Reliability HotWire

Issue 93, November 2008

Tool Tips

* What tools are available in Xfmea/RCM++ to help monitor the progress for completing an analysis?

Xfmea and RCM++ provide three tools to help you keep track of progress in your analyses:

  • Check Analysis Utility: You can use this tool to run checks that help to make sure that the analysis is complete and consistent before you start generating reports; e.g. whether you have defined at least one cause for every failure mode, whether you have calculated the RPN for every cause, etc.
  • Statistics Window: This window provides an easy-to-read summary of the number of records in your analysis and calculated percentages to indicate whether you have completed the analysis for every function and the completion status of the recommended actions.

  • Analysis Plan Window: This window allows you to define your own custom "task list" for the analysis project and track the completion of these tasks. (For an in-depth look at the Analysis Plan window, see the Tool Tips in Reliability Hotwire Issue 61.)

* How can I use DOE++'s Modify Design window?

Last month's Tool Tips discussed the wide variety of changes that can be made to an existing design in DOE++. This month, we offer more specific information on the Modify Design window, available beginning in version 1.0.2.

To access the Modify Design window, choose Modify Design from the Data menu or click the icon in the Control Panel.

The Modify Design window is shown next.

This window allows you to do the following:

  • Add replicates: Adding replicates allows you to increase the number of tests to take under each factor setting combination (e.g. the number of samples you want to test at each setting combination). The ability to add replicates is available for all design types.
  • Add center points: Center points are used primarily to help determine if there is curvature in the relationship between the factors and the response. In addition, using several center points allows you to estimate "noise," or "error." The ability to add center points is available for standard factorial and response surface method designs with at least one quantitative factor. For general full factorial and Taguchi OA designs, all factors must be quantitative.
  • Fold the design: Folding replicates the design, but toggles the coded values of the selected factor(s). For example, if you fold over Factor A, the design will be replicated and in each new row the value of Factor A will be opposite of what it was in the original row that was copied (i.e. the -1 values will be replaced with the 1 values and vice versa). The ability to fold the design is available for designs with two levels (i.e. standard and reliability two level full factorial, two level fractional factorial and Plackett-Burman designs).
  • Add an axial block: Adding an axial block converts the current design into a central composite design (if it is not already) by adding axial runs. The ability to add an axial block is available for all standard factorial and response surface method designs such that all factors are quantitative.

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