Parts Populations

Additional Resources > Windchill Risk and Reliability Practitioner’s Guide > Reliability Prediction Methods > Generic Parts Count Method > Parts Populations

Parts Populations

Prepare a list of all parts used in the item being evaluated. Group parts by generic part type and record the Quantity ( N) of each part type (Figure 3-1 (3) and Figure 3-2 (3)).

The parts listing on the worksheet should include all parts for which generic failure rate data is given in Data Tables, as follows:

Table 3-1. Generic Failure Rate Tables
Table	Section Title and Page Number
Table A-2 through Table A-35	Discrete Electronic and Electro-mechanical Components
Table A-36 and Table A-37	Connectors
Table A-38 through Table A-47	Microelectronic Devices (Excluding Hybrids)
Table A-56	Mechanical Devices

Generic failure rate data is not given in this guide for hybrid devices. Such devices must be considered individually, and their failure rates estimated using the model given in Reliability Modelling. If all the necessary data is not available during the early design stages, reasoned approximations should be made.

Other guidelines to keep in mind follow:

• All joints and connections should be listed according to their type and should include the connections behind connectors.

• The complexity of microelectronic devices (ICs) should be stated (i.e., number of gates, bits, transistors) because generic failure rate data is related to complexity.

• Pyrotechnical and one-shot devices should not be included in the parts listing on the worksheet because their reliabilities are evaluated separately.