EPRP: Electronic Parts Reliability Prediction

RPA > Electronic Predictions contains the available standards for Electronic Parts. Specifically, Robin has the following standards:

  • MIL-HDBK-217F Notice 2 with ANSI/VITA

  • HDBK-217PlusTM

  • FIDES 2009

When the user selects one standard, the following sections appear:

  • Environmental conditions: Temperature and type of environment (if applicable)

  • Component parameters: The parameters required to be filled

  • Schematic (if any)

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By selecting a specific component, category and subcategory, the parameters change accordingly. Furthermore, Robin provides, for each parameter:

  • The units which the engineer should use when entering the parameter value, on the right side

  • (If necessary) Additional information to clarify the meaning of the parameter or usual values, on the left side

When entering all the necessary parameters, the user can compute the failure rate and the following data is obtained:

  • Failure rate in inverse Operating Hours

  • Formula applied to obtain the failure rate

  • Failure rate chart depending on the temperature (if applicable)

  • Failure rate chart depending on the environment (if applicable)

../_images/rpa_eprp2.PNG ../_images/rpa_eprp3.PNG

Note

The failure rate chart depends on the “Environment temperature” for the MIL-HDBK-217F Notice 2, and the “Operating Temperature” for the NSWC-11.

FIDES 2009

The FIDES 2009 model has specific features which make it being treated differently from other standards, as seen in the RPA > BOM. Two of its main characteristics are the prediction of the failure rate in calendar FIT and the use of special parameters (\(\pi_{PM}\) and \(\pi_{Process}\)) which are item dependent. A brief description of the FIDES special features is provided hereafter:

  • Failure Rate: The failure rate in the FIDES model is provided in calendar FIT (Failure in Time). Nevertheless, the model allows the conversion to failure rate expressed per hour operation, which is the output given by Robin to allow comparison between models. It is very important, then, to distinguish which of the life phases are operating phases and which are not in RPA > BOM. To convert the failure rate in calendar hours to failure per operating hour, the following equation is used:

\[\lambda_{operating} = \lambda_{calendar} \times \frac{Calendar \: duration}{Duration \: on-mission}\]

Note

If non of the phases is an operating phase, the failure rate is given in calendar hours

  • \(\pi_{PM}\): The Part Manufacturing factor represents the item quality, and its evaluation depends on the nature of the item considered (e.g. electronic component, board assembly, etc). It can be manually introduced or, after clicking the checkbox, automatically obtained after answering a quick survey. Ranges from 0.5 to 2.

  • \(\pi_{Process}\) : The Process factor represents the quality and technical control over reliability in the product life cycle. It can be manually introduced or, after clicking the checkbox, automatically obtained after answer a survey. The facto ranges from 1 to 8.

  • Phase-dependant Parameters: When using the FIDES model, each of the life phases of an item is considered. Several magnitudes such as the average temperature or the vibration level are general magnitudes which apply to all items included in FIDES. However, there are certain components (e.g. Integrated Circuits) which require additional parameters varying from phase to phase to compute its reliability (e.g. power dissipation). In those scenarios the parameter Phase-dependant Parameters appears and, by clicking on the checkbox, the user is able to manually introduce and save them before computing the failure rate.

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