although Mean and Standard Deviation are displayed for the Exponential and Weibull distribution types, you cannot modify these parameters. You can modify only those distribution parameters that are applicable for these types.

• Minimum and maximum values for the design variable are defined by the selected MODS response surface. Thus, you cannot modify these values.

• When the distribution type is None, the minimum and maximum values of the design variables are equal.

• You can enter only absolute values for the statistical distribution parameters in case of the Single type of design study.

7. To specify the number of samples to be computed for each operating point, click Setup > Number of samples. The Samples dialog box opens. Enter the number of samples. You can enter a value between 100 and 250000. The default value is 2000.

8. Click Options > Save samples to display the computed values for all the design variables and design goals for the specified number of samples in the .CSV format in a separate INFORMATION WINDOW. If required, click File > Save in the INFORMATION WINDOW dialog box to save the displayed information as a separate .CSV file in the Creo Parametric working directory.

• Although the Save samples option is available for both the Single and MODS types of statistical design studies, the values computed for the specified number of samples are displayed and can be saved as a .CSV file only for the type Single.

• Save samples is not selected by default.

9. Enter the values for the Lower Limit and Upper Limit for the design goals that are required for computing the DPMU and n x Sigma values. These values are computed even if you specify only one limit.

10. Click Compute to compute the minimum and maximum values and the statistical distribution parameters for the design goals. The completion percentage for the computation is displayed in the message area in the Creo Parametric window.

To abort the computation of the statistical design study, click

in the Creo Parametric message area. A Confirmation dialog box appears. Click Yes to abort the computation.

11. Double-click on any value (except for the values under Distribution, Lower Limit, or Upper Limit) for a particular design goal in the Design Goals section or select the value and click Properties. The Design Goal Statistical Properties dialog box opens. The system generated graph for the distribution type and minimum and maximum values is displayed. The computed values of the distribution parameters are also displayed.

You can update the distribution type. The display for the graph changes as per the new values entered. You can also change the values for the Lower Limit and Upper Limit for the design goals. The updated values for DPMU and n x Sigma are displayed accordingly. In the system generated graph, vertical red lines indicate the values of the user-defined limits and shaded red areas indicate the regions of defects, that is the number of experiments that fall outside the user-defined limits. Click Show samples to display the sample probability density function on the graph.

12. Click File > Save in the Statistical Design Study dialog box to save the study. If you exit without saving the study, a Confirmation dialog box appears. Click Yes to exit without saving.