Could I use only parts count to predict MTBF?

[Powen]

Could I just use parts count method to predict MTBF in Lambda Predict software?

[Kathleen]

Hi Powen,

Yes, Parts Count analysis may be used to predict MTBF in Lambda Predict. The Parts Count method requires less information such as part quantities, quality level and application environment. It is most applicable during early design or proposal phases of a project. The Parts Count method will usually result in higher failure rate or lower system reliability, a more conservative result than the Parts Stress method would produce.

Lambda Predict provides a Parts Count library with the MIL-217 Standard. Bellcore also provides a "parts count" method. It is very similar to and was modeled from the MIL-217 Standard.

I hope that this helps!

Kathleen

[Powen]

How to creat this report (use Parts Count only)?

[Kathleen]

Hi Powen,

The Lambda Predict software comes with a parts count library for the MIL-217 Standard; by default it is located in C:\Program Files\ReliaSoft\Prediction\Libraries\MIL-217\Parts Count. You may select components from this library or you may create a custom library with your own components. The Parts Count method only requires minimal information, which includes Quantity, Operating MIL-217 Environment, Generic Failure Rate and Quality factor. As you add components, Lambda Predict performs Parts Count calculation method automatically. Since Parts Count does not take into account stress parameters, it simply gives you an early approximation of the failure rates for your system without having to perform an analysis.

Additional information on using the Parts Stress analysis can be found in the MIL-HDBK-217 Standard, in Appendix A. If you do not currently have access to the MIL-HDBK-217 Standard, you may download and save it from the following link: http://www.weibull.com/knowledge/milhdbk.htm.



I hope that this helps!

Thank you,
Kathleen

[Powen]

I know parts count method, but I cannot judge the report of Lambda Predict is for parts count or parts stress.
Is the "Failure Rate" report in report selection under "File>Print>MIL-217 Reports" only a parts count report?
I load components from parts count library to system, it has all the parameter as the other libraries.
How can I do if I only want to have a parts count report?
Is there any switch function between parts stress method and parts count method?

[Kathleen]

Hi Powen,

Thank you for providing specific information regarding your question. I apologize for the misunderstanding. Lambda Predict allows you to create custom reports based on the information that you provided for each component added. As far as Lambda Predict is concerned, it does not care whether you choose to enter data as Parts Count or Parts Stress when it comes to the reports. However, if you prefer not to view certain fields in your report, you may create a custom template within the software which will eliminate the additional fields.

I hope that this answers your question.

Thank you,
Kathleen