MIL-STD-690 Failure Rate Sampling Plans And ProceduresThis standard provides procedures for failure rate FR qualification, sampling plans for establishing and maintaining FR levels at selected confidence levels, and lot conformance inspection procedures associated with FR testing for the purpose of direct reference in appropriate military electronic parts established reliability ER specifications. Figures and tables throughout this standard are based on exponential distribution. Weibull distribution will be acceptable in certain components such as capacitors. Use of Weibull distribution for any component must be approved by the qualifying activity. This standard also provides guidance to specification writers in the use of this standard see appendix A and references material for users of ER parts.

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MIL-STD-690D

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1.  SCOPE

1.1  Purpose.  This standard provides procedures for failure rate (FR) qualification, sampling plans for establishing and maintaining FR levels at selected confidence levels, and lot conformance inspection procedures associated with FR testing for the purpose of direct reference in appropriate military electronic parts established reliability (ER) specifications.  Figures and tables throughout this standard are based on exponential distribution.  Weibull distribution will be acceptable in certain components such as capacitors.  Use of Weibull distribution for any component must be approved by the qualifying activity.  This standard also provides guidance to specification writers in the use of this standard (see appendix A) and references material for users of ER parts.

1.2  Application.  This standard is applicable for reference in electronic parts ER specifications when the following conditions exist:

a.        Electronic parts are essentially the same design and are manufactured under essentially continuous production; the production process is established and controlled in accordance with MIL-STD-790.

b.        The part design and manufacturing processes produce a product whose failure rate can reasonably be assumed to be constant with time over its intended life (i.e., an exponential distribution of failures per unit time).

c.        The qualifying activity administers this standard to provide the consumer with assurance that the qualified FR level is being maintained by a given manufacturer, since these procedures in themselves are not sufficient to assure the qualified FR level.

1.3  Method of reference.  This standard can be referenced in ER specifications by specifying the following procedures:

a.    Procedure I, "Qualification at the initial FR level" (see 5.1).

b.    Procedure II, "Extension of qualification to lower FR levels" (see 5.2). c.    Procedure III, "Maintenance of FR level qualification" (see 5.3).

d.    Procedure IV, "Lot conformance FR inspection" (when specified) (see 5.4).

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